Orbital neoplasms constitute 20 to 25% of all orbital diseases. Primary orbital neoplasms are less common than secondary masses that arise from adjacent periorbital and other structures. They comprise a range of benign and malignant diseases that can be either space occupying or infiltrative. They may arise from cells of bony, vascular, muscular, neural, lymphoid, or connective tissue origin. Primary tumors within the orbit may be categorized according to the tissue of origin, location, and benign or malignant behavior. The most common neoplasms seen are of vasculogenic, cystic, and lymphocytic origin. Orbital neoplastic diseases can cause widely variable symptoms, depending on their growth patterns and characteristics ( ▶ Table 12.1). Since the orbit is anatomically unique, with many important structures packed into a relatively tight space, tumor location imparts particular significance in its clinical sequelae and thus its management. A complete ophthalmic examination should be documented for all patients with an orbital mass. This should include measurement of visual acuity, confrontation visual fields, pupils, intraocular pressure, extraocular motility, exophthalmometry, color vision, and a slit-lamp anterior segment as well as dilated fundus examination. The presence of orbital pathology should prompt formal visual field testing and consideration of nerve optical coherence tomography (OCT). Documenting a thorough patient history and clinical examination should also focus on elements that may help characterize the mass and narrow the differential diagnosis. Proptosis is measureable using an exophthalmometer such as a Hertel device, and should also be clinically characterized by noting whether the patient exhibits axial or abaxial proptosis. Pain should be noted, as this may indicate perineural invasion of the tumor. Periorbital signs such as erythema, swelling of eyelid or conjunctival tissue, telangiectasis or vascular dilatation, or pain to touch may point to inflammatory lesions. Palpable resistance to retropulsion of the globe or a palpable periorbital mass should be documented. Timing of progression of symptoms and signs, if present, should be recorded. Rapidity of onset points toward inflammatory, infectious, or traumatic etiologies, while slower onset over months is more characteristic of slow-growing tumors.
Pain and/or restriction with eye movement
Resistance to globe retropulsion
Cranial nerve V1 or V2 numbness
Decreased vision of visual field
Asymmetric periocular edema or erythema
12.2 Lymphocytic and Leukemic Lesions
12.2.1 Ocular Adnexal Lymphoma
Lymphomas arising in the orbit, lacrimal gland, eyelids, or conjunctiva are termed ocular adnexal lymphoma (OAL). The vast majority of these are primary extranodal tumors, although a minority develop secondary to disseminated diseases. These tumors are almost always extranodal non-Hodgkin’s lymphoma (NHL), comprising about 2% of all NHL. The most common subtype is extramarginal zone B-cell lymphoma (EMZL), sometimes called MALToma because it arises from mucosa-associated lymphoid tissue. EMZL accounts for 80% of OAL, followed by follicular lymphoma and diffuse large B-cell lymphoma (DLBCL). The remainder are rare and include mantle cell, small lymphocytic, and lymphoplasmacytic lymphoma. 1, 2 Only a handful of primary T-cell lymphoma and Hodgkin’s lymphoma cases have been documented. Although often focal, OAL may be bilateral or multicentric or disseminate via the regional lymph nodes. These tumors tend to mold to adjacent structures, only invading into adjoining bone and involving the sinuses or intracranial contents in advanced cases. Risk factors include immunosuppression and ultraviolet irradiation, as well as chronic antigen stimulation with inflammation and possibly infection with Chlamydia psittaci. 3, 4 Patients typically present in the sixth or seventh decade with a less than a year history of painless eyelid or orbital swelling and proptosis. No sex predilection has been reported. Examination may reveal a pink, “salmon-patch” lesion of the conjunctiva in conjunctival lymphoma ( ▶ Fig. 12.1). Orbital computed tomography (CT) or magnetic resonance imaging (MRI) with contrast should be ordered to delineate the extent of the tumor. CT scan will demonstrate a homogeneously enhancing, well-circumscribed mass that molds to surrounding structures. Bone erosion is not typical. On MRI, lymphoma is usually isointense to the extraocular muscles on T1 and T2 phases and enhances with gadolinium. 4 If lymphoma is suspected, a biopsy should be performed, with tissue sent both in formalin and fresh for flow cytometry. Once the diagnosis is confirmed, positron emission tomography CT (PET-CT) of the chest, abdomen, and pelvis should be performed to evaluate for metastases and stage the disease. Blood testing including complete blood count, protein electrophoresis, lactate dehydrogenase, beta-2-microglobulin levels, complete metabolic panel, hepatitis C and HIV testing, and bone marrow evaluation are typically performed by the oncologist. Isolated orbital lesions may be treated with irradiation or systemic chemotherapy, while systemic involvement requires chemotherapy/immunotherapy. Prognosis varies depending on the lymphoma subtype. EMZL has a generally good prognosis, with 90% survival in the long term, unless certain factors, such as aggressive histologic subtype, advanced age, and systemic dissemination, are present. Mantle cell lymphoma is more aggressive, with overall disease-free survival of only 50% at 5 years, although survival has improved with rituximab-based regimens. 5 Follicular lymphoma is typically also aggressively treated, as transformation to DLBCL may occur. Radiotherapy is the treatment of choice, with addition of chemotherapy if DLBCL is present. 6 Follicular lymphoma has an overall mortality rate of about 25%, while DLBCL has about 45% mortality rate. T- and NK-cell lymphomas are very rare as primary orbital lesions. They are much more aggressive and may have up to 100% mortality.
