Multiple Penile and Pelvic Schwannomas in an Adult Male: A Case Report

Abstract

Schwannomas are relatively common benign tumours that gradually increase in size and develop in the peripheral nerve sheaths of adults. However, they are exceptionally rare in the penile and pelvic regions. Hereby, the authors present a case report of an extremely rare case of concomitant multiple schwannomas in the penis and pelvis. A 32-year-old adult male presented with complaints of multiple small swellings on the penile shaft, which were associated with episodes of severe pain. Clinically, there were multiple small, firm to hard, tender nodular swellings on the penile shaft. Ultrasound and Magnetic Resonance Imaging (MRI) revealed six well-marginated lesions in the penile areolar tissue and two lesions along the course of the left sciatic nerve in the left hemipelvis. Surgical excision followed by histopathological evaluation confirmed the diagnosis of multiple schwannomas. Due to their rarity and non specific presentation, most of these lesions are not diagnosed clinically. Therefore, presurgical imaging is necessary to evaluate their anatomical and morphological features. Although imaging findings in schwannomas are not always precise, Histopathological Examination is required for a definitive diagnosis. Histopathology typically shows the mixed presence of Antoni A and Antoni B bodies containing spindle cells arranged tightly and loosely, respectively, in a collagenous matrix. Immunohistochemistry (IHC) typically shows positivity for S-100 protein, which is characteristic of schwannomas. They are also positive for neuron-specific enolase and vimentin, but negative for Cluster of Differentiation(CD) 117 and Smooth Muscle Actin (SMA). Schwannomas are treated by complete surgical excision with preservation of the nerve axon, and they have a good prognosis with a low chance of recurrence.