A case of hepatic small vessel neoplasm without previously reported hotspot mutation of alpha subfamily of G proteins

Hepatic small vessel neoplasm (HSVN) is a very rare and recently described entity. Moreover, it is a vascular neoplasm of the liver composed of small vessels with infiltrative borders that mimic hepatic angiosarcoma. Based on its lack of atypical morphological features and high proliferative activity, HSVN is thought to be a benign or low-grade neoplasm; however, there is a lack of follow-up information. Here, we present a 51 year-old man with an incidental segment VIII lesion of the liver that displayed plethoric features, which was suspected to be a neoplasm. The patient underwent a segment anterior sectionectomy. The resected liver tumor demonstrated a 2.0 cm by 1.2 cm tan red and partially ill-defined mass, and microscopical examination confirmed HSVN, although the previously identified mutations in HSVN, GNAQ, GNA11, GNA14, and PIK3CA were not detected by genetic testing. The patient’s postoperative recovery was uncomplicated, and abdominal computed tomography at 6 months and 12 months post-surgery revealed no evidence of recurrence. HSVN is a recently described vascular tumor liver with uncertain malignant potential. More research is warranted to establish guidelines for an accurate diagnosis and to elucidate the clinical course of these tumors.