Fig. 12.1 Classic “salmon-patch” appearance of a conjunctival lymphoma.
12.2.2 Idiopathic Orbital Inflammation
Idiopathic orbital inflammation (IOI), also termed orbital pseudotumor, as well as reactive lymphoid hyperplasia, lies on the benign end of the lymphoproliferative spectrum of orbital lesions. They deserve special mention because these lesions are seen fairly often and may be mistaken for malignant lymphoma or, if the extraocular muscles are primarily involved, may be confused with thyroid eye disease. These lesions often present with rapidly progressive orbital inflammatory signs, including eyelid edema and erythema, conjunctival chemosis and hyperemia, and sometimes severe orbital pain ( ▶ Fig. 12.2). Progressive inflammation may cause restrictive strabismus with associated diplopia, proptosis, ocular hypertension, and even vision loss. Diagnostic workup includes testing to rule out associated systemic disease including ESR (erythrocyte sedimentation rate), CRP (C-reactive protein), and selective serologic testing depending on review of systems. First-line treatment is high-dose oral corticosteroids with a slow taper. In cases with optic neuropathy, urgent intervention may be required, including use of IV (intravenous) corticosteroids or surgical decompression. Masses that respond poorly to steroids should be biopsied. If the diagnosis of IOI is confirmed, and there is poor response to corticosteroid therapy, alternative treatments may be considered such as rituximab or other immune modulatory drugs, or external beam radiation therapy.
Fig. 12.2 Nonspecific orbital inflammation of the right lacrimal gland. (a) Periorbital erythema, edema, and ptosis. (b) Axial noncontrast CT (computed tomography) showing enlarged right lacrimal gland and overlying eyelid edema.
12.2.3 Orbital Leukemia
Leukemia in childhood may occasionally involve the orbit due to extension from involvement of surrounding structures. The two most frequent subtypes are acute lymphoblastic leukemia and acute myelogenous leukemia. Leukemic orbital lesions are also known as granulocytic sarcoma, myeloblastoma, myeloid sarcoma, or chloroma. Children may present with acute onset of proptosis and eyelid swelling that may be mistaken for orbital cellulitis. Neuroimaging of the orbit should be performed, which will show a homogeneous, mildly enhancing mass without bone erosion. 7 Biopsy should be performed and once the diagnosis is confirmed, treatment is nonsurgical, with chemoradiation by an oncologist.
12.3 Vasculogenic Neoplasms
12.3.1 Infantile Hemangioma
Capillary hemangiomas, also called infantile hemangiomas, are the most common benign vascular pediatric tumors of the orbit. Infantile hemangiomas are congenital hamartomas that progress through an initial proliferative phase during which lesions grow most rapidly, then enter an involutional phase during which the lesions often regress significantly. Infantile hemangiomas present within and grow over the first year of life, and typically regress from 1 to 5 years of age. 8 Superficial hemangiomas typically present as reddish, elevated skin lesions, while deeper hemangiomas appear bluish or violaceous. They are most commonly seen in the superior orbit or upper eyelid. If large enough to cause amblyopia from mechanical ptosis or other etiologies such as induced astigmatism, treatment is indicated. Smaller lesions that are not amblyogenic may be observed without treatment. If found to be very large or involve adjacent facial areas, workup should be performed for the PHACE (posterior fossa malformation, facial hemangioma, arterial lesion, cardiac anomalies, eye abnormalities) syndrome.
