Acral persistent papular mucinosis

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.

Acral persistent papular mucinosis: a case report and literature review

Acral persistent papular mucinosis is a rare subtype of localized lichen myxedematosus. It shows symmetric, asymptomatic, chronic, ivory to flesh-colored, 2-5 mm sized papules arranged on the dorsa of the hands and extensor aspects of the distal forearms. Thirty-two cases including two from China, appear to fit the proposed diagnostic criteria. We report a 31-year-old Chinese woman who presented with papules on the extensor aspects of her hands and distal forearms. Histopathology revealed a circumscribed area in the upper and mid reticular dermis with splaying of collagen fibers caused by amorphous deposits. The material was mucin, as it stained positively with alcian blue at pH 2.5. The thyroid profile was normal, and there was no evidence for lupus erythematous. The lesions were treated with electrofulguration and resolved leaving mild scars; there has been no recurrence at follow-up after one year. We also review the literature on this rare form of mucinosis.

Acral persistent papular mucinosis

Acral persistent papular mucinosis is a rare subtype of localized lichen myxedematosus. For half a century, this disease has endured a controversial and constantly evolving classification. We describe a patient who presented with discrete, flesh-colored papules on the hands, wrists, and forearms in a distribution consistent with acral persistent papular mucinosis. Histology was also constant with this disease, showing a well-circumscribed deposition of mucin in the upper and mid dermis that spared a small grenz zