Cartilaginous Tumors
A range of cartilaginous tumors can occur in this region, exhibiting a spectrum of histological aggressiveness. However, all should be regarded as having malignant potential. Even those that never metastasize are capable of insidious local infiltration which, in the skull base, can ultimately cause the demise of the patient. Thus, radical treatment from the outset is recommended.
Chondroma
(ICD-O code 9220/0)
True benign cartilaginous tumors are extremely rare and distinction between this and a well-differentiated chondrosarcoma can be difficult.1,2 Thus early cases such as that described by Muller in 1836 must be regarded with some circumspection.3
Sometimes referred to as ecchondromas, they are surprisingly rare in the cartilaginous septum, more often affecting the ethmoid and maxilla, suggesting that they may arise from focal hypertrophy of heterotopic nests of cartilage within the mucosa.
A well-circumscribed lesion, without mitoses, which can be completely excised may qualify as a true chondroma but is rarely encountered.
References
1. Fu YS, Perzin KH. Non-epithelial tumors of the nasal cavity, paranasal sinuses, and nasopharynx: a clinicopathologic study. 3. Cartilaginous tumors (chondroma, chondrosarcoma). Cancer 1974;34(2):453–463 2. Michaels L, Hellquist H. Ear, Nose and Throat Histopathology. 2nd ed. New York: Springer; 2000:236–237 3. Muller M. Die Chondrom. Arch Klin Exp Ohren Nasen Kehlkopfheilkde (Berlin) 1870;12:323Chondroblastoma
(ICD-O code 9230/0)
Chondroblastoma typically affects the epiphyseal end of long bones such as the distal femur and occurs in young people less than 20 years old. The tumor is composed of chondroblasts in a chondroid matrix with foci of calcification. This may give it a similar appearance on imaging to a well-differentiated chondrosarcoma. The presence of giant cells may also make histological differentiation from a giant cell tumor difficult.
There are a very small number of case reports of chondroblastoma affecting the upper jaw,1,2 though the lesion is somewhat more common in the temporal bone.
Although curettage has been used, ideally a complete resection should be undertaken by whatever surgical approach is possible. Radiotherapy is not recommended because of the potential risk of provoking malignant change.
References
1. Al-Dewachi HS, Al-Naib N, Sangal BC. Benign chondroblastoma of the maxilla: a case report and review of chondroblastomas in cranial bones. Br J Oral Surg 1980;18(2):150–156 2. Madhup R, Srivastava M, Srivastava A, Bhatt M, Kirti S. Chondroblastoma of maxilla. Oral Oncol Extra 2005; 41:159–161Chondromyxoid Fibroma
(ICD-O code 9241/0)
Chondromyxoid fibroma is a rare benign tumor of cartilaginous origin.
It is most often seen in adolescents and young adults, in whom it affects the long bones such as the tibia.1,2 It is extremely rare in the sinonasal region, where the maxilla is the most frequently affected. From there, adjacent structures such as the nasal bones, ethmoid, sphenoid, clivus, and orbit may be involved.3–5
Macroscopically it forms a discrete mass that causes nasal obstruction, facial swelling, and/or displacement of the orbital contents.
Imaging shows a circumscribed expansile lesion with a sharply delineated lobulated margin (Fig. 11.1a and Fig. 11.2).6 Microscopically it is also lobulated, composed of spindle or stellate cells in a myxochondroid stroma. It can be aggressive and so must be distinguished from chordoma and chondrosarcoma.7
Complete surgical excision is curative by whatever approach is appropriate, otherwise “recurrence” can be anticipated.8 One of our cases occurred in an Italian boy of 7 years of age who underwent a craniofacial resection in 1990 without recurrence over 10.5 years follow-up, although it is almost certain that if he presented today an endoscopic excision would be undertaken (Fig. 11.1b).9 A second case is that of a 30-year-old woman who had had surgery performed abroad and was left with residual disease in the nasal cavity. After histological confirmation, she has recently undergone an endoscopic resection (Fig. 11.2).
