Segmental Acne versus Mosaic Conditions with Acne Lesions

Abstract

Acne rarely presents in segmental patterns, which are encountered only in cutaneous mosaicism. We report herein two cases of segmentally arranged acne and systematically review the literature on the topic. Beside already known mosaic conditions which may show primary lesions typical of acne, i.e. nevus comedonicus, Happle-Tinschert syndrome, acne superimposed on epidermal nevi and mosaic Apert syndrome, we introduce the possibility that acne itself may present in a mosaic form. As from the extremely small casuistics retrieved, segmental acne is not present at birth, follows Blaschko lines, is polymorphous in nature and occurs on locations typical of common acne.

Blaschko line acne on pre-existent hypomelanosis reflecting a mosaicFGFR2mutation

“…Acne is also a feature of several genetic conditions, including monogenic disorders such as autoinflammatory syndromes or Apert syndrome. Several mosaic forms of acne have been described clinically . The underlying molecular mechanisms remain mostly hypothetical and have only been explored in a few cases of mosaic manifestation of Apert syndrome .…”

“…Several mosaic forms of acne have been described clinically. 2,3 The underlying molecular mechanisms remain mostly hypothetical and have only been explored in a few cases of mosaic manifestation of Apert syndrome. 4,5 Here we report a 12year-old boy who developed early, severe acne on pre-existent hypopigmentations distributed along Blaschko lines on the trunk, arms and face.…”

Extensive Nevus Comedonicus Involving the Palm: Questionable Role of the Pilosebaceous Unit in Pathogenesis

“…In view of the palmar involvement, we considered other rare conditions with similar morphology, such nevus trichilemmocysticus, Happle Tinschert syndrome (basaloid follicular hamartomas with comedo‐like plugs), segmental acne, and mosaic Apert's syndrome, as possible differential diagnoses . Characteristic histopathology discounted the first two possibilities in our patient and onset at birth ruled out the third.…”

“…Men and women are equally affected . A recent review discussed a few rare conditions with mosaic acneiform lesions, some of which may be related pathogenetically to tyrosine kinase receptor signalling pathways . We report a case of nevus comedonicus distributed over the left half of the body, including the palm, without any associated systemic abnormalities and briefly review the recent literature on mosaic conditions with acneiform lesions and their pathogenesis.…”

Acne arising on a facial Becker nevus following the lines of Blaschko

“…A review of 375 cases demonstrated that most patients (n = 349) were affected by nevus comedonicus, all following the lines of Blaschko. 2 In relation to the association with BN, only 10 cases were described, all in the thoracic region with a block-like configuration, none of them following the lines of Blaschko. 2 …”