Clinical Evaluation

The most frequent mode of presentation of a bone tumor is a mass lesion or symptoms that result from pressure on contiguous neurovascular structures or viscera or the adjacent dentition. However, many small lesions are discovered incidentally on imaging studies performed for other reasons. Symptoms also may arise for tumors of the maxilla as a result of compression of the orbit, or displacement of the orbital contents, or obstruction of the nasal passages. Thorough radiographic evaluation and tissue diagnosis, is mandatory for surgical treatment planning.

Imaging

Accurate assessment of the anatomic extent of a lesion of the craniofacial skeleton requires its evaluation in all three dimensions. Plain films of the mandible and skull are used rarely. A panoramic radiograph (orthopantomogram) of the mandible provides an overview of the dentition and architecture of the mandible ( Fig. 16.9 ). However, for more detailed assessment of the mandible, a computed tomography (CT) or magnetic resonance imaging (MRI) scan is required. A CT scan is excellent for bony architecture, whereas assessment of the soft tissues and bone marrow and inferior alveolar nerve in the mandible is better with MRI. Whenever a CT scan is requested for evaluation of a neoplastic process with invasion of bone and soft tissue, the scan should be obtained with contrast enhancement, and both soft tissue and bone windows should be carefully scrutinized.

A panoramic radiograph of the mandible showing a large cystic lesion.

The patient whose CT scans of the upper alveolus are shown in Figs. 16.10 and 16.11 has a myxoma of the alveolus extending into the maxilla. The soft-tissue window shown in Fig. 16.10 gives excellent soft-tissue detail, but the fine architectural detail of the bone is obscured. On the bone window shown in Fig. 16.11 , the soft-tissue detail is obscured and the fine architecture of the bone and the lesion are clearly seen. Thus for adequate evaluation of bone invasion by a neoplastic process, both soft tissue and bone windows of the CT scan are required. An axial view of the CT scan of a patient with a massive expansile cystic lesion involving the body of the mandible on the left-hand side with significant expansion of the lateral cortex of the mandible is shown in Fig. 16.12 . The lesion has a uniform ground glass appearance without any bone destruction or new bone formation. The reconstructed sagittal view of the CT scan shown in Fig. 16.13 demonstrates a large, unilocular cystic space extending from the region of the retromolar trigone posteriorly up to the lateral incisor anteriorly. The cystic space has clear content and a smooth margin that is well defined. The roots of the teeth are within the cystic space. Three-dimensional reconstruction of the CT scan images clearly demonstrate the large expansile cystic lesion with bone loss in the body of the mandible ( Fig. 16.14 ).

A soft-tissue window of an axial computed tomography scan through the upper alveolus demonstrating a hypodense, expansile, bone-destructive lesion.

A bone window of the axial computed tomography scan of the patient shown in Fig. 16.10 demonstrating the expansile bone-destructive lesion of the upper alveolus.

An axial view of the computed tomography scan of the patient shown in Fig. 16.9 reveals an expansile cystic lesion of the body of the mandible.

The sagittal view of the computed tomography scan of the patient shown in Fig. 16.9 reveals the anteroposterior extent of the lesion and its relation to the dental roots.

The lateral and inferior views of the three-dimensional reconstruction of the computed tomography scan of the patient shown in Figs. 16.9 through 16.11 showing the expansile lesion ( arrow ).

Three-dimensional reconstruction of CT images are very helpful in surgical treatment planning for resection and reconstruction. Three-dimensional computer-aided design/computer-aided manufacturing (CAD-CAM) models can also be fabricated with computer software, which provides three-dimensional printed guides for bone resection and reconstruction, thus facilitating the ability of the reconstructive surgeon to accurately fabricate a graft or flap to achieve exact contour and symmetry (see Chapters 17 and 18 ). A three-dimensional reconstruction of the mandible of a young patient with fibrous dysplasia of the mandible is shown in Fig. 16.15 . Note the shape and dimensions of the lesion of the mandible in relation to the remaining facial skeleton. In a posterior view of the reconstructed CT scan, the thickness of the mandible involved by fibrous dysplasia is vividly demonstrated ( Fig. 16.16 ). An axial view of the CT scan of the same patient shows thickening of the cancellous bone with thinning out of the mandibular cortex. The normal architecture of the cancellous bone is lost and is replaced by a ground glass appearance due to fibrous dysplasia ( Fig. 16.17 ).

