Acral persistent papular mucinosis.

Acral persistent papular mucinosis (APPM) is a subtype of localized lichen myxedematosus (LM) characterized by the chronic development of white to skin-colored papules and limited to the extensor surfaces of the hands and distal part of forearms, in the absence of systemic or laboratory manifestations. There is a strong predominance in women. Histopathology shows focal accumulation of mucin in the upper portion of the dermis sparing the grenz zone. The etiology is unknown. It is a benign condition, although dynamic changes occur with the progressive development of additional lesions. No specific treatment is required, and patients should be reassured about the prognosis.