The orbit is an anatomically complex structure containing the globe, extraocular muscles, fat, and vascular, nerve, glandular, and connective tissues.
Orbital tumors can be benign or malignant and arise primarily within the orbit or secondarily from an adjacent source, such as the eyelid, paranasal sinus, or intracranial compartment. Orbital tumors can also be metastatic from distant sites.
Some types of orbital tumors usually cause proptosis and displacement of the globe in a direction opposite the tumor. Pain, diplopia, and vision loss may also be present. The diagnosis of orbital tumors is suspected based on the history, examination, and neuroimaging (CT, MRI, or both), but confirmation often ultimately requires a biopsy. Causes and treatment vary by age group.
Benign pediatric tumors are most commonly dermoid tumors and vascular lesions such as capillary hemangioma and lymphangioma.
Treatment of dermoid tumors is excision.
Capillary hemangiomas tend to spontaneously involute and therefore usually do not need any treatment. However, especially when located on the upper eyelid, they may affect vision and require treatment with systemic beta-blockers.
Small lymphangiomas that do not cause symptoms may be followed clinically. For larger lymphangiomas or those that are causing symptoms, options include surgical debulking, intralesional sclerotherapy, and, in some cases, sildenafil.
Malignant pediatric tumors are most commonly rhabdomyosarcoma and metastatic lesions related to leukemia or neuroblastoma.
If rhabdomyosarcoma is resectable, surgery is done, followed by chemotherapy and orbital radiation therapy.
Leukemic disease is usually managed by orbital radiation therapy, chemotherapy, or both.
Benign adult tumors are most commonly meningiomas, mucoceles, and cavernous venous malformations (also known as cavernous hemangiomas). Pleomorphic adenomas of the lacrimal gland are less common.
When symptomatic, sphenoid wing meningiomas are treated with debulking via craniotomy, sometimes followed by a course of radiation therapy. Because meningioma cells infiltrate bone of the skull base, complete resection usually is not possible.
Mucoceles are treated by draining them into the nose because they most commonly arise from the ethmoid or frontal sinus.
Cavernous venous malformations and lacrimal gland pleomorphic adenomas are excised.
Malignant adult tumors are most commonly lymphoma, squamous cell carcinoma, and metastatic disease. Less commonly, the tumor is an adenoid cystic carcinoma of the lacrimal gland, which is an aggressive tumor.
Lymphomas involving the orbit are typically B-cell and characteristically low grade. Lymphomas can be bilateral and simultaneous and can be part of a systemic process or exist in the orbit in isolation. Radiation therapy effectively treats orbital lymphomas with few adverse effects, but treatment with monoclonal antibodies against a surface receptor (CD20) on the lymphocyte is also effective and should be considered in addition to or instead of radiation therapy, particularly if lymphoma is systemic.
Most squamous cell carcinomas arise from the adjacent paranasal sinuses. Surgery, radiation therapy, or both form the backbone of therapy.
Metastatic disease is usually treated with radiation therapy. Metastatic disease involving the orbit is usually an unfavorable prognostic sign; carcinoid tumors are a notable exception.
Lacrimal gland adenoid cystic carcinoma is treated with surgery and then usually with radiation therapy (sometimes proton beam therapy) or by a protocol using intra-arterial chemotherapy with radiation therapy and surgery.