A three-dimensional computed tomography reconstruction showing an expansile lesion of the mandible.

The posterior view of the three-dimensional computed tomography reconstruction demonstrates the full-thickness involvement of the mandible.

An axial view of the computed tomography scan (bone window) shows the featureless “ground glass” appearance of the pathologic bone.

Paget’s disease of the craniofacial skeleton has a characteristic appearance on a CT scan with thickened bones with an irregular ground glass patchy appearance. Malignant transformation in a bone involved with Paget’s disease clearly shows a punched-out demarcation with the sarcoma in the involved bone, while the remaining bone shows the Paget’s disease in the background ( Fig. 16.18 ). The radiographic appearances of several other bone lesions are shown later in this chapter as the surgical procedures are described. Many tumors and tumorlike conditions have characteristic radiographic appearances that almost pinpoint the diagnosis. However, tissue diagnosis is mandatory before implementation of therapy.

Axial view of CT scan of the skull in bone window shows the entire calvarium involved by Paget’s disease, and a bone-destructive sarcoma in the frontoparietal region.

Pathology

It is vitally important that accurate tissue diagnosis be established before definitive surgical treatment in patients who present with lesions suspicious of being a neoplastic process involving the facial skeleton. Several bone lesions are benign or of a low-grade malignant histology, and their treatment is significantly different than for high-grade malignant tumors. Because needle biopsy is often not satisfactory, an open biopsy with a generous volume of representative tissue should be submitted for pathologic analysis. Frozen section diagnosis is generally not possible and should not be requested when a bone tumor is suspected. Extraction of a tooth near lesions of the upper or lower jaw should be avoided, and a biopsy from an adjacent area should be obtained to prevent implantation of malignant tumor into the marrow cavity of the affected bone, which would increase the risk of tumor dissemination.

The World Health Organization (WHO) histologic classification of bone tumors is shown in Table 16.1 .

Soft-tissue chondromas (synonyms: fibrochondroma, myxochondroma, osteochondroma, chondroma of soft parts, extraskeletal chondroma) are benign cartilaginous tumors that, on rare occasion, may arise in the larynx and craniofacial bones, including the palate. These benign tumors may also occur extraskeletally, whereby they are referred to as soft-tissue chondromas. They present as well-circumscribed, nodular masses and may be particularly difficult to differentiate histologically from low-grade chondrosarcoma, particularly on small biopsy samples. These tumors are composed of mature hyaline cartilage with a lobular pattern of growth and cells that are immunoreactive for S-100 protein. Although they do not generally dedifferentiate to chondrosarcoma, incomplete excision of these tumors may lead to local recurrence.

Chondrosarcoma is the malignant counterpart to chondroma and is defined as a malignant tumor of hyaline cartilage. Like chondromas, these are rare neoplasms of the head and neck, but when they occur, they most commonly arise in the maxilla, mandible, larynx, and nasopharynx, in decreasing order of frequency. These tumors are composed of nodules of myxoid and hyaline cartilage, with neoplastic chondrocytes displaying varying degrees of atypia ( Fig. 16.19 ). The severity of atypia defines tumor grade in a three-tiered grading system. Increasing grade is characterized by increasing pleomorphism, mitotic activity, abnormal mitotic figures, and binucleation. Differentiating grade III chondrosarcoma from chondroblastic osteosarcoma is of prognostic significance, because the former has a much better outcome. Ancillary studies are not generally necessary for diagnosis; rather, the absence of osteoid allows distinction of high-grade chondrosarcoma from the chondroblastic osteosarcoma. Metastases are infrequent, with an 83% 5-year survival for grade I chondrosarcoma and 53% combined 5-year survival for grades II and III.

A , The nodular growth of this laryngeal chondrosarcoma is readily appreciated on low-power view (25×; H&E). B , At slightly higher magnification (50×; H&E), multiple abnormal chondrocytes crowded within lacunar spaces are seen.

