A recurrent solitary glomus tumor of the forearm

Glomus tumors account for 1.6% of all soft tissue tumors and the majority are localized at the level of the fingertips and do not exceed the size of 5 mm. They are usually solitary tumors, characterized by the following clinical triad - severe pain, pinpoint tenderness, and cold intolerance. We present the case of a 63-year-old patient with a fixed tumor located in the lower third of the right forearm with a long-axis diameter of 4 cm, with irregular borders and tenderness to palpation. The tumor had been surgically removed 15 years ago, but it redeveloped two months after surgery, and grew in size until the fourth month after the surgery when it stopped growing. The preoperative ultrasound showed an expansive mass suggestive of swelling/inflammation in the adjacent soft tissue and having a mass effect on the deep muscle structures. Intraoperatively, a 3/4/3 cm (antero-posterior∕transversal∕cranio-caudal) pink tumor was found subcutaneously, with well-defined borders, which was mobile on the deep planes, apparently encapsulated. The tumor was removed with safety margins of about 1 cm and hemostasis was performed. Postoperatively, immunohistochemistry confirmed the diagnosis of glomus tumor: alpha-smooth muscle actin (α-SMA) positive in the cytoplasm of malignant cells, type IV collagen positive in the basement membrane, cluster of differentiation 34 (CD34) negative in the malignant cells, CD34 positive in endothelial cells, Ki67 positive in the 1-2% of the cancer cells nuclei. The postoperative evolution was favorable, without complications and no recurrence at six months.