References
1. Rahimi A, Beabout JW, Ivins JC, Dahlin DC. Chondromyxoid fibroma: a clinicopathologic study of 76 cases. Cancer 1972;30(3):726–736 2. Wu CT, Inwards CY, O′Laughlin S, Rock MG, Beabout JW, Unni KK. Chondromyxoid fibroma of bone: a clinicopathologic review of 278 cases. Hum Pathol 1998;29(5):438–446 3. Baujat B, Attal P, Racy E, et al. Chondromyxoid fibroma of the nasal bone with extension into the frontal and ethmoidal sinuses: report of one case and a review of the literature. Am J Otolaryngol 2001;22(2):150–153 4. Koay CB, Freeland AP, Athanasou NA. Chondromyxoid fibroma of the nasal bone with extension into the frontal and ethmoidal sinuses. J Laryngol Otol 1995;109(3):258–261 5. Nazeer T, Ro JY, Varma DG, de la Hermosa JR, Ayala AG. Chondromyxoid fibroma of paranasal sinuses: report of two cases presenting with nasal obstruction. Skeletal Radiol 1996;25(8):779–782 6. Curtin H, Rabinov J, Som P. Central skull base: embryology, anatomy and pathology. In: Som P, Curtin H, eds. Head and Neck Imaging. 4th ed. St Louis: Mosby; 2003:821 7. Keel SB, Bhan AK, Liebsch NJ, Rosenberg AE. Chondromyxoid fibroma of the skull base: a tumor which may be confused with chordoma and chondrosarcoma. A report of three cases and review of the literature. Am J Surg Pathol 1997;21(5):577–582 8. Shek TW, Peh WC, Leung G. Chondromyxoid fibroma of skull base: a tumour prone to local recurrence. J Laryngol Otol 1999;113(4):380–385 9. Isenberg SF. Endoscopic removal of chondromyxoid fibroma of the ethmoid sinus. Am J Otolaryngol 1995;16(3):205–208Chondrosarcoma
Definition
(ICD-O code 9220/3)
Chondrosarcoma is a rare malignant tumor of hyaline cartilage.
Etiology
Previous trauma (accidental or surgical) has been implicated in the development of chondrosarcoma, as has inhalation of hydrocarbons, although these theories are generally discredited.1,2 Chondrosarcomas have been reported to occur in association with other malignant conditions such as osteosarcoma, malignant melanoma, fibrosarcoma, and leukemia, as well as benign conditions such as Paget′s disease and fibrous dysplasia.3,4 They have also been associated with Maffucci′s syndrome,5 multiple hereditary exostosis, previous irradiation, and previous use of intravenous thorium dioxide contrast.6
Mutational inactivation of tumor suppressor genes p16, Rb, and p53 has been implicated in tumor development. Inactivation of p53 has been associated with higher-grade tumors with a worse prognosis, and both Rb and p53 mutations have been linked to chondrosarcoma and osteosarcoma.7
Synonyms
Aggressive cartilaginous tumors were described by Morgan in 1836 and Heath in 1887.8,9 Mollison reported the first chondrosarcoma in the paranasal sinuses in 1916, but it was not until 1939 that Ewing identified chondrosarcoma as a separate entity from osteogenic sarcoma.10,11
Incidence
Chondrosarcomas constitute ~10 to 20% of all malignant bone tumors, and most commonly arise in long bones and the pelvis.2,6,12 Between 3% and 10% of all chondrosarcomas arise in the head and neck6,13,14; skull base chondrosarcomas constitute 0.15% of all intracranial and 6% of all skull base tumors.15 Chondrosarcomas account for less than 16% of all sarcomas of the nasal cavity, paranasal sinuses, and nasopharynx and comprise 3 to 5% of nonepithelial sinonasal tumors. In our own series, chondrosarcomas comprise 34 of 1,063 malignant sinonasal tumors (3.2%).