Osteoid osteoma (synonym: osteoma) is a slowly growing, hamartomatous or developmental lesion composed of cortical bone. It has no malignant potential and may indeed regress in size over time. There is some association between multiple osteomas and Gardner’s syndrome. Osteomas most commonly arise from the metaphyses of long bones. In the head and neck, they generally involve the frontal bone, calvarium, mandible, or sinonasal bones. They present as small lesions, 1 to 2 cm in size, with a central nidus of proliferating cells that appear less dense than the adjacent bone on radiographic imaging. Histologically, these are bland proliferations of dense bony spicules, morphologically similar to the surrounding bone, rimmed by osteoblasts, and surrounded by fibrous tissue with an abundance of vessels ( Fig. 16.20 ). Sclerotic bone may surround the lesion.

Osteoid osteoma (10×; H&E) shows abundant dense eosinophilic cortical bone.

(Photograph courtesy Dr. Mark Edgar, Emory University.)

Osteosarcoma (synonyms: osteogenic sarcoma, osteoblastic sarcoma, chondroblastic osteosarcoma, medullary osteosarcoma) is a malignant tumor defined by neoplastic bone formation. The WHO classification includes several morphologic variants (e.g., chondroblastic, fibroblastic, telangiectatic, small cell), as well as variants based on the site from which the tumor arises (e.g., periosteal versus endosteal). Grossly, these are hard, destructive osseous neoplasms, which, in the head and neck, are most commonly intraosseous in location. The mandible is the most common primary site, followed by the maxilla and the skull. Histologically, these are matrix-producing tumors whose neoplastic osteoblasts produce bone. These malignant osteoblasts are usually highly pleomorphic and may be plasmacytoid, spindled, epithelioid, or round or have a mixture of these features ( Fig. 16.21 ). Approximately half of all lesions are high grade. Ancillary studies are generally not used in the pathologic diagnosis of osteosarcoma. If a patient has been treated with preoperative chemotherapy, histologic grading of therapeutic response should be reported because it is an important predictor of outcome.

High-grade osteosarcoma of the mandible showing neoplastic bone formation, surrounding normal cortical bone ( A ) and numerous mitoses and marked nuclear atypia ( B ).

(Photograph courtesy Dr. Mark Edgar, Emory University.)

Plasmacytoma (synonyms: plasma cell myeloma, solitary plasmacytoma of bone, myeloma) is a malignant primary neoplasm of bone composed of plasma cells. When present as a single, localized mass, defined by a proliferation of clonal, terminally differentiated B cells (plasma cells), the lesion is a called a plasmacytoma. When there are multifocal, lytic bone lesions, this malignant proliferation of plasma cells is termed multiple myeloma. Histologically, these tumors are made up of a uniform population of lymphoid cells with eccentric nuclei, which are round to oval, demonstrating a pattern of chromatin distribution referred to as “clock face chromatin.” When there is marked nuclear pleomorphism, with increased and abnormal mitoses, the tumors may be referred to as “undifferentiated” or “anaplastic” or “poorly differentiated.” The malignant plasma cells demonstrate immunoreactivity to antibodies against CD138, CD79a, and vimentin, whereas LCA (leukocyte common antigen) and CD20, which are both normally expressed by mature B cells, are negative. These tumors can also occur in soft tissue, as shown in this patient with a laryngeal plasmacytoma ( Fig. 16.22 ). Plasmacytomas often also demonstrate light chain restriction, either kappa or lambda. Prognosis depends on stage, with systemic disease defined by high mortality rates at 3 years and an approximately 10% 10-year survival.

Kappa light chain restricted CD138 plasma cell neoplasm of the larynx. A , This submucosal proliferation of neoplastic plasma cells formed a small nodule beneath the respiratory mucosa of the ventricle in the larynx (25×; H&E). B , Higher magnification (400×; H&E) demonstrates the eccentrically located nuclei of these CD138-positive plasma cells in the patient with widely disseminated multiple myeloma.

