HCG-secreting malignancies – diagnostic pitfalls

Abstract

We present a case of a 34-year-old male patient referred to our Uro-oncology Department with a suspicion of a metastatic germ cell tumour, owing to enlarged left testicle and elevated b-hCG concentration (39 mIU/mL). Impaired performance status caused by extensive pulmonary and liver metastases, accompanied by significant lymphadenopathy, necessitated prompt management. However, a testicular tumour was excluded on ultrasound imaging; a hydrocele only was found. The b-hCG concentration was not increasing (37 mIU/mL). We found a diagnosis of an extragonadal germ cell tumour doubtful, and a liver biopsy was performed. Due to the patient’s quick deterioration, we decided to commence pre-phase chemotherapy with cisplatin and etoposide, which resulted in a significant clinical improvement. The pathological examination, along with immunoassays, revealed undifferentiated cholangiocarcinoma, and the patient continued chemotherapy with a biliary tract cancer regimen, i.e. cisplatin and gemcitabine. Unfortunately, the clinical response was short-lived; the disease progressed, the patient was offered best supportive care and died two months after the diagnosis. The case underpins the literature review with respect to differential diagnosis of an elevated hCG concentration. In particular, we discuss ectopic secretion in non-trophoblastic and non-germinal malignancies and the causes of false positive assays.