Site
In 1979, Myers and Thawley classified chondrosarcomas into primary, secondary, and mesenchymal subtypes.16 Primary chondrosarcomas arise de novo from undifferentiated perichondrial cells; secondary ones arise within a preexisting cartilaginous lesion such as a chondroma or exostosis; and mesenchymal ones arise from primitive mesenchymal cells.16 Primary chondrosarcomas may arise within cartilage or in bone that ossified in cartilage such as the sphenoid. However, they can also arise in soft tissues with no obvious cartilaginous source, and this has been suggested to be the result of embryonal cell rests that have escaped resorption, from ectopic chondroid precursor cells or from cartilaginous differentiation of primitive mesenchymal cells.2,14,17,18 This may also account for apparent multisite origins.
Classical chondrosarcomas involve the alveolar portion of the maxilla, the maxillary sinus, the nasal septum, the sphenopetrous area, and the clivus, where the disease may be multifocal. Indeed clinical experience suggests that many sinonasal cases are multifocal. From the nasal septum, the tumor can infiltrate superiorly into the skull base or inferiorly into the palate. They also occur in the larynx and cervical vertebrae.4,6,13,19,20
Diagnostic Features
Clinical Features
In the literature patients’ ages range from 16 months to 89 years,21,22 but the majority of patents are in their fourth and fifth decades with a mean of 46 years,4,13,19,22–25 making this a younger group than for some other sinonasal tumors and chondrosarcomas elsewhere. This has also been the experience in our series, where in 38 individuals the age ranged from 5 to 76 years, with a mean of 42 years. When chondrosarcoma is reported in children20 it must be distinguished from the mesenchymal variant (see below).
The male-to-female ratio varies widely from series to series. The American College of Surgeons’ National Cancer Database reported that 64.5% of sinonasal chondrosarcomas occurred in women,2 which is in keeping with an analysis of 125 cases done by Harrison and Lund in 199326 that showed a ratio of 1:1.2 of men to women. In our own series, a similar male-to-female ratio of 1:1.5 was found. A racial predilection for chondrosarcomas has not been generally found, but the same American Cancer Database reported that mesenchymal and myxoid subtypes are more common in Hispanic (44.9%) and African-American (31.8%) patients than in white patients (17.1%).2
Initially a mass effect produces nasal obstruction and/or epistaxis, which may be bilateral when the septum is affected (68% in our series).22,27,28 Endoscopic examination of the nose can show a smooth swelling covered by normal mucosa (Fig. 11.3). Pain has been reported in less than 50%; swelling of the face and palate may be evident particularly if the tumor is located in the anterior maxilla;13,29 and loosening of teeth can occur.
Once the tumor involves the skull base, various neurologic sequelae can occur, especially with recurrences.6,14,22 The orbit may be involved, producing proptosis and sometimes diplopia; and there can be substantial space-occupying intracranial lesions and cranial nerve palsies.4,6,22,28 Notably, the optic nerve may be compressed, leading to visual loss; and it is not uncommon for the chiasm and both optic nerves to be affected, leading to bilateral blindness. This has occurred in 2 of our patients (6%) (Figs. 11.4, 11.5a,b).
Imaging
Contrast-enhanced CT typically shows a lobulated mass with an irregular matrix containing areas of calcification in ~75%.4,30 The calcification may be punctate, dystrophic, or in a ring and arc pattern.31 There is often bony expansion and erosion.4 The majority of cases involve the nasoethmoid area and are often centrally located. Two-thirds affect the orbit and two-thirds show intracranial extension in our series (Fig. 11.6a and Fig. 11.7a).
Magnetic resonance imaging typically shows a heterogeneous enhancing mass of low intensity on T1W images and high intensity on T2 weighting due to the high water content of the chondroid matrix.6,14 After gadolinium enhancement, T1W images show diagnostic contrast enhancement at the periphery and along fibrovascular septa within an otherwise nonenhancing chondromatous core (Figs. 11.5b, 11.6b, 11.7b).4,30 This can produce a cystic appearance that may be overlooked by the unwary, particularly if MRI alone is being used for follow-up (Fig. 11.5c). It has been our practice to use regular MRI for routine postoperative surveillance but to perform a baseline CT after the initial surgery in cases of chondrosarcoma and to repeat this if the MRI shows any suspicious change (Fig. 11.6c, 11.7c).
