Psoriatic plaques "koebnerizing" to areas of acanthosis nigricans in an obese female: clues to a common pathway?

Recent evidence suggests that the activation of several growth factor receptors (EGFR, IGFR1, and FGFRs) is a possible cause of acanthosis nigricans, a skin disorder characterized by velvety thin plaques in skin folds and often seen in patients with insulin resistance. The authors report a 14-year-old obese (body mass index = 38.5kg/m(2)) girl with a history of polycystic ovarian syndrome and pre-diabetes who presented with psoriatic plaques in her scalp and, subsequently, in areas mostly confined to where she had characteristic lesions of acanthosis nigricans. The authors propose that this as-of-yet unreported observation may represent a preferential koebnerization phenomenon where the abnormal keratinocyte proliferation in acanthosis nigricans may serve as the epidermal "micro-trauma" necessary to incite the prototypical isomorphic response seen in psoriasis.