Bullous pilomatricoma: A stage in transition to secondary anetoderma?

Abstract

Pilomatricoma is an uncommon hamartomatous tumor of the hair matrix. Bullous and anetodermic changes over pilomatricoma are rare. We report an 18-year-old male with an asymptomatic nodule with overlying cystic changes on the left arm of 6-month duration with clinical and histological features of both bullous and anetodermic modifications. We also reviewed the associated literature to conclude that there is sufficient overlap in these two entities. Both variants show a bullous or pseudobullous appearance clinically and loss of elastin, sparse collagen bundles separated by intense edema, and dilated lymphatics/blood vessels in the dermis overlying the tumor mass histologically. We therefore propose that bullous, pseudoampullary, anetodermic, and lymphangiectatic forms should be considered as synonymous or transitional to the ultimate scar-like anetodermic appearance.

Bullous pilomatricoma: A rare variant resembling bouncy ball

“…[91011] Bullous pilomatricoma has a predilection for occurring on the shoulder and upper arm regions, predominantly in females. It can also be found on the neck, trunk, eyelid, and scalp.…”

A Compressible Bulla on the Upper Back of a Teen

“…Uncommonly, a pilomatricoma may present with an overlying semitransparent, wrinkled, thick‐walled bulla. The overlying bulla appears tense but collapses to a flaccid sack with applied pressure . This clinical variant has been termed bullous pilomatricoma.…”

“…Other described variants of pilomatricomas include giant, pigmented, multiple, familial, pseudoampullary, lymphangiectatic, and anetodermic pilomatricomas . It has been proposed that bullous pilomatricomas may exist on the same clinical spectrum with lymphangiectatic, pseudoampullary, and anetodermic pilomatricomas, which have been reported with overlapping clinical and histopathologic features . It is plausible that hydrostatic pressure from dermal edema or possibly damage mediated by elastolytic enzymes released near a bullous pilomatricoma may disrupt collagen and elastin over time and ultimately result in overlying anetoderma.…”

Bulla-like Malherbe’s Calcyfying Epithelioma Induced by Deltoid Muscle Rupture

“…Different clinical manifestations of bullous pilomatricomas have been described as erythematous, bluish or skin-colored, semi-transparent, heavily folded or striae-like, flaccid blisters, overlying a solitary, firm nodule [4]. The skin overlying pilomatricoma can sometimes be atrophic.…”