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 lowgrade 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.