Pilomatrixoma: A Masquerader at Uncommon Sites.

The rarity, diverse clinical presentation, relatively featureless sonography, and diagnostic dilemma associated with pilomatrixomas may trigger anxiety and call for unwarranted investigations. The authors have shared their experience in two consecutive cases to generate awareness for such lesions. Copyright:

Case-1: A 12-year-girl with a painless, bony-hard swelling on medial aspect of left leg [Figure 1]. Radiography: No calcification; Sonography: No vascularity. Serology: Echinococcus-negative. Case-2: A 6-year-boy with a similar 4.2 cm × 3.8 cm mass in left flank. Histopathology was consistent with pilomatrixoma in either case [Figure 2]. Postexcision, patients are asymptomatic upon follow-up (4.5 and 2 years, respectively).

Figure 1

Pilomatrixoma. Clinical picture of the solitary lesion on medial aspect of left leg; with excised specimen (inset)

Figure 2

The triad of ghost cells, basaloid cells with high nuclear: cytoplasmic ratio and chromatin/foreign body giant cells inside the nuclei are suggestive of Pilomatrixoma. Case 1 (a) The tumor shows nests of basaloid cells (black arrow) with abrupt trichilemmal type of keratinization and presence of ghost cells (blue arrow) ×200, H and E (left). Foci of calcification (black arrow) seen ×100, H and E (middle). Foreign body giant cell reaction (blue arrow) ×100, H and E (right). Case 2 (b) The tumor is composed of islands of basaloid cells which show abrupt trichilemmal type of keratinization and ghost cells in the center of the islands, ×100 (left and middle), ×200 (right) H and E

Pilomatrixoma or “calcifying epithelioma of Malherbe” is a rare, benign, hair-follicle tumor[1] with a bimodal-peak presentation (first-and-sixth decades-of-life) and female-preponderance. The head-neck regions (>50% of cases) followed by upper extremities are commonly affected. Excision biopsy with clear margins is curative with recurrence reported in 0%–3%.[2]

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The authors certify that they have obtained all appropriate patient consent forms. In the form, the patient(s) has/have given his/her/their consent for his/her/their images and other clinical information to be reported in the journal. The patients understand that their names and initials will not be published and due efforts will be made to conceal their identity, but anonymity cannot be guaranteed.

Conflicts of interest

There are no conflicts of interest.