Subcutaneous Schwannoma on the leg with hemorrhagic cystic degeneration:a case report

A 64-year-old female with a subcutaneous schwannoma accompanied by hemorrhagic cystic degeneration in the left lower extremity. The patient presented with a progressively enlarging subcutaneous mass over an 8-year course, accompanied by activity-induced dull pain. Physical examination revealed a firm, well-defined nodule measuring 5.0 × 3.5 × 0.5 cm, with a negative Tinel sign. Microscopic analysis demonstrated characteristic Antoni A areas and Antoni B. Subcutaneous schwannomas are prone to misdiagnosis due to the absence of typical imaging features, necessitating a multidimensional analysis integrating clinical manifestations, imaging findings, and histopathological features for accurate identification and differential diagnosis. Radical resection with a surgical margin ≥5 mm achieved cure, and no recurrence was observed during the 4-year follow-up. This case highlights the importance of considering schwannoma in the differential diagnosis of chronic subcutaneous lower extremity masses. Establishing a "clinical-imaging-pathological" tripartite diagnostic framework is critical for early and precise management.