A Testicular Masquerader: Sertoli Cell Tumour (Not Otherwise Specified) of the Testis Mimicking Seminoma in an Adult Male

Abstract

Background: Sertoli cell tumour (SCT) of the testis is a rare sex cord-stromal neoplasm, accounting for less than 1% of all testicular tumours. Because SCTs are usually clinically silent and radiologically indistinguishable from germ cell tumours, they are frequently misdiagnosed as seminoma preoperatively, and histopathological examination remains the definitive diagnostic standard.

Case Presentation: A 54-year-old male presented with a slowly progressive, painless left scrotal swelling of five years’ duration following a remote scrotal injury. Local examination revealed an 8 × 4 cm left testicular swelling with a positive transillumination test. Serum tumour markers (β-human chorionic gonadotropin and alpha-fetoprotein) were within normal limits; lactate dehydrogenase was mildly elevated. Scrotal ultrasonography showed a heterogeneous hypoechoic intratesticular lesion with increased vascularity and an associated hydrocele, suggestive of a testicular neoplasm. A clinical diagnosis of seminoma was made, and the patient underwent left radical inguinal orchidectomy with herniorrhaphy. Histopathological examination revealed a well-circumscribed, encapsulated grey-yellow tumour composed of cells with round, fine-chromatin nuclei arranged in nests and tubules separated by fibrous septa, with neither necrosis, lymphovascular invasion, nor significant nuclear atypia. A final diagnosis of Sertoli cell tumour, not otherwise specified, pT1b, was rendered.

Conclusion: This case underscores the importance of maintaining a high index of suspicion for Sertoli cell tumour among testicular masses that mimic seminoma and highlights histopathology, supplemented by immunohistochemistry when needed, as the diagnostic gold standard. Because SCT carries a small but definite risk of malignant behaviour, long-term clinical and radiological surveillance is warranted even when initial histology appears benign.

Keywords: Sertoli cell tumour; sex cord-stromal tumour; testicular neoplasm; seminoma; orchidectomy