Giant cell granuloma (synonyms: giant cell reparative granuloma, solid aneurysmal bone cyst, brown tumor, central giant cell lesion) is an osteolytic, poorly defined intraosseous lesion of the jaw defined by an abundance of osteoclast-type giant cells that can be seen irregularly distributed throughout a background of proliferating reactive blood vessels and fibroblasts and often with associated hemorrhage. In the past, these lesions were deemed purely reactive, but there appears to be some recent molecular evidence that they may be related to aneurysmal bone cysts, with associated identical translocations. The exact same histologic appearance may also be seen in hyperparathyroidism, and the lesion is then called a brown tumor, although the molecular aberrations are distinct from giant cell granuloma. Microscopically, it is unencapsulated and has nests of multinucleated osteoclast-type giant cells in a fibrovascular stroma ( Fig. 16.23 ). Ancillary studies are not necessary in the diagnosis, although it is important to evaluate serum calcium levels and parathyroid hormone to exclude hyperparathyroidism. It is also important to differentiate this lesion from giant cell tumor of bone, as behavior, prognosis, and treatment can be different.

Giant cell reparative granuloma of the mandible, which radiographically presented as a lytic lesion in a patient with hyperparathyroidism. A , Histologic appearance at 25×; H&E. B , Benign, reactive multinucleated giant cells are seen at 400×; H&E.

Giant cell tumor of bone is a benign, but potentially aggressive neoplasm, which on rare instances may be seen in the craniofacial bones. On radiographic imaging, it has poorly defined borders and presents as a destructive, lytic lesion. Histologically, giant cell tumors share many morphologic features with giant cell granuloma; however, there is also a proportionate abundance of mononuclear cells and the giant cells are often very large, with 50 to 100 nuclei. Although mitotic activity is common, abnormal mitoses are not seen. These tumors can recur, can be very locally destructive, and do metastasize infrequently.

Ewing sarcoma and primitive neuroectodermal tumor (synonyms: primitive neuroepithelioma; ES/PNET, EWS) is a malignant “small round blue cell tumor” of bone and soft tissue, composed of undifferentiated cells of neuroectodermal origin. Almost 10% of Ewing sarcomas arise in the head and neck, most commonly in the mandible, followed by the maxilla. It may have a bimodal age distribution, with a higher frequency peak in children, and then a second, much smaller peak in older adults. On rare occasions, Ewing sarcoma may be metastatic to the jaw. Histologically, these tumors are high grade by definition and are composed of primitive, small, round uniform cells, which may form rosettes and fibrillary processes ( Fig. 16.24 ). Tumors in the ES/PNET group are characterized by a EWS-FLI fusion, t(11;22) (q24;q12), with several variants of this translocation producing other fusion products. The particular translocation and the corresponding fusion transcript directly affect the outcome, and long-term survival may be as high as 85%.

Sinonasal Ewing sarcoma demonstrates marked nuclear pleomorphism and an epithelioid appearance with 200× ( A ) and 400× ( B ); H&E.

Undifferentiated pleomorphic sarcoma (UPS) (synonyms: malignant fibrous histiocytoma, MFH, xanthosarcoma, malignant fibrous xanthoma, fibroxanthosarcoma, malignant histiocytoma) is a high-grade malignant neoplasm of soft tissue or bone and is essentially a diagnosis of exclusion. It is a malignant storiform neoplasm arising from histiocytes ( Fig. 16.25 ) or from cells capable of histiocytic differentiation. Because this tumor’s immunophenotype is nonspecific and the diagnosis is made by excluding other neoplasms, immunohistochemistry is used to rule out other spindle cell neoplasms of definable lineage.

Undifferentiated pleomorphic sarcoma (UPS), malignant fibrous histiocytoma (MFH) of the larynx seen as a high-grade, pleomorphic mitotically active malignant spindle cell neoplasm (25× [ A ] and 100× [ B ]; H&E). Immunohistochemical studies were negative for melanoma markers (HMB45, S-100 protein), cytokeratins (CAM 5.2, 34Be12, and AE1:AE3), and muscle markers (HHF-35, SMA, and Desmin).

Extrapleural solitary fibrous tumor (SFT; synonyms solitary fibrous tumor; hemangiopericytoma (obsolete); giant cell angiofibroma) is categorized by the WHO (2017) as a mesenchymal neoplasm of fibroblastic type that forms staghorn-patterned or “hemangiopericytoma-like vascular patterns, which are most commonly benign, although there is a malignant SFT as well. The tumor cells are positive for CD34, bcl2, and CD99; 20% to 30% show variable immunoreactivity for EMA and SMA. More than 70% of these tumors are benign, and histology is not necessarily predictive of behavior, although those with marked mitotic activity, necrosis, and nuclear pleomorphism are more likely to metastasize.

