Fine needle aspiration cytologic findings in four cases of pilomatrixoma (calcifying epithelioma of Malherbe).

Four cases of pilomatrixoma studied by fine needle aspiration (FNA) biopsy prior to resection and histologic diagnosis were reviewed to identify the cytologic features useful in making the FNA cytodiagnosis. Cytopathology had initially correctly diagnosed two cases while misdiagnosing one as a carcinoma and one as a suspected carcinoma. The aspirates from all cases contained either clustered or isolated basaloid cells, with variably sized nuclei and prominent nucleoli. "Ghost cells" were also present in most smears stained with the Giemsa stain and could thus be very helpful for making the FNA diagnosis of pilomatrixoma. The occurrence of either foreign-body giant cells or calcium deposits in the aspirates could also contribute to suggesting the correct diagnosis of pilomatrixoma in some cases.