Unclassified sex cord / gonadal stromal testis tumour with a pure spindle cell component

Abstract

Incompletely differentiated sex cord / gonadal stromal tumours of the testis (SCST) of pure spindle cell morphology are extremely rare with only four reported cases in the literature.1 We report a case of a 73-year-old man who presented with acute on chronic renal failure and noted to have an enlarged tender left testicle. Ultrasound examination revealed an enlarged testis (40 cc) with diffuse heterogeneity of the testicular parenchyma. A radical orchiectomy procedure was performed. The histological examination revealed a well circumscribed tumour (55 mm in maximum diameter) comprised purely of fascicles of spindle cells with elongated to ovoid nuclei. Immunohistochemical stains demonstrated positive staining for Vimentin, S100, SMA, Inhibin, Calretinin and CD99. EMA, Cam 5.2, AE1&3, Desmin, CD34, Melan-A, HMB-45, Sox10, CD117 and PLAP stains were negative. The overall features were consistent with the diagnosis of unclassified SCSTs of pure spindle cells morphology. Due to the rarity, SCST of spindle cell morphology are under studied. They are of unknown clinical behaviour. However, they should be considered in the differential diagnosis of spindle cell lesions of the testis.