Malignant Lymphoma
Patients with orbital lymphomas are usually 50 to 60 years old and present insidiously with proptosis and, frequently, a rubbery fleshy mass under the bulbar conjunctiva or eyelids (Figure 10-5). CT scan may show that the tumor conforms to the contours of the eye (Figure 10-6). Fine needle aspiration reveals abundant cellular material with a relatively homogenous population of lymphocytes (Figure 10-7). Orbital lymphomas are similar to other extranodal non-Hodgkin lymphomas. They are usually diffuse and of B-cell lineage.
Although histologic patterns of the diffuse and nodular lymphoma cannot be discerned from aspiration smears, B- and T-cell marker studies can be done (Figure 10-8). [
22] The prognosis of orbital lymphomas may be better determined by location and involvement of other sites than histologic classification and marker studies. [
23,
24]
Idiopathic Orbital Inflammation (Sclerosing Orbititis)
Idiopathic orbital inflammation is also referred to as inflammatory pseudotumor. It may present acutely or in a chronic form. In the acute form, there is an abrupt onset of pain, injection, chemosis, and decreased ocular motility. The inflammation involves orbital soft tissues including fat, extraocular muscle, tendon, lacrimal gland, and blood vessels. [25,
26] Sclera may be inflamed in late cases. [
27] In the chronic form, there is marked fibrosis that may envelop the structures of the orbit and mimic a malignant neoplasm. The diagnosis often can be made clinically, but occasionally a fine needle aspiration biopsy will be requested. It is extremely difficult to get adequate material to diagnose chronic sclerosing orbititis. Usually, scant aspirates with a few fibroblasts and lymphocytes will be identified (Figure 10-9).
