Hematoxylin-eosin–stained sections showed a papule containing a poorly circumscribed collection of widely separated collagen bundles in the upper dermis. Colloidal iron staining (Figure 4) confirmed the presence of an extensive dermal mucin deposition, which had produced the lesion.
Acral persistent papular mucinosis, which was first described in 1986 by Rongioletti et al,1 is 1 of 5 subtypes of the localized papular form of lichen myxedematosus that were described in Rongioletti and Rebora's2 recently updated classification of papular mucinosis, lichen myxedematosus, and scleromyxedema. It is rare, with only 17 cases reported to date. The female-male ratio is 4.7:1. Patients present with multiple, asymptomatic, noncoalescing, skin-colored papules that are limited in distribution to the extensor surfaces of the hands and wrists. There may be some extension to the forearms, but the trunk and the proximal aspect of the extremities are not involved. Sclerotic features are absent.