Ancient schwannoma of the orbit

Abstract

The ancient schwannoma is a rare variant of a neurilemoma with a course typical of a slow-growing benign neoplasm. Histologically, it can be confused with a malignant mesenchymal tumor because of increased cellularity, nuclear pleomorphism, and hyperchromatism. Despite the degree of nuclear atypia, mitotic figures are absent. We describe the clinical and histopathologic features of an ancient schwannoma of the orbit. A need for early removal of such tumors is recommended to prevent complications.

An Unusual Differential Diagnosis of Orbital Cavernous Hemangioma: Ancient Schwannoma

“…There are no clinical or radiographic pathognomonic features differentiating schwannomas from other well-circumscribed orbital lesions such as cavernous hemangioma, fibrous histiocytoma, neurofibroma, hemangiopericytoma, solitary fibrous tumor, and others. A definitive diagnosis can only be made on histopathology [ 4 , 5 , 6 , 7 , 8 , 9 , 10 ]. Histopathological examination reveals that schwannomas are characterized by hypercellular (Antoni A) and hypocellular (Antoni B) areas.…”

“…Immunohistochemical testing is usually positive for vimentin, neuron-specific enolase, and S-100 protein and negative for cytokeratin [ 2 , 4 , 7 , 10 ]. Degenerative findings such as hemorrhage, cyst formation, focal calcification, and perivascular hyalinization are indicative of the long duration of the tumor and are characteristic of the so-called “ancient schwannomas” [ 2 , 3 , 4 , 5 , 6 , 7 , 10 ]. The hypercellularity and nuclear atypia frequently present in ancient schwannomas may lead to the erroneous interpretation of a malignant tumor [ 2 , 10 ].…”

“…The hypercellularity and nuclear atypia frequently present in ancient schwannomas may lead to the erroneous interpretation of a malignant tumor [ 2 , 10 ]. Complete surgical excision was curative in all reported cases and malignant change was never seen in ancient orbital schwannomas [ 2 , 3 , 4 , 5 , 6 , 7 , 9 ].…”

“…The ancient schwannoma is a rare variant of schwannoma with a typical slow-growing benign course and particular histopathological features. We detected only 6 cases of these tumors in the literature [ 2 , 3 , 4 , 5 , 6 , 7 ] (Table 1 ). The literature search was performed on the MEDLINE database using the keywords “schwannoma,” “ancient schwannoma,” “neurilemmoma,” and “orbit.” Only articles in English were included.…”