engleski

Pilomatrixoma in adults: a challenge for cytologists

OBJECTIVE: Although pilomatrixoma is a benign skin adnexal tumour arising usually in the head and neck region in children, it could be detected by fine-needle aspiration cytology (FNAC) in other body sites and in adults as well. We wanted to warn cytologists to think of this tumour while performing FNAC on skin nodules as well as to delineate diagnostic cytological features that can be helpful in making the distinction from various primary cutaneous malignant tumours. MATERIAL AND METHODS: Within five years (2001-2006) cytologists have performed FNAC of pilomatrixoma in 16 patients with or without ultrasound guidance using 23 or 25G needles attached to 10-ml or 20-ml disposable syringes. Smears were stained with Papanicolaou and Pappenheim staining. The preoperative cytological diagnoses were compared with the final histopathological ones. RESULTS: A total of 16 FNAC of pilomatrixomas were performed out of which 12 were diagnosed in adults (26 to 87 years old) mostly males. Accurate cytological diagnoses were made in 14 patients. Two cases were misdiagnosed (both in adults): in one case basal cell carcinoma could not be excluded, and another one was misdiagnosed for squamous carcinoma. Diagnostic cytological features for pilomatrixoma include cellular aspirates, keratinized squamous and ghost cells, multinucleated giant cells, pink and fibrillary material enveloping clusters of small, basaloid epithelial cells with a high nuclear-cytoplasmic ratio and prominent nucleoli. CONCLUSION: The fine-needle aspiration cytological diagnosis of pilomatrixoma may be extremely difficult especially if there is a predominance of one component over the others. It should be considered in the differential diagnosis of small cell and keratinizing lesions of skin at any age with different clinical presentation. It is important that cytologist performs aspiration because of adequate sampling and clinical data that could be helpful in combination with morphological features for making an accurate cytological diagnosis.

pilomatrixoma; FNAC

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