2008 Summer Meeting - Leeds - The Pathological Society of Great ...

P87Incompletely Differentiated (Unclassified) Sex Cord / GonadalStromal Tumour of the Testis with "Pure" Spindle CellComponent: A Case ReportSSen 1 , J Patel 1 , P Chaudhri 11 Lincoln County HospitalThe group of incompletely differentiated (unclassified) sex cord/gonadalstromal tumours includes rare cases with predominant spindle cell morphology.We report a rare case of a "pure" spindle cell tumour of the testis withmorphological and immunohistochemical features consistent with the diagnosisof "incompletely differentiated sex cord / gonadal stromal tumour".A 39-year old male presented with a lumpy/hard left testis, clinicallysuspected as a tumour on ultrasound. A left radical orchidectomy wasperformed. We received a testis with attached spermatic cord containing a 5mm nodule at the periphery. Microscopically, the nodule was predominantlycomposed of benign spindle cells arranged in fascicles with no evidence ofmitoses or necrosis. These were admixed with steroid cells with epitheloid andsignet ring morphology. Immunostaining for S100, inhibin and SMA waspositive, a pattern also seen in both adult and juvenile granulosa cell tumours;whereas desmin, CD34, c-kit and cytokeratin was negative. This concurrentpresence of some morphological and immunohistochemical features of bothsteroid and granulosa cell lines in the tumour suggests its origin from a stromalstem cell, possibly capable of dual differentiation, but with an arrest ofmaturation at an early phase of differentiation.Unclassified sex cord stromal tumours (SCSTs) of the testis can occur atall ages, but most common in children (30% in < 1 yr). The behavior is mostlybenign in prepubertal (