Odontogenic Tumors

The WHO (2017) classification of odontogenic tumors divides these pathologic entities into malignant odontogenic tumors (carcinomas and sarcomas), benign odontogenic tumors (epithelial, mesenchymal, and mixed origin), and odontogenic cysts (developmental or inflammatory) ( Table 16.2 ).

Ameloblastoma is a benign tumor of ameloblasts, which essentially recapitulates the development of the early tooth-forming apparatus without the formation of enamel or its precursors. As a group, 20% are seen in the maxilla, and 80% occur in the mandible, distributed as follows: 70% molar and ascending ramus, 20% premolar region, and 10% incisor region. They are divided into unicystic ameloblastoma, multicystic or solid ameloblastoma, peripheral ameloblastoma, and malignant ameloblastoma. The pathologic classification further defines ameloblastoma into four varieties: (1) conventional, (2) unicystic, (3) extraosseous/peripheral, and (4) malignant (metastasizing) ameloblastoma. Histologically, these tumors contain nests and islands of odontogenic epithelium with central stellate reticulum-like cells surrounded by peripheral tumor cells that most commonly have subnuclear vacuoles ( Fig. 16.26 ). Unicystic ameloblastoma is unilocular and cystic with an epithelial lining consisting of ameloblastoma cells. This entity is seen to arise in young adults, almost exclusively in the mandible, with more than two-thirds of the lesions in the molar-ramus region. These are thought to be less aggressive than multicystic ameloblastoma. Unfavorable prognostic indicators for ameloblastoma include maxillary location in an older adult and extension of tumor from bone into adjacent soft tissue. Marked mitotic activity, nuclear pleomorphism, tumor necrosis, and evidence of metastasis would indicate a diagnosis of malignant ameloblastoma.

Ameloblastoma of the maxilla (100×; H&E) showing subnuclear vacuoles, giving the periphery of the tumor a “picket fence–like” appearance.

OKCs are cystic lesions that may be associated with the roots of teeth or impacted teeth and represent 5% to 15% of all odontogenic cysts. In up to almost 80% of cases of Gorlin-Goltz syndrome (also known as nevoid basal cell carcinoma syndrome ), the diagnosis of OKC may be the first diagnostic indicator of the underlying genetic disorder. Histologically, these lesions typically display a stratified squamous epithelium of six to eight layers with a corrugated parakeratinized surface layer ( Fig. 16.27 ). These lesions may be locally aggressive, with recurrence rates reported around 30%. Local recurrence has been correlated with the presence of islands of odontogenic epithelium in the cyst wall. There are rare case reports of squamous cell carcinoma arising in these lesions, but that is the exception and not the norm.

A , Odontogenic keratocyst showing squamous epithelial lining of the cyst wall. There are typically no odontogenic epithelial nests within the cyst wall (25×; H&E). B , At higher magnification (100×; H&E), the absence of cytologic atypia is apparent.

Principles and Goals of Treatment

Surgical excision is the preferred modality of therapy for nearly all bone tumors arising in the head and neck region. Most symptomatic benign lesions can be treated adequately by a relatively conservative excision but preferably in a monobloc fashion depending on the size and location of the tumor. In a similar fashion, low-grade malignant tumors such as a low-grade chondrosarcoma and low-grade fibroosseous lesions also are managed by a relatively conservative surgical resection. On the other hand, high-grade malignant tumors require an aggressive surgical approach for satisfactory resection with adequate bone and soft-tissue margins. Histologically aggressive tumors require multimodality treatment to improve local control and reduce the risk of local recurrence or distant metastases. Solitary, symptomatic metastatic tumors to the craniofacial skeleton from primary carcinomas of the kidney, thyroid, lung, and breast occasionally may require surgical resection. Some lesions such as fibrous dysplasia are polyostotic. Involvement of multiple bones clearly would influence the decision for surgical treatment. Appropriate workup therefore should be undertaken to rule out multiple bone involvement.

Lesions of odontogenic origin usually are managed in a conservative fashion. An ameloblastoma is a locally invasive process that usually is treated by “complete excision” to avoid local recurrence. Small, localized ameloblastomas may be suitable for a relatively conservative excision, but larger tumors require complete resection that may include a segmental mandibulectomy or a maxillectomy. Similarly, small cystic ameloblastomas can be treated by curettage and marsupialization, but larger lesions require more aggressive resection. Curettage for larger lesions is unlikely to be successful and almost uniformly results in recurrent disease.

Neoadjuvant multidrug chemotherapy followed by surgical resection has become the standard of care for treatment of osteosarcoma of the extremities in the pediatric age group. The efficacy of this approach in head and neck osteosarcomas in the adult is however unproven. Thus primary surgical resection followed by adjuvant radiation therapy currently is recommended as the most effective treatment for head and neck osteosarcomas. Chondrosarcomas and other rare variants of bone sarcomas generally are treated with appropriate surgical resection. Proton beam radiation therapy for chondrosarcomas in an adjuvant setting has shown improved local control compared with conventional radiation therapy with photons. Treatment options for Ewing sarcoma have improved with the use of multidrug chemotherapy and radiation therapy, reserving salvage surgery for residual disease. A plasma cell tumor generally is managed with radiation therapy, keeping surgery in reserve for salvage. Treatment for multiple myeloma and lymphoma is systemic chemotherapy with or without radiation therapy.

Preoperative Preparation

Most patients requiring surgery for tumors of the craniofacial bones do not need any specific preoperative preparation other than imaging studies and accurate tissue diagnosis. If a massive resection is contemplated where significant blood loss is anticipated, then sufficient quantities of blood should be available to replace operative blood loss. Highly vascular lesions may be considered for preoperative embolization before surgical resection.

If the upper alveolus or maxilla is to be resected, then preoperative consultation from the maxillofacial prosthetic department should be obtained for preoperative dental impressions and fabrication of a dental obturator. If surgical resection entails orbital exenteration or resection of a major portion of facial bones, then preoperative photographs and facial moulage should be obtained for fabrication of facial/orbital prostheses. On the other hand, if bone reconstruction is planned after resection of the tumor, then CAD-CAM planning and modeling is strongly recommended to reduce operating time in designing an appropriate free bone flap to achieve accurate reconstruction. (See Chapter 17 for details.) Similarly, if a mandibulectomy is planned, then a microvascular free flap reconstruction from an appropriate donor site, generally from the fibula, should be planned with assistance of CAD-CAM modeling.

Lesions involving the calvarium or the skull base require neurosurgical consultation for a combined craniofacial approach for adequate surgical resection. In patients requiring craniofacial resections, antibiotics and steroids should be administered preoperatively to reduce the risk of postoperative sepsis and brain edema. Surgical resection of vertebral bodies requires adequate stabilization of the spine, which may require either neurosurgical or orthopedic consultation for posterior stabilization of the spine or to ascertain the availability of a halo splint for postoperative immobilization.

The operative procedures in this chapter are not discussed by tissue of origin, as was done in the chapter on soft-tissue tumors. Instead, the management of osseous tumors is described by the bones of origin, starting from the calvarium, skull base, maxilla, mandible, and cervical spine.

Tumors of the Calvarium

Primary bone tumors of the calvarium are exceedingly rare. The benign lesions most frequently seen are osteomas and hemangiomas. The malignant tumors most frequently seen are osteogenic sarcoma, chondrosarcomas, other sarcomas, and metastatic lesions. The indications for surgery are related to histologic diagnosis and symptoms. Some benign lesions are asymptomatic and may simply be kept under observation.

Hemangioma of the Frontal Bone

Hemangiomas of the craniofacial skeleton are usually asymptomatic and present simply as a bony mass. On occasion the lesions get large and produce a skeletal deformity that requires surgical intervention. In addition, because of the progressive growth of the lesion, some patients have symptoms that warrant surgical intervention. A hemangioma in a stress-bearing bone may require surgical intervention to avoid a pathologic fracture. The most common site of hemangiomas in the craniofacial skeleton is the calvarium. The CT scan of a patient with a hemangioma of the parietal region is shown in an axial view ( Fig. 16.28 ). Note the well-demarcated bony defect and the honeycomb appearance of the involved outer cortex of the calvarium. The bone window of the CT scan demonstrates a punched-out area of the frontoparietal region involved by the hemangioma ( Fig. 16.29 ). The lesion had shown growth over the course of a year and was symptomatic with local pain at the site.

