Fine-needle aspiration cytology of pilomatrixoma: A short series of three cases

Abstract

Pilomatrixoma (PMX) (pilomatricoma, calcifying epithelioma of Malherbe) is a benign tumor with differentiation toward the hair matrix cells and is common in head and neck region. It is most commonly seen in the first two decades of life and presents as a subcutaneous, small, asymptomatic firm solitary nodule. Fine-needle aspiration cytology (FNAC) has been described as an important preoperative diagnostic investigation though on cytology the diagnosis of PMX is sometimes difficult and misdiagnosed. We describe two patients with gradually increasing asymptomatic swelling on pinna and middle finger. FNAC was done and a diagnosis of PMX was given, further confirmed by histopathological examination. The present cases highlight the importance of FNAC in considering PMX as differential diagnosis of dermal or subcutaneous nodules in locations other than head and neck. Cytopathologists who play an important role in the preliminary diagnosis should keep in mind the variability of the cellular composition of these types of lesions to avoid misdiagnosis.

A retrospective comparison of salivary gland fine needle aspiration reporting with the Milan system for reporting salivary gland cytology

“…This specimen was sent to us as a parotid FNA. This benign skin adnexal tumour is well‐recognised as a cytological pitfall for the over diagnosis of malignancy, with degenerate squamous and basaloid cells, nuclear pleomorphism and occasional large nucleoli Figure .…”

Cyto-histopathological correlation of skin adnexal tumors: A short series

“…[ 23 ] Variability of cellular composition of these lesions should always be considered to avoid any misdiagnosis. [ 24 ] Apocrine lesions of the skin are rare and are found mainly in body folds including the axillary, groin, and anogenital regions, where apocrine glands are most commonly encountered. In lesions of apocrine origin, the cells have abundant eosinophilic cytoplasm and eccentric, basally located nuclei.…”

A subcutaneous firm nodule on scrotal skin: Cytological considerations

“…[ 5 ] FNAC of pilomatrixoma may show the presence of anucleated squames and basaloid cells, which were absent in the present case. [ 5 ] A possibility of necrotic debris was ruled due to the lack of inflammatory background.…”

“…[ 1 ] Pilomatrixoma is cytologically characterized by the presence of basaloid cells, calcium deposits, naked nuclei, shadow (“ghost”) cells, giant cells, and inflammatory background. [ 5 ] Steatocystoma shows acellular, granular debris, rare cholesterol crystals, and anucleate squames. [ 9 ] Ancient schwannoma, which shows secondary changes including calcification, is usually hypocellular consisting of clusters of spindle cells with elongated nuclei.…”

“…[ 1 - 4 ] This material may be surrounded by lymphocytes and foreign body giant cells. [ 4 , 5 ] The epithelial cells are usually absent in the cytological smears of scrotal calcinosis. [ 1 - 4 ]…”