Spindle cell lipoma of the orbit.

A spindle cell lipoma was partially removed from the left orbit of a 27-year-old man. Computed tomography showed a large, mildly enhancing, primarily intraconal mass. The circumscribed, nonencapsulated mass was composed of mature adult lipocytes, spindle cells, and capillaries. The spindle cells lacked a basal lamina and contained a single elongated nucleus. Cells containing osmiophilic material were rounded with nucleus displaced to one margin. Because of the tumor's size and proximity to vital structures, total excision was not possible. Such tumors are more frequent in the subcutaneous tissue of the shoulder and posterior aspect of the neck. This benign lesion may be mistaken for other spindle cell tumors, including liposarcoma, angiolipoma, neurilemmoma, and hemangiopericytoma.