Cellular Testicular Fibroma of Gonadal Stroma with Extensive Myoid Differentiation: A Mimicker of Testicular Leiomyoma

摘要

Fibroma of the testis is a rare benign Sex Cord Stromal Tumour (SCST) of probable gonadal stromal origin, occurring in adult males.Characterised by slow and insidious growth, it is devoid of hormonal association and serum markers.Clinically, it can mimic seminoma and requires histopathological examination for identification.Microscopic characteristics include hypercellular spindle cell areas and hypocellular hyaline plaques.Authors report a case of a 41-year-old male presenting with complaints of lower abdominal pain and dysuria.Ultrasonography (USG) showed enlarged left testis with heterogenous echotexture.With a clinical diagnosis of testicular tumour, orchidectomy was performed.Histology showed a well circumscribed, encapsulated cellular neoplasm comprising of spindle and fusiform cells in fascicles, nodules and bundles.The cells showed fusiform vesicular nuclei and eosinophilic cytoplasm, focal epithelioid cells with grooved nuclei and occasional mitotic figure.Stromal collagen fibres and hyalinisation were noted.Testicular tissue was seen compressed peripherally.The tumour cells demonstrated positive reactivity for Smooth Muscle Actin (SMA), h-Caldesmon and inhibin, negative for S-100 and CD34 (Cluster of Differentiation) on Immunohistochemistry (IHC).Literature review helped in arriving at a diagnosis of cellular Testicular Fibroma (TF) with myoid differentiation.Testicular spindle cell lesions are rare, and comprise of different entities, one of which is TF.Histology and IHC are useful aids in diagnosis.Awareness of the differential diagnosis and the IHC markers can help in arriving at a conclusive diagnosis.