Glomangioma of the supra-patellar knee region : Diagnostic and literature insights

Background: Glomangiomas are rare benign vascular tumors arising from the glomus body and account for approximately 1.6% of all soft tissue tumors. They commonly occur in the subungual region, while extradigital involvement, particularly around the knee joint, is extremely rare and often leads to delayed diagnosis due to nonspecific clinical presentation.Aim and Objective: To report a rare case of suprapatellar glomangioma of the knee, emphasizing its diagnostic challenges, radiological and histopathological features, treatment outcome, and to review the available literature on glomus tumors around the knee.Materials and Methods: A 36-year-old male presented with a painful suprapatellar swelling of the left knee with a history of trauma. Clinical examination was followed by radiological evaluation using X-ray, ultrasonography, and MRI. The lesion was treated by wide local excision. Histopathological and immunohistochemical analyses were performed. Postoperative functional outcome was assessed using the Musculoskeletal Tumor Society (MSTS) scoring system. A literature review was conducted using PubMed and Google Scholar.Results: MRI showed a well-defined lesion with hypointense signals on T1-weighted images and hyperintense signals on T2-weighted images. Histopathology revealed vascular channels surrounded by nests of glomus cells, with immunohistochemical positivity for Smooth Muscle Actin and negativity for CD34 and cytokeratin. Postoperatively, the patient showed complete pain relief and progressive functional improvement, with MSTS score improving from 17 preoperatively to 0 at 24 weeks. Follow-up MRI showed no recurrence.Conclusion: Suprapatellar glomangioma is a rare cause of chronic knee pain. Awareness of this entity, combined with MRI and confirmatory histopathology, is essential for accurate diagnosis and effective surgical management.