Dermoscopy of pilomatrixoma

Abstract

We saw two patients with painless swelling in head and neck area. First patient, a 34-year-old lady, presented with insidious onset, gradually progressive swelling over left cheek of 1 year duration. Examination showed solitary, 1.5 × 1 cm, non-tender, erythematous nodule over left cheek [Figure 1a]. Dermoscopy showed erythema, linear and dotted vessels, white homogenous area, white streaks and bluish area [Figure 1b]. Second patient, a 42-year-old lady with swelling of right pinna of 2 years duration [Figure 1c]. Dermoscopy showed erythema, linear irregular vessels, hairpin vessels, homogenous white area, white streaks and bluish areas [Figure 1d]. Histopathology showed well circumscribed nodule consisting of island of basaloid cells, shadow cells, multinucleated giant cells and area of calcification [Figure 2]. In both the cases, based on clinical, dermoscopy and histopathological feature, a diagnosis of pilomatrixoma was made and lesion was excised.Figure 1: (a and c) Clinical image showing pilomatrixoma over left side of cheek and right ear lobe (b) Polarised dermoscopy of nodule in image (b) shows erythema, linear irregular vessels (blue star), dotted vessels (yellow star), homogenous white area (blue arrow), white streaks (blue triangle) and bluish area (yellow arrow) (Dermlite DL4, ×10) (d) Polarised dermoscopy of nodule in image shows linear irregular vessels (blue star), homogenous white area (blue arrow), white streaks (blue triangle) and bluish area (yellow arrow). Yellowish scale can also be seen. (Dermlite DL4, ×10)Figure 2: Histopathology shows basaloid collection of cells (orange star) and ghost cells (yellow triangle) (H and E, 100×)Pilomatrixoma also known as calcified epithelioma of Malherbe is an adnexal tumour derived from immature matrix cells. It is more common in females, presents as solitary, erythematous to bluish, solid, nodular lesion over head and neck region or upper limbs. It can be multiple in Gardner’s syndrome or myotonic muscular dystrophy. It has varied morphology and is difficult to diagnose pre-operatively. In a study involving 346 cases, the pre-operative diagnosis was considered in 100 (28.9%) cases only.[1] Dermoscopy may help in diagnosis and shows bluish area that represent basaloid proliferation, white area representing calcification, white streaks represent fibrosis on histopathology. Vascular features like linear irregular vessels and hairpin vessels result from pressure due to tumour mass and angiogenesis. It also helps in differentiating from other diseases like nodular basal cell carcinoma, which shows arborising vessels, epidermoid cyst showing ivory white background colour and central punctum (pore sign).[2] Declaration of patient consent 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. Financial support and sponsorship Nil. Conflicts of interest There are no conflicts of interest.

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