Surgical resection of locally advanced granular cell tumor of the orbit

We report a case of locally advanced granular cell tumor of the orbit treated by a multidisciplinary surgical approach. A 49-year-old woman with a recently biopsied granular cell tumor of the orbit was referred to our tertiary care cancer center for evaluation of a right-sided globe ptosis and a palpable mass in the right orbit that had been present for approximately two years. Magnetic resonance imaging showed a large orbital mass that extended posteriorly to the orbital apex and anteriorly to the levator and superior rectus muscle complex. A workup including computed tomography of the chest, abdomen, and pelvis did not show any metastatic foci. Surgical resection of the mass was undertaken via a frontozygomatic craniotomy supplemented by an anterior orbitotomy to repair the levator aponeurosis and the superior oblique tendon, which were partially resected with the mass. Histologic evaluation of the mass revealed solid nests of polygonal cells that had centrally located, round nuclei with abundant eosinophilic granular cytoplasm. The cytoplasmic granules were positive on the periodic acid-Schiff reaction and were diastase-resistant. Immunohistochemical staining was positive for S-100 protein. During the most recent follow-up visit six months after surgery, the patient had no clinical evidence of tumor recurrence, had minimal residual ptosis and exposure keratopathy, and had stable visual function.