An axial view of the computed tomography scan (soft-tissue window) demonstrating the well-demarcated defect in the outer table with a “honeycomb” appearance.

The bone window of the computed tomography scan of the same patient as in Table 16.1 shows the punched-out defect in the frontal bone.

Surgical excision of the lesion requires a full-thickness craniectomy and an appropriate cranioplasty. The entire operative procedure is extradural. The patient is placed under general endotracheal anesthesia, and the scalp is shaved and prepared in the usual fashion. A U-shaped incision is made over the scalp around the palpable tumor, with the pedicle of the flap based anteriorly. The scalp flap is elevated deep to the pericranium, exposing the outer cortex of the frontoparietal region ( Fig. 16.30 ). Note the purplish color of the hemangioma involving the bone. Two burr holes are made, one anterior and the other posterior to the lesion. With use of appropriate dural elevators, the underlying dura is separated from the inner cortex of the bone to free the area of bone involvement. A Midas Rex side-cutting power saw is used to complete the craniectomy by connecting the burr holes around the visible and palpable tumor. The surgical specimen is removed in a monobloc fashion ( Fig. 16.31 ). Accurate hemostasis is secured by using bipolar cautery for control of bleeding from the dura and bone wax over the cut edges of the calvarium.

The scalp flap is elevated to expose the hemangioma.

The surgical specimen.

A cranioplasty of the craniectomy defect can be performed with a variety of different techniques. The simplest technique is to use a braided wire and bone cement. The wire is crisscrossed between the edges of the surgical defect, and bone cement is used to fill the surgical defect. The wire acts as a matrix over which the bone cement is spread to provide a shell to repair the craniectomy defect ( Figs. 16.32 and 16.33 ). Alternatively, a titanium mesh can be used to provide a matrix of support for the bone cement, or special cranioplasty plates may be used without the bone cement to repair small surgical defects ( Fig. 16.34 ). On the other hand, a computer-assisted cranioplasty prosthesis can be fabricated from Porex. The scalp incision is then closed over the cranioplasty in the usual manner.

Braided wire is crisscrossed between the edges of the surgical defect.

The wire acts as a matrix over which the bone cement is placed to provide a shell to repair the craniectomy defect.

A titanium mesh or cranioplasty plate can be used to reconstruct the craniectomy defect.

Sarcoma of the Frontal Bone

Malignant tumors of the calvarium that are adherent to the overlying scalp and underlying dura require through-and-through monobloc resection. However, when these tumors involve the anterior cranial fossa, a craniofacial resection becomes necessary. If the tumor involves one orbit, then orbital exenteration in conjunction with a formal craniectomy and en bloc excision is indicated.

The patient described here has Paget disease involving the skull. He presented to a local surgeon with an enlarging mass on his forehead of approximately 6 months’ duration. A generous open biopsy was performed with a transverse incision in the skin of the forehead, which confirmed the diagnosis of osteogenic sarcoma ( Fig. 16.35 ).

A patient with a bony lesion on the forehead. The scar of an open biopsy is visible.

A CT scan of the head in an axial plane with a soft-tissue window shows significant intracranial extension of disease with displacement and/or involvement of the dura and the frontal lobe on the left-hand side ( Fig. 16.36 ). A representative axial view of the CT scan with a bone window shows the entire skull involved with Paget’s disease ( Fig. 16.37 ). The tumor involves the frontal bone on the left-hand side with extension of disease to involve the medial part of the frontal bone on the right-hand side. Significant soft-tissue extension is present in an extracranial fashion. A coronal view of the CT scan shows direct extension of the tumor in the orbit through its roof, displacing the globe inferiorly and laterally ( Fig. 16.38 ). However, the tumor does not extend to involve the contents of the nasal cavity.

An axial computed tomography scan with a soft tissue window showing a massive tumor with intracranial and extracranial extension.

An axial CT scan of the head with a bone window showing the bone-destructive tumor and involvement of the cranium with Paget’s disease.

A coronal view of a computed tomography scan showing extension of the tumor into the orbit.

