MIXED EPITHELIAL AND STROMAL TUMOUR OF THE KIDNEY - A RECENTLY RECOGNISED RARE ENTITY

Mixed epithelial and stromal tumour (MEST) a predominantly benign tumour of the kidney has recently been described and accounts for 0.2-0.28 percent of all renal tumours. Here we report a case of MEST in a 45 year old postmenopausal woman. She presented with abdominal pain and dysuria. Radiological studies revealed a renal mass which was suspected to be malignant. The resected kidney showed a solid and cystic mass arising from the lower pole of the kidney. Histologically the tumour showed biphasic pattern with epithelial and stromal components and a diagnosis of MEST was made. Immunohistochemistry showed cytokeratin positivity in the epithelial component and vimentin positivity in the stromal component. There was no malignant focus. The prognosis of these tumours is usually very favourable. However, malignant cases have been described. Therefore, while dealing with cystic lesions of the kidney this rare entity and the even rarer possibility of malignant change should be borne in mind.