Pilomatrixoma: Clinicopathologic study of 51 cases with emphasis on cytologic features

Abstract

The clinical and pathologic features of 51 cases of pilomatrixoma found in our archives from 1990-1999 were reviewed, with emphasis on the cytopathologic features of the 22 cases that were sampled by fine-needle aspiration (FNA) biopsy prior to excision. Although uncommon, almost 20% of the pilomatrixomas in this series occurred in adults over age 30. Of the commonly reported features, the presence of basaloid cells and ghost cells in FNA smears, associated with a cutaneous location of the lesion, was sufficient for a confident cytologic diagnosis of pilomatrixoma. The presence of foreign body-type giant cells, nucleated squamous cells, and calcification, alone or in combination, was less specific, but supported a diagnosis of pilomatrixoma. Although infrequently reported, prominent nucleoli in basaloid cells and smears containing refractile keratin clumps were very useful clues in the diagnosis of pilomatrixoma. Finally, the routine use of cell blocks is recommended because in many of the cases presented ghost cells were fragmented or obscured in smears, but were more readily identified in cell block sections.

An 8-Year-Old Girl with Multiple Subcutaneous Nodules: Pilomatrixoma

“…Other key components that assist in the diagnosis are foreign body giant cells and nucleated squamous cells. Calcium deposits are less definitive according to Wang et al [10] as they were present in only 55% of the cases in their study. In our patient, histopathologic findings were all typical for pilomatrixoma.…”

Pilomatricoma of the Retroauricular Area

“…Computed tomography or magnetic resonance imaging are mainly requested for certain cases such as preauricular and extensive tumors (5,12). As a part of diagnostic investigation fine needle aspiration has been described (18).…”

“…The tumor contains basaloid cells with nucleus settled in the peripheral of the island and eozinofilic shadow cells (ghost cells) without nucleus settled in the center (5,6,12). Calsification in the ghost cell region is common feature that ranges from 69% to 85% (18). Malign forms have atypical, undifferentiated cells, a large epithelial cell component and may infiltrate blood vessels and fibrous capsule (12,20).…”

An Interesting Cytology and Histopathological Correlation of Adnexal Tumor

“…Aspirates from older lesions may even show only ghost cells. 3,4 Lesions that mimic Pilomatrixoma are skin appendageal tumors are trichilemmal cyst , epidermal inclusion cyst , cylindroma, malignant neoplasms (squamous and basal cell carcinoma) and granulomatous lesions. 5,6 Skin appendage tumors, such as cylindroma, eccrine spiradenoma and hidradenoma, contain mainly basaloid cells .…”