Hepatoid Carcinoma of the Lung: A Rare Presentation

Hepatoid adenocarcinoma of the lung (HAL) is a rare pulmonary malignancy that resembles hepatocellular carcinoma morphologically and poses diagnostic challenges, particularly when alpha‐fetoprotein (AFP) is absent. We report a man in his 50s with chronic obstructive pulmonary disease and a solitary 1.9‐cm right upper lobe nodule. Percutaneous biopsy identified non‐small cell carcinoma without establishing the subtype. Video‐assisted thoracoscopic right upper lobectomy with mediastinal lymphadenectomy revealed a hepatoid tumour expressing HepPar‐1 and CK7 but not AFP, arginase‐1 or glypican‐3. The absence of a hepatic lesion on staging imaging supported a pulmonary primary. The tumour was pT1bN0 with no clinically detected metastases. At 6 months after resection, there was no evidence of recurrence. This case illustrates the limitations of small biopsies and isolated immunohistochemical markers in diagnosing an AFP‐negative pulmonary hepatoid tumour.