ESPE Abstracts

Background: β-hCG secreting germ-cell tumors (β-hCG-ST) are rare causes of Peripheral precocious puberty (PPP) in boys and usually located in intracranial region. Liver, retroperitoneum, testis and mediastinal cavity are the other localizations reflecting embryonic germ cell sites.

Objective and hypotheses: We present a patient with PPP due to elevated β-hCG levels, but extensive efforts to find the source of elevated β-hCG was unrevealing for 6 years. We want to emphasize the difficulties at diagnosis of β-hCG-ST.

Case: 10.7 years-old male presented with pubic and body hair for 2.5 years. On physical examination; height was 172 cm (+5 SDS), weight was 60.5 kg (+2.28 SDS), testes were 10 cc bilaterally with genital/pubic hair of Tanner stage 5. Bone age was 16 years. FSH and LH was supressed with extremely elevated total testosterone (17 ng/ml). An elevated β-hCG level of 104 mIU/ml (Normal: 0–5) prompted a search for the source. Cranial MRI showed 7 mm contrast enhanced hypophyseal lesion which was taken out by trans-sphenoidal surgery. However, β-hCG remained elevated and the pathology came-back as normal pituitary tissue. Subsequently, an inferior petrosal sinus sampling was performed which also did not show any gradient or lateralization. Follow-up cranial/thoracal/abdominal/pelvic MRIs were normal. A testis ultrasound showed generalized microlithiasis but a biopsy to rule out tumour revealed only mild hyperplasia of Leydig cells. Testicular arterial and venous catheterization also did not show any β-hCG gradient. PET/CT revealed a small uptake in mediastinum and excisional biopsy of the lesion was done which showed thymus hyperplasia. Annual MRIs did not show any tumors for the next 6 years in which time β-hCG levels ranged 100–154 mIU/ml. At 6th years, his β-hCG abruptly increased to 2039 mIU/ml at which time MRI showed a 5.5 cm mediastinal mass. Tumor is excised completely and pathology was consistent with mixed germ cell tumor (70% mature teratom, 30% seminoma). Karyotype of tumor was 47,XXY (15)/48,XXY, +MAR (12). Peripheral karyotype was 46,XY.

Conclusion: β-hCG ST can not be evident at presentation and close follow up is mandatory in patients with PPP and elevated β-hCG.