Fine-needle aspiration features of pilomatrixoma

University of Gothenburg, Goeteborg, Västra Götaland, Sweden
Cancer (Impact Factor: 4.89). 08/2001; 93(4):252-6. DOI: 10.1002/cncr.9038
Source: PubMed


Pilomatrixoma (PMX) is a benign skin neoplasm of hair matrix origin. The fine-needle aspiration (FNA) features of PMX frequently lead to a misdiagnosis of carcinoma.
Nine cases of PMX in which a preoperative FNA was performed were reviewed. The cytologic features were compared with the histologic appearance of corresponding surgical specimens as well as with cytologic features of tumors that arose in the differential diagnosis.
Unequivocal benign diagnoses were rendered in three cases; the correct preoperative diagnosis of PMX was rendered in two of these cases and considered in an additional case. In four additional cases, carcinoma was diagnosed or could not be excluded. A noncommittal diagnosis of epithelial tumor, most likely of skin adnexal origin, was rendered in an additional single case. Retrospective review of the FNA smears in all nine instances disclosed cytologic features that corresponded well with the histologic components of PMX. Diagnostic cytologic features included cellular aspirates; clusters of small, primitive-appearing basaloid epithelial cells; a high nuclear-cytoplasmic ratio; evenly dispersed chromatin; prominent nucleoli; pink, fibrillary material enveloping clusters of basaloid cells; multinucleated giant cells; and sheets of ghost cells.
The FNA cytologic diagnosis of PMX may be extremely difficult; its distinction from various primary cutaneous carcinomas is most problematic. Recognition of a unique constellation of cytologic features in FNA smears in the appropriate clinical context is most helpful in making this distinction.

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    ABSTRACT: Microcystic adnexal carcinoma (MAC) is an uncommon skin neoplasm with a predilection location around the lips. It is characterized by cords and nests of neoplastic cells forming ductular or glandular structures that are embedded in dense collagenous stroma. An eighty-seven year old Caucasian female patient presented with a painless, slowly enlarging mass measuring 3.3 × 2.7 × 1.0 cm on the lower lip for approximately 6 months. The patient underwent 2 fine needle aspiration biopsies (FNAs). Smears made from both FNAs demonstrated similar features including low cellular smears, three dimensional cell clusters forming a glandular structure, round to oval cells with high N:C ratio, occasional cytoplasmic lumens, without distinct hyperchromasia, focal inconspicuous nucleoli, smooth regular nuclear membranes, abundant naked nuclei, occasional squamoid cells and focal acellular stromal fragments in the background. The cytologic differential diagnosis included skin adnexal carcinoma and low grade mucoepidermoid carcinoma arising in the minor salivary gland. The mass was subsequently excised. The diagnosis of microcystic adnexal carcinoma was made. We report cytologic features of MAC and also suggest that MAC can possibly be diagnosed by FNA with the appropriate clinical vignette and immunohistochemical profile..
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