Pathergy of a Medial Heel Schwannoma

Schwannomas are benign soft-tissue tumors derived from Schwann cells of the peripheral nervous system. They typically appear on the head, neck, or trunk, and are often asymptomatic or present with mild tenderness to palpation and numbness due to nerve compression. A 17-year-old male was referred to our dermatology clinic for evaluation and treatment of an asymptomatic, pink, flesh-colored subcutaneous nodule on the medial right heel. A biopsy was performed to rule out malignancy, with the pathology report consistent with the diagnosis of schwannoma. Following the biopsy, the patient developed a persistent, non-healing red-violaceous ulcerative plaque at the biopsy site, which persisted following additional electrodessication and silver nitrate application. Repeat biopsy showed persistent schwannoma and notably the absence of a pyogenic granuloma. The persistent ulceration following the initial biopsy is consistent with the phenomenon known as pathergy, which refers to exaggerated tissue reactivity in response to trauma. The patient eventually required surgical excision and a keystone flap for definitive treatment of the lesion. Although rare, we have demonstrated that pathergy can occur during surgical procedures on suspected schwannomas. Physicians should be aware of this possible complication so that they can provide anticipatory guidance for patients undergoing surgical procedures on undiagnosed cutaneous neoplasms for which a schwannoma is in the differential diagnosis.