Cutaneous microcystic/reticular schwannoma: case report and literature review of an exceedingly rare entity with an unusual presentation.

Conventional schwannoma represents a benign peripheral nerve sheath tumor derived from Schwann cells, which usually arises in the fourth or fifth decade of life, in the subcutaneous tissue of the distal extremities, or in the head and neck region of adult patients, with no gender predilection. In addition to the classic type, at least 11 different histopathological subtypes have been described and unawareness of these uncommon histopathological entities may lead to diagnostic pitfalls and risk of mistreatment. Recently described in the scientific literature, microcystic/reticular schwannoma is still relatively unknown to both surgeons and pathologists. The purpose of this paper is to highlight its existence by describing an additional case that occurred in the retroauricular area, and to further characterize its clinical, histopathological and immunohistochemical features. We reviewed the literature and compared the current case with others that have been documented thus far, discussing all possible differential diagnoses.