Fine-needle aspiration cytology of metastatic basal cell carcinoma of the skin to the lung.

Metastatic basal cell carcinomas of the skin are rare. We present the cytologic features of a metastatic basal cell carcinoma to the lung diagnosed by fine-needle aspiration biopsy. Cytologic examination revealed syncytial groups of relatively small cells with hyperchromatic, oval to spindle-shaped nuclei having high nuclear to cytoplasmic ratios. Immunocytochemical studies performed on the cell block sections revealed the malignant cells to be positive for cytokeratin (AE1/3) and negative for neuroendocrine markers, [neuron specific enolase (NSE) and chromogranin (Phe-5)]. We reviewed the literature related to metastatic basal cell carcinoma of the skin and discuss risk factors and mechanisms of metastatic spread. In addition, a discussion of the other entities that can enter into the differential diagnosis is presented along with the role of ancillary studies. To the best of our knowledge, we believe this is the first case report of the fine-needle aspiration (FNA) cytology of a basal cell carcinoma metastatic to the lung.