FINE-NEEDLE ASPIRATION (FNA) CYTOLOGY OF PILOMATRIXOMA

FNA smears from five histologically confirmed cases of pilomatrixoma w ere reviewed to delineate the cytological features helpful in diagnosi s. A combination of basaloid cells, ghost cells and foreign body giant cells appeared to be necessary in FNA smear for a confident cytodiagn osis of pilomatrixoma. Presence of naked nuclei, nucleated squamous ce lls and calcification were additional features in favour of the diagno sis. Another 10 cases with initial cytodiagnosis of pilomatrixoma or b enign skin appendage tumour were reviewed. Using the above criteria, d iagnosis of pilomatrixoma was easy in five cases. One case was problem atical due to presence of atypical squamous cells. Initially the cytol ogical features were most commonly confused with epidermal inclusion c yst, giant cell lesion or a squamous cell carcinoma. The main reasons for erroneous diagnosis were lack of awareness of cytological features , predominance of one component over the others, and non-representativ e FNA smears. Atypia in nucleated squamous cells, and misinterpretatio n of basaloid cells as malignant can lead to diagnostic dilemma. Adequ ate clinical data are also necessary.