Adenosquamous carcinoma of the lung diagnosed by cytology?: A diagnostic dilemma

Adenosquamous cell carcinomas of the lung are rare tumours and are associated with a poor prognosis compared to other non‐small cell carcinomas. We report a case of a solitary lung carcinoma evaluated by bronchial brush and lavage cytology, bronchial biopsy and pleural fluid cytology. Cytological assessment of the pleural fluid demonstrated non‐small cell carcinoma and immunohistochemical staining confirmed a metastatic lung adenocarcinoma. The bronchial brush and lavage specimens, however, demonstrated the cytomorphological features of squamous cell carcinoma, which was confirmed by the bronchial biopsy. The finding of a mixed squamous and glandular component predicts a poor prognosis for this patient. The identification of a squamous component with the non‐small cell carcinoma is important as this excludes the patient from anti‐VEGF monoclonal antibody treatment due to the increased risk of haemorrhage. Diagn. Cytopathol. 2012. © 2011 Wiley Periodicals, Inc.