Glomus tumors with cystic changes around the ankle

Sizable glomus tumors with cystic changes in the ankle are extremely uncommon. This paper describes painless glomus tumors with cystic changes arising in the ankle of a 22-year-old woman. At the age of 14, a painless mass was noticed on the lateral side of the left ankle, and at age 21, another mass appeared on the medial side of the same ankle. Magnetic resonance imaging (MRI) and computed tomography (CT) scanning revealed 4.5 x 4.0 cm and 2.0 x 2.0 cm sized masses on the medial side and a 3.0 x 4.0 cm sized cystic mass on the lateral side of the ankle. The tumors were removed en bloc. Microscopically, the tumor consisted of perivascularly arranged cells with punched-out, round, and regular nuclei. Immunohistochemically, the tumor cells expressed SMA and HHF-35, indicating smooth muscle cell characters. The patient had no recurrence at 2 years after surgery.