Fine-needle aspiration cytology of basaloid squamous cell carcinoma and small cell carcinoma-a comparison study.

The cytopathologic diagnosis of basaloid squamous cell carcinoma can be problematic as there are several components of the differential diagnosis that share common cytomorphologic features. In this study, we report the fine-needle aspiration (FNA) findings of 16 basaloid squamous cell carcinoma cases and compare those cases to 16 cases of small cell carcinoma. To our knowledge, this is the largest series of basaloid squamous cell carcinoma FNA cases ever reported. The following cytomorphologic features were compared for both tumors: cohesive tissue fragments, single cells, adenoid cystic-like features (cribriform pseudoglandular lumina with hyaline materials), necrosis, nuclear size, nuclear molding, nucleoli, cytoplasm, and the presence of single keratinized cells. Adenoid cystic-like features and the presence of single keratinized cells were specific for basaloid squamous cell carcinoma (P < 0.05).