Cutaneous Pseudoglandular Schwannoma: A Case Report of an Unusual Histopathologic Variant

Abstract

Multiple morphologic variants of schwannomas have been described, including plexiform, cellular, epithelioid, ancient, and glandular schwannomas. Very rare variants of schwannoma contain gland-like structures formed by neoplastic Schwann cells. The differential diagnosis in these cases can be challenging and includes adnexal neoplasms, neurothekeoma, and vascular neoplasms. We present a case of a well-circumscribed dermal-based neoplasm, which consisted of microcystic gland-like spaces lined by flat to cuboidal cells. A small focus of spindle cells with features resembling that of the Antoni A area typical of schwannoma was present. By immunohistochemistry, the cells lining the cystic spaces and the rest of the tumor were consistent with Schwann cells. In conjunction with this case report, we shall review the concept of the glandular structures in schwannoma.

Cutaneous Cellular Pseudoglandular Schwannoma

“…1 These variants are considered rare in the skin. Although isolated cases of cutaneous cellular schwannomas and cutaneous pseudoglandular schwannomas have been reported, [2][3][4][5] to our knowledge, this is the first published description of a cutaneous cellular pseudoglandular schwannoma.…”

“…We, along with others, favor that the pseudoglandular formation is an accumulation of proteinaceous fluid and may be due to a degenerative change within the tumor. 3 Cellular schwannoma is a benign tumor with fewer than 5% of cases developing recurrences following excision and no reports of metastases or death. 1 As we consider our case a variant of cellular schwannoma, we recommend complete excision and expect a similar clinical course.…”

Microcystic pseudoglandular plexiform cutaneous neurofibroma

“…Pseudoglandular spaces have to be differentiated from true glandular component. Formation of microcysts with a pseudoepithelial lining of Schwann cells resulting in pseudoglandular elements is considered to be a degenerative change based on the mucinous component as well as the low proliferative index within the areas of cystic change . Pseudoglandular spaces, as well as other degenerative changes such as lipid infiltration, hemorrhagic foci or cystic changes are typically seen in schwannomas.…”

Pseudoglandular schwannoma mimicking alveolar rhabdomyosarcoma: A diagnostic challenge on fine‐needle cytology

“…The histologic picture of PGS show pseudocolumnar or cuboidal‐like neoplastic Schwann cells lining variably sized cystic spaces, which occasionally contain a secretion‐like material . PGS is quite distinct from the somewhat better characterized glandular schwannoma (GS), in which small foci of glands, postulated to be lined by ependymal cells or intestinal or respiratory‐type epithelium, are present . We report a rare case of PGS in a 17‐year‐old adolescent boy with a neck mass 8 cm in diameter present for 2 years with a recent increase in size; the neck mass demonstrated rhabdoid‐like cuboidal cellular features mimicking alveolar rhabdomyosarcoma (ARMS) on fine‐needle aspiration (FNA).…”