The operative procedure in this clinical setting requires involvement of two surgical teams. A neurosurgical team will begin with the craniotomy, and the head and neck team will accomplish the facial aspect of the procedure and reconstruction of the surgical defect with appropriate scalp flaps. A third surgical team for microvascular free tissue transfer may be required if free flap reconstruction of the surgical defect is planned. The technical details of craniofacial resection are discussed in Chapter 6 . An artist’s rendering of the extent of the tumor resection is shown in Fig. 16.39 .

An artist’s rendering of the proposed extent of surgical resection.

The surgical specimen shows the orbit, the frontal bone with the tumor, and the overlying skin excised in a monobloc fashion ( Fig. 16.40 ). The posterior view of the specimen shows the excised portion of the dura and the frontal lobe ( Fig. 16.41 ). The surgical defect of the craniectomy is continuous with the lower half of the orbital socket and the contents of the frontal fossa with exposed brain in that region. A close-up view of the surgical defect shows exposed brain of the left frontal lobe with a large dural defect due to its resection with the specimen ( Fig. 16.42 ). Laterally, the stump of the temporalis muscle is visible in the temporal region.

The anterior view of the surgical specimen.

The posterior view of the specimen showing the intracranial tumor and the resected portion of the dura.

A close-up view of the surgical defect showing the exposed brain and the dural defect.

A large segment of the periosteum from the posterior aspect of the skull is now excised and used as a free graft to repair the defect in the dura. The periosteum is sutured to the dura with 4-0 Nurolon sutures. A watertight closure is obtained to prevent any cerebrospinal fluid (CSF) leakage ( Fig. 16.43 ).

A watertight closure is obtained.

A massive defect such as this is best reconstructed with a computer-assisted Porex prosthesis for bone reconstruction and soft tissue and skin free flap for coverage. A postoperative CT scan demonstrates total excision of the tumor of the frontal region with satisfactory margins ( Fig. 16.44 ).

A postoperative computed tomography scan.

Metastatic Tumor to the Calvarium

Tumors of the calvarium that involve the overlying scalp require a through-and-through resection, often including the underlying dura. Primary tumors of the scalp invading the skull and primary tumors or symptomatic metastatic tumors of the calvarium warrant this type of surgical resection.

The plain radiographs of the skull demonstrate a bone-destructive lesion involving the cranial vault in the parietooccipital region on the right-hand side ( Figs. 16.45 and 16.46 ). The soft-tissue windows of the CT scan of the patient shown here clearly demonstrate a bone-destructive lesion, which involves the overlying scalp with extension through the cranium to involve the underlying dura ( Fig. 16.47 ). The extent of bone destruction is shown by a punched-out area of the calvarium on the bone window ( Fig. 16.48 ). A needle aspiration biopsy of this lesion confirmed the diagnosis of metastatic renal cell carcinoma that was a solitary metastasis.

The anteroposterior view of the plain radiograph of the skull.

The lateral view of the plain radiograph of the skull showing the osteolytic lesion ( arrow ).

A computed tomography scan of the skull with a soft-tissue window shows the extracranial and intracranial component of the tumor.

A computed tomography scan of the skull with a bone window shows a punched-out area of bone destruction.

The patient is placed under general anesthesia in the supine position on the operating table with the left parietal region of the head resting on a standard U-shaped head rest ( Fig. 16.49 ). The shaved scalp clearly shows the gross dimensions of the lesion. An indwelling spinal catheter is placed to monitor CSF pressure and to facilitate withdrawal of CSF to slacken the brain if necessary.

The patient in position for surgery.

The incisions are outlined on the scalp ( Fig. 16.50 ). The extent of the scalp that will need to be sacrificed to resect the tumor is shown. A parietal scalp flap is outlined; this scalp flap is based on the left-hand side, with the entire scalp elevated from the pinna of the ear on the right-hand side all the way up to the pinna of the ear on the left-hand side ( Fig. 16.51 ). The blood supply to this flap is derived from the superficial temporal, posterior auricular, and occipital arteries of the left-hand side. The scalp flap is elevated all the way up to the pinna of the ear and the mastoid process on the left-hand side. The flap is elevated in a subgaleal plane, remaining superficial to the pericranium, which will be used later to repair the defect.

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