Diagnostic evaluation by ultrasound or MRI of the orbits may be performed to confirm a suspected diagnosis and define the extent of the lesion in order to plan treatment. CT imaging should be avoided in young children due to the risks of radiation. Infantile hemangiomas have variable features on neuroimaging, with some lesions appearing more well defined and others poorly defined, and they may appear across multiple spaces within the orbit and lids. They enhance with contrast on MRI scans, and appear heterogeneous on T1- and T2-weighted imaging. 4
First-line treatment involves beta blockers such as propranolol, which can be administered orally or, if there is a superficial orbital/eyelid component, topically in the form of timolol gel. 9 Timolol topical treatment has been shown in a handful of small case series to induce regression in even deeper orbital infantile hemangiomas. 10 Beta blocker treatment may be complicated by bradycardia, hypoglycemia, hypotension, or bronchospasm and should be closely supervised by a pediatrician. Alternative treatments include use of pulsed-dye laser, Nd:YAG (neodymium:yttrium aluminum garnet) laser, irradiation, interferon alpha-2, and oral or injectable corticosteroids. 11, 12 Treatment is continued as long as the lesion is large enough to cause amblyopia. Surgery is only rarely indicated for capillary hemangiomas refractory to medical treatment that are threatening the vision.
12.3.2 Cavernous Hemangioma
Cavernous hemangiomas are the most common benign primary orbital tumors in adults. These tumors typically appear between 20 and 60 years of age with a female predominance, and present as painless, slowly progressive proptosis over months to years. They are composed of large vascular spaces separated by fibrous septa surrounded by a pseudocapsule. 4 The majority of these lesions lie intraconally, although larger lesions may extend extraconally. Tumors are typically detected either incidentally, on neuroimaging performed for unrelated reasons, or when the hemangioma is large enough to cause discernable proptosis, visual disturbance, or diplopia. Vision changes may include hyperopic shift, binocular gaze-induced diplopia, visual field deficit gaze-evoked amaurosis secondary to optic nerve compression, or loss of visual acuity. Diagnosis requires orbital imaging. CT and MRI with contrast demonstrate a well-circumscribed lesion that enhances diffusely with a mottled pattern and may rarely contain hyperdense flecks of intralesional calcification. 13 The tumors can be observed unless visual disturbance is significant enough to justify surgery, at which point complete surgical excision is indicated. 14
Lymphangiomas are congenital lymphovascular choristomatous malformations that typically present within the first two decades of life with painless, progressive proptosis that may be rapid or insidious ( ▶ Fig. 12.3). Rapid onset of proptosis may occur with an episode of intralesional hemorrhage, which can be posttraumatic or spontaneous. Enlargement of lesions can also occur rapidly during upper respiratory infection. Significant enlargement may cause pain, extraocular motility restriction with diplopia, compressive optic neuropathy, and vision loss. These malformations are infiltrative and may be present in both the intraconal and extraconal spaces with extension superficially into the eyelids or conjunctiva. Workup should include a thorough review of systems as there may be multiple lesions present systemically. Diagnostic orbital imaging should be performed to help verify the diagnosis and extent of lesions. CT imaging will demonstrate a poorly defined, heterogeneously enhancing, multicystic lesion. Fluid–fluid levels and blood of different ages may be identifiable on MRI. The infiltrative nature and risk of significant intraoperative bleeding cause difficulty during attempted surgical resection. Most commonly, lesions are monitored without intervention or treated by a team approach including an interventional radiologist and orbit surgeon. The use of multiple sclerosing agents such as bleomycin, OK-432 (picibanil), onyx, sodium tetradecyl sulfate, ethanol, doxycycline, and others have been described in the literature. Injection of these agents directly into the macro- and microcysts under radiographic guidance is performed and the sclerosant induces collapse of the cyst walls, effectively decreasing the lesion size. 15 A handful of pediatric lymphangiomas have also been successfully treated with oral sildenafil, but larger studies are needed. 16 Surgery should generally be undertaken sparingly given the risk for these tumors to bleed intraoperatively and enlarge aggressively postoperatively. Injection of hardening agents such as cyanoacrylate and Ethiodol into selected lesions prior to resection may lessen hemorrhage during surgery. 17
Fig. 12.3 (a) Orbital lymphangioma presenting with left hypoglobus and proptosis. (b) Sagittal T2-weighted, postcontrast MRI (magnetic resonance imaging) demonstrating a large, heterogeneously enhancing intraorbital mass that crosses the intra- and extraconal space.
