Beta-human Chorionic Gonadotropin-secreting Lung Adenocarcinoma

Overexpression of beta-human chorionic gonadotropin (β-hCG) is frequently associated with germ cell tumours, especially choriocarcinoma. Ectopic secretion of β-hCG by non-small cell lung cancer is exceptional. We present an exceedingly rare case of pulmonary adenocarcinoma that secretes β-hCG. Our patient is a 62-year-old postmenopausal woman, a nonsmoker, who presented with a six-month history of progressive dyspnoea, associated with decreased appetite and significant weight loss. Her serum β-hCG was very high (11211.9 mIU/ml), which prompted investigations to exclude germ cell tumour. Radiological imaging revealed a 10-cm right lung mass with adrenal metastasis. No other focal lesions were detected. Microscopy of the lung biopsy specimen showed replacement of normal lung tissue by sheets of malignant cells, forming vague glands in some areas. Immunohistochemically, the malignant cells showed focal immunopositivity for thyroid transcription factor 1 (TTF-1), napsin A, cytokeratin 7 (CK7) and β-hCG. A diagnosis of β-hCG-secreting pulmonary poorly differentiated adenocarcinoma was rendered. Serum β-hCG level decreased significantly to 168.6 mIU/ml after the first cycle of chemotherapy. In conclusion, β-hCG expression in lung cancer should be recognised to facilitate prompt diagnosis and initiation of appropriate intervention.

Keywords
HCG-beta; carcinoma; non-small cell lung; adenocarcinoma; germ cell tumour