Lymphangitic breast cancer in explanted lungs with interstitial lung disease: an unexpected finding.

A 60-year-old woman with end-stage fibrosing interstitial lung disease (ILD) underwent bilateral lung transplantation. Systematic histological analysis of the explanted lungs revealed extensive lymphangitic carcinomatosis and hilar lymph node metastases from a previously undiagnosed breast carcinoma. Retrospective imaging review identified a suspicious mammographic finding that had not been further investigated. The patient was later diagnosed with metastatic breast cancer and passed away at 12 months post-transplant. This case emphasizes the challenging diagnosis of neoplasia in end-stage lung disease. The incidence of malignancies in explanted lungs is approximately 1.65%, with metastatic cases being extremely rare. This report underscores the importance of thorough histopathological evaluation of explant lungs, advocating for standardized examination protocols to improve the accuracy and depth of pathological diagnosis.