Primary colloid adenocarcinoma of lung: A case report and review of literature

Colloid adenocarcinoma of the lung is a rare subtype of invasive adenocarcinoma, marked by abundant extracellular mucin and scattered neoplastic cells. We present a case of a 54-year-old chronic smoker with occupational stone dust exposure, who reported progressive dyspnea, dry cough, weight loss, and chest pain. Imaging revealed a lobulated left lower lobe mass with mediastinal lymphadenopathy, vertebral lesions, and a hepatic nodule suggestive of metastasis. Bronchoscopy showed airway narrowing, and transbronchial biopsy demonstrated mucin-filled alveolar spaces with neoplastic and signet ring cells. Histopathology confirmed colloid adenocarcinoma, with CK7 positivity, CK20 focal positivity, and TTF-1 negativity on immunohistochemistry. Fine needle aspiration of a supraclavicular node confirmed metastasis. This case highlights the importance of recognizing this uncommon tumor to guide diagnosis and management.