Persistent Thrombotic Hemangioma With Organizing/Anastomosing Features: A Case Report of a Guanine Nucleotide-Binding Protein Alpha Subunit (GNA)-Mutated Cutaneous Vascular Lesion.

Thrombotic hemangioma with organizing/anastomosing features (THOA) is a newly identified variant within the spectrum of hemangiomas that harbor mutations in the guanine nucleotide-binding protein alpha subunit (GNA) genes (like GNAQ or GNA11). While THOA shares similarities with anastomosing hemangioma, it possesses distinct clinical and morphological characteristics that make it a separate entity. All reported cases of THOA have demonstrated benign behavior. However, histologic features such as anastomosing vascular growth, mitotic figures, and endothelial hobnailing may raise concerns for a low-grade malignant vascular neoplasm. We report the case of a 74-year-old female with an unremarkable medical history who presented with a vascular lesion on her upper torso. The lesion persisted after the initial biopsy and was re-excised, displaying similar histologic characteristics. Next-generation sequencing (NGS) revealed a GNAQ mutation (p.Q209H) in both samples. Notably, a TP53 mutation (p.R273H) was detected in the first specimen but was absent in the subsequent excision. The lesion was diagnosed as persistent THOA. This case report discusses the salient features, genetic profile, and prognosis of this uncommon lesion.

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.