A Unique Case of Cutaneous Schwannoma With Coexistent Masson's Hemangioma.

Schwannomas (SCHs) are benign neural tumors originating from Schwann cells of the peripheral nerve sheaths. These neoplasms typically exhibit hyalinized vessels with impaired vascular permeability; however, angioma-like features are rare. We report an intriguing case of a cutaneous SCH with unusual vascular changes in a 60-year-old female who presented with a tender nodular lesion on her lower back. Histopathological examination of the excised lesion revealed a schwannoma with a central area of thrombosis and a vascular proliferative lesion consistent with Masson's hemangioma (MH). MH, also known as intravascular papillary endothelial hyperplasia (IPEH), is a rare benign vascular lesion characterized by papillary endothelial hyperplasia and obliterative changes within vascular lumens. Immunohistochemical staining confirmed S100 positivity in the SCH component and highlighted the papillary endothelial lining by ERG (erythroblast transformation-specific regulated gene 1). To our knowledge, this is the first report of a schwannoma harboring MH. This unique case underscores the potential for rare vascular proliferation to arise within otherwise typical SCHs.