Atypical glomus tumor arising in the liver: a case report

Katsutoshi Hirose, Takahiro Matsui, Hiroaki Nagano, Hidetoshi Eguchi, Shigeru Marubashi, Hiroshi Wada, Eiichi Morii

Glomus tumors typically occur in the subcutaneous tissue of distal extremities, but rarely in visceral organs. Most glomus tumors are benign, while others have been reported to have malignant potential. Herein, a unique case of a liver glomus tumor with atypical histological features is reported. A 39-year-old man felt fullness in the epigastrium, and an enhanced computed tomography (CT) scan of the abdomen and pelvis revealed a 21-cm solid and cystic mass in the left liver lobe. The patient underwent a left hepatic lobectomy, and the tumor was pathologically identified as a glomus tumor with atypical histological features in the liver. This case is unique for three reasons. First, cases of glomus tumors in the liver are extremely rare. Second, this is the first report of a hepatic glomus tumor with histologically atypical features. Third, immunohistochemical staining showed focal positivity for synaptophysin. A literature review revealed that glomus tumors in visceral organs positive for synaptophysin show histological atypical features in most cases. This is the first case of a glomus tumor with atypical histological features arising in the liver. This unique case and literature review yielded interesting findings and enabled us to postulate that synaptophysin positivity may be indicative of atypical histological features in glomus tumors arising in visceral organs.