Pulmonary Hamartoma Initially Misdiagnosed as Adenocarcinoma: A Case Report and Review of the Literature.

Pulmonary hamartomas are common benign lung tumours that rarely present with hemoptysis and may mimic malignancy. We report a 39-year-old non-smoker with 2 months of hemoptysis and a 3-cm right upper-lobe lesion. CT-guided core biopsy with IHC suggested adenocarcinoma (CK7, TTF-1, Napsin-A positive), but PET-CT showed no metastasis. The patient underwent VATS resection and final histopathology confirmed pulmonary hamartoma. Symptoms resolved postoperatively with no recurrence at 6-month follow-up. This case highlights potential false-positive biopsy/IHC results from entrapped benign epithelium and the role of surgical excision for definitive diagnosis.