Chondrosarcoma must be distinguished from chondroma, meningioma, osteoma, osteosarcoma, osteoblastoma, fibro-osseous lesions, and chordoma.6,32 Occasionally the tumor may be densely calcified with a “sunray” effect, more commonly seen in osteosarcoma.6,14,33
Chondrosarcoma of the nasal septum has also been reported as an incidental finding on CT scanning.32
Histological Features and Differential Diagnosis
The tumors are usually lobulated and firm with a gray-pink glistening granular or “ripe pear” surface. It can be quite difficult to distinguish tumor from normal cartilage, so microscopic criteria were defined by Lichtenstein and Jaffe in 1942: namely, hypercellularity, hyperchromatism or irregularity of nuclei, double or multiple nuclei, areas of differentiation compatible with nonspecific sarcoma, marked enlargement of the chondrocytes, or mitotic figures.34
Classification criteria have been described, primarily relating to the degree of cellularity, the nuclear size, and the number of mitoses (grades 1 to 3, or well to poorly differentiated).23 Grade 1 tumors are well differentiated with abundant pale chondroid matrix, clusters of chondrocytes with normal or slightly enlarged nuclei, absent mitoses, and occasional double nuclei. Grade 2 (moderately differentiated) tumors have less matrix and more chondrocytes, with occasional mitoses and slightly enlarged hyperchromatic, multiple nuclei. Grade 3, poorly differentiated chondrosarcomas have a myxoid matrix with irregular chondrocytes and increased cellularity, nuclear pleomorphism, and mitoses.6
Rare histological variants have been described, including mesenchymal chondrosarcoma (see below) and clear cell chondrosarcoma, which accounts for less than 2% of all chondrosarcomas; metastatic renal cell carcinoma should obviously be excluded in these cases.32 Myxoid chondrosarcoma is a more aggressive subtype affecting children with more bony destruction and a t (9;22) translocation not seen in typical chondrosarcoma.35 Dedifferentiated chondrosarcoma is a highly malignant variant.36
Because differentiating chondrosarcoma from chordoma, osteogenic sarcoma, and salivary gland tumors can be difficult, as large a biopsy specimen as possible should be provided. It is worth noting that chondrosarcomas stain positive for S100 protein, while chordomas are positive for S100 and cytokeratin.6 Others have undertaken complex tissue microarray-based comparative analysis to differentiate between chordoma and chondrosarcoma but of the newer markers (brachyury, SOX-9, and podoplanin) have shown only podoplanin to be positive for chondrosarcoma.37
As previously stated all cartilaginous tumors in this area should be regarded as having malignant potential.23,32,38,39 However, these lesions must be distinguished from Ollier disease, which is characterized by benign growths in the metaphyses of bones, some of which may contain atypical cells. We have encountered one patient with this condition, who presented with extensive involvement of the ethmosphenoid and skull base and who underwent craniofacial resection. Four years later she went on to develop multiple systemic lesions when the diagnosis of Ollier disease was confirmed.
Natural History
Sinonasal chondrosarcoma is normally a rather indolent tumor, although less so than in the larynx.2 Nonetheless, its progress locally is inexorable even though metastatic spread to regional lymph nodes is exceptional.
However, late distant metastases have been reported in up to 20% of cases,6,21,32,40 and are being seen more since the advent of surgical techniques such as combined craniofacial resection, which has dramatically improved local control of disease, prolonging survival.41 Metastases tend to be to the lungs, but late bony metastasis has also been reported.25,42
Thus the history is one of multiple local recurrences, and local spread throughout the skull base is the most common cause of death for these patients (in up to 88%)25 and can occur after many years, so that lifelong follow-up is needed.27
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