Akinsanya, AdeyinkaSegura, SheilaCramer, HarveyMesa, Hector2025-01-222025-01-222025Akinsanya A, Segura S, Cramer H, Mesa H. Adenosquamous carcinoma arising within a long-standing intrapulmonary bronchogenic cyst in an adult presenting with hyponatraemia. Cytopathology. 2025;36(1):75-78. doi:10.1111/cyt.13446https://hdl.handle.net/1805/45369A 74-year-old woman's persistent hyponatraemia led to the discovery of an adenosquamous carcinoma within an intrapulmonary bronchogenic cyst (IPBC), diagnosed 59 years prior. This is the first reported case of such a transformation in an IPBC. An adenosquamous carcinoma, originating from an intrapulmonary bronchogenic cyst identified 59 years prior, was discovered during the workup for a patient's unexplained, persistent hyponatraemia.en-USAttribution 4.0 InternationalAdenosquamous carcinomaBronchogenic cystHyponatremiaNeoplastic cell transformationNon‐small cell lung carcinomasArticle