Abstract
Introduction/Objective The diagnosis of neuroendocrine carcinoma (NEC) in a lung explant represents a rare and diagnostically challenging scenario. NEC is an aggressive, high-grade malignancy characterized by distinct histopathologic and immunophenotypic features. Its occurrence in the context of solid organ transplantation raises important questions about tumor pathogenesis, immunosurveillance, and transplant related malignancy risk. Methods/Case Report A 74-year-old male with a history of bilateral lung transplant for fibrotic hypersensitivity pneumonitis presents with worsening shortness of breath. His transplant course was complicated by the incidental discovery of a 2.1 cm high-grade neuroendocrine carcinoma (NEC) in the explanted right lower lobe. Despite undergoing two cycles of carboplatin and etoposide (stopped due to pancytopenia), he has experienced disease progression with mediastinal involvement and the development of bilateral malignant pleural effusions. Ultimately succumbed to his disease. Results NA Conclusion Lung transplantation remains the only definitive treatment for end-stage lung disease, with a 5-year overall survival of approximately 59% and significant quality of life improvements. Despite rigorous preoperative screening, incidental malignancies in explanted lungs are reported in 0.5–2.4% of cases, dramatically impacting long-term outcomes. In our patient, the incidental high-grade NEC, a very rare entity in lung explants, underscores the diagnostic and therapeutic dilemma of balancing immunosuppression with oncologic management. The presence of these occult tumors necessitates more aggressive surveillance strategy, influences immunosuppressive management, and complicates therapeutic decisions. Advanced imaging and comprehensive pathological evaluation of explanted lungs are critical, although their routine application remains limited by cost and practicality.