Rare presentation of a primary intraosseous glomus tumor in the humerus of a teenager.

A glomus tumor is a benign mesenchymal tumor comprised of cells that resemble the perivascular modified smooth muscle cells of the glomus body. Glomus tumors typically appear in the superficial lesions of the soft tissue in the extremities, such as the subungual region. However, their occurrence in the bone is rare, with only about 30 cases reported to date. Half of these cases involved the distal phalanges of the fingers or toes, with only three reported cases involving the long bones. Here, we present the first case, a primary glomus tumor in the humerus of a 14-year-old female. An osteolytic and cystic lesion was detected after a pathological fracture occurred during exercise. Despite the tumor's large size, no pathological findings indicated malignancy. The fracture healed through conservative treatment, while the tumor was effectively managed with curettage. Appropriate medical care can be provided to patients by focusing on pathological findings.