Abstract
A 77-year-old female with a past medical history of hypertension and hyperlipidemia presented to the clinic for evaluation of asymptomatic papules on the bilateral dorsal hands and forearms that had been present for years. Histological analysis of a punch biopsy from the left forearm revealed extensive papular mucin deposition in the upper reticular and papillary dermis, separated by a Grenz zone from the overlying epidermis, and included the presence of scant stellate fibroblasts. The findings were indicative of acral persistent papular mucinosis (APPM), which were further confirmed by a colloidal iron stain that was positive for increased dermal mucin.
APPM, a distinct and rare variant of localized lichen myxedematosus, predominantly affects females. It presents with persistent, symmetric, smooth-surfaced small papules on the dorsal hands and wrists. To date, the etiopathogenesis remains unclear. While primarily considered a cutaneous condition, an isolated case related to IgA monoclonal gammopathy has been reported.
Notably, APPM, unlike other lichen myxedematosus forms, is a benign disorder devoid of associations with systemic abnormalities such as thyroid disorders or gammopathy. However, TSH levels and a serum protein electrophoresis (SPEP) test are still recommended for precautionary purposes. Despite its persistent nature, APPM does not typically resolve spontaneously. Thus, this patient's condition warrants observation and can be treated with topical calcineurin inhibitors, intralesional Kenalog, or electrocoagulation. Unfortunately, these reported treatments have generally been unsuccessful, which highlights the need for continued investigation into novel therapeutic modalities for APPM.