# Schwannoma of Kidney: A Case Report of a Benign Entity With Rare Presentation

## TL;DR

A rare case of a benign kidney tumor called schwannoma is reported, highlighting the importance of histopathology for accurate diagnosis.

## Contribution

This case report adds to the limited literature on schwannomas in the kidney and emphasizes diagnostic challenges.

## Key findings

- A 55-year-old patient had a complex solid cystic mass in the kidney diagnosed as schwannoma.
- Histopathology and immunohistochemistry confirmed schwannoma with S100 and SOX10 positivity.
- Clinical and imaging findings were non-specific, mimicking common renal neoplasms.

## Abstract

Schwannomas are rare peripheral nerve sheath tumours involving the head, neck and extremities. Heart, lung, orbit and kidney are some of the rare sites for schwannoma involvement. Here, we present a 55-year-old patient with no specific complaints, who was detected to have a complex solid cystic mass in the lower pole of the left kidney. In contrast-enhanced computed tomography, the lesion was highly suggestive of malignancy. The patient underwent a laparoscopic radical nephrectomy. Grossly, the tumour was well-circumscribed and delineated from surrounding renal parenchyma. Microscopic examination revealed variably cellular spindle cell neoplasm arranged in palisades with intervening myxoid and cystic change. On immunohistochemistry, S100 and SOX10 were diffusely positive, consistent with schwannoma. We report this case for its rarity and to emphasize the fact that clinical and imaging findings are non-specific for this entity as it mimics the common renal neoplasms. Histopathology with supportive immunohistochemistry clinches the diagnosis.