Pulmonary Enteric Adenocarcinoma in a Super-Elderly Patient: A Case Report and Literature Review.

Pulmonary enteric adenocarcinoma (PEAC) is an extremely rare subtype of non-small cell lung cancer, characterised by histopathological features that resemble colorectal adenocarcinoma. Here, we report a case of PEAC in an 85-year-old male who presented with a pulmonary nodule initially identified at the age of 76. Initial PET-CT (maximum standardised uptake value [SUVmax] = 2.8) was inconclusive, leading to strict follow-up. Over 9 years, the nodule enlarged significantly (3.2 cm, SUVmax = 8.4). A transbronchial biopsy confirmed adenocarcinoma, and the patient underwent successfully video-assisted thoracoscopic surgery with lymph node dissection. The histopathological analysis revealed CK7 and CK20 positivity, focal CDX2 positivity, and TTF-1 negativity, confirming PEAC. Despite advanced age, the patient tolerated surgery well without adjuvant therapy. At the one-year postoperative follow-up, he remained disease-free. This case emphasises the diagnostic utility of immunohistochemistry and the feasibility of surgical management, even in super-elderly patients with PEAC.