A glomus tumor anterior to the patellar tendon: a case report.

Glomus tumors are benign neoplasms originating from the glomus body. They are most frequently found in the nail bed of the hands, and their occurrence in other parts of the body is rare. A 75-year-old man presented with left anterior knee pain of 30-year history, that became more intense with light touch or clothing and increased in severity despite medical treatment. Physical examination showed a painful, soft, mobile, red-purple colored mass, 2 x 2 cm in size, at the inferior border of the patella. Plain radiographs showed no pathology other than mild degenerative changes. Magnetic resonance imaging revealed a mass lesion, 1.5 x 1.1 x 2 cm in size, located at the anterior border of the patellar tendon, which showed hypointensity on T1A-weighted sequences and hyperintensity on T2-weighted sequences and T2-weighted sequences with fat saturation. The mass was excised and the histopathological diagnosis was reported as glomangioma. Postoperatively, the patient had no complaint of pain and no recurrence was observed during a two-year follow-up.