Adrenal Schwannoma: A Rare Type of Adrenal Incidentaloma

Adrenal schwannoma is a rare type of adrenal incidentaloma, an adrenal lesion found incidentally, usually on imaging or autopsy. Computed tomography and magnetic resonance imaging are tools used to evaluate adrenal lesions. The diagnosis of adrenal schwannoma, however, cannot be made on imaging alone. Surgical resection is the primary means of management of adrenal schwannomas, as it is not possible to distinguish the schwannoma from malignant entities simply based on imaging. Histopathologic features of adrenal schwannomas are similar to those of schwannomas found at other sites. Conventional schwannomas, consisting of alternating Antoni A and Antoni B areas as well as Verocay bodies, have distinct microscopic features and can be readily distinguished from other entities. Cellular schwannomas, on the other hand, consist only of intersecting fascicles of spindle cells or Antoni A areas, resulting in a wide differential diagnosis. Ancillary studies such as immunohistochemical analysis and electron microscopy can help to provide a specific diagnosis.