Orbital varices are congenital dilated venous channels that may present with progressive proptosis or may be visible and present from birth superficially on the eyelids or ocular surface. These lesions may thrombose, resulting in orbital pain, motility restriction, or, rarely, vision loss. Valsalva maneuver and prone positioning will characteristically cause enlargement and temporarily worsen proptosis. Workup should include diagnostic orbital imaging. CT imaging will show a hyperdense, ovoid, or cylindrical lesion in the orbit that enhances heterogeneously with contrast. MRI demonstrates a lesion that is isointense on T1 imaging and variable intensity on T2 imaging that increases visibly in size with Valsalva during dynamic imaging. 18 Treatment generally involves observation unless there is visual compromise, in which case a combination of surgical drainage and excision is undertaken. 4 In some cases, endovascular embolization or sclerotherapy may be attempted. 19, 20
Other extremely rare vasculogenic orbital lesions include angiosarcoma, Kaposi’s sarcoma, angiomyoma, and hemangioendothelioma.
12.4 Lacrimal Gland Neoplasms
Lacrimal gland lesions comprise 10% of all orbital masses. Of these, 20% are epithelial and the remaining 80% are nonepithelial. About half of primary epithelial lacrimal gland tumors are benign and half are malignant. 21 Malignant epithelial lacrimal gland tumors tend to present in young to middle-aged adults, with equal frequency in men and women. Presenting symptoms may include pain if there is bony or nerve invasion, as well as increasing proptosis, inferotemporal globe displacement, motility restriction, and ptosis over the course of several months.
Benign epithelial lacrimal gland tumors also present with proptosis and inferotemporal globe displacement, but the time course of progression tends to be greater than that in malignant tumors.
Primary lacrimal gland adenocarcinoma is an extremely rare malignant epithelial tumor that presents with an enlarging, firm, nonmobile mass of the superotemporal orbit. Ptosis, hypoglobus, diplopia, and vision changes may occur as the mass enlarges. Pain may occur with perineural invasion. This aggressive neoplasm may have distant metastases or regional invasion upon presentation. Orbital CT and MRI should be performed and will reveal a homogeneously enhancing lacrimal gland mass with poorly defined margins and bony remodeling of the lacrimal gland fossa. 4 Biopsy is performed to confirm the diagnosis, and staging should be performed with PET-CT evaluation for lymph node or distant metastases. Treatment is surgical with wide margins or orbital exenteration, with the addition of neoadjuvant or adjuvant chemotherapy and adjuvant orbital irradiation. However, recurrence rates are high and prognosis for survival is poor.
12.4.2 Adenoid Cystic Carcinoma
Adenoid cystic carcinoma is the most common malignant epithelial tumor of the lacrimal gland, comprising about 60% of primary epithelial lacrimal gland tumors. This rare neoplasm presents typically between ages 40 and 60 years and may have a biphasic age peak with a cohort of patients 25 years younger, without any sex predilection. Patients present with several months of progressive proptosis and hypoglobus with pain due to a high rate of perineural invasion. Ptosis, diplopia, and visual disturbance may occur as the mass enlarges. Orbital imaging should be ordered to identify and further characterize the mass. CT should be reviewed to evaluate for bone invasion and destruction, which occurs frequently, and will demonstrate an irregular lacrimal gland mass that may have flecks of calcification ( ▶ Fig. 12.4). MRI demonstrates an irregularly bordered mass with enhancement with contrast. Anterior orbitotomy with biopsy of the mass should be performed to confirm the diagnosis, followed by rapid referral to an oncologist for staging workup. Treatment modalities are currently quite controversial and are still evolving due to the poor prognosis of this tumor, which confers 20% survival at 10 years. Traditionally, orbital exenteration, followed by irradiation was recommended and is still the most commonly utilized treatment despite not improving survival rates. A newer modification to this protocol that adds neoadjuvant intra-arterial chemotherapy administered via the lacrimal vasculature has been recently espoused. Ten-year data for a series of 19 patients treated with this protocol demonstrated improved survival rates of 50 to 100%. 22
Fig. 12.4 Noncontrast CT (computed tomography) bone windows can help distinguish a malignant from a benign lacrimal gland mass. (a) Adenoid cystic carcinoma of the right lacrimal gland with bony erosion through the orbital roof (asterisk). (b) Benign mixed tumor of the left lacrimal gland with characteristic scalloping of the lacrimal fossa (asterisk). (c) Bosselations visible on the surface of the tumor.