Transformation of lung adenocarcinoma to small cell lung carcinoma in the setting of tyrosine kinase inhibitor therapy: Cytological approach of a clinically challenging phenomenon.

Lung adenocarcinoma transformation into small cell lung carcinoma is a well-established phenomenon. Several reports and studies have been published, describing the clinical and pathological clues to detect this transformation. This article will discuss the cytological aspect of this entity, highlighting pertinent features, to bring more attention to the existence of this transformation into the cytopathology practice.