Leydig Cell Tumor Presenting as Peripheral Precocious Puberty in a Six-Year-Old Boy: A Case Report and Literature Review

Abstract

Background: Leydig cell tumour is an uncommon cause of gonadotropin-independent precocious puberty in prepubertal boys. Case Presentation: A 6-year-3-month-old boy presented with a three-month history of progressive penile enlargement and pubic hair development, without axillary hair or gynaecomastia. His stretched penile length was 6 cm. Serum testosterone was markedly elevated at 530 ng/dL, while basal luteinising hormone and follicle-stimulating hormone were both 0.30 mIU/mL. A gonadotropin-releasing hormone stimulation test showed a blunted response, with peak luteinising hormone of 1.55 mIU/mL at one hour, supporting a peripheral source of androgen excess. Bone age was advanced to 12 years. Scrotal Doppler ultrasonography demonstrated a 12.9 × 9.3 × 11.0 mm hypervascular lesion in the right testis, while the contralateral testis and abdominal organs were normal. The patient underwent right radical inguinal orchiectomy with high ligation of the spermatic cord using Chevassu's Manoeuvre. Histopathological examination confirmed a Leydig cell tumour, with no mitosis or necrosis and a clear spermatic cord margin. Post-operative serum testosterone decreased to 83.90 ng/dL at follow-up, accompanied by complete clinical resolution of the pubertal features. Conclusion: This case highlights the value of coordinated biochemical, stimulation-test, imaging, and histopathological assessment in identifying Leydig cell tumour-associated peripheral precocious puberty and the importance of continued post-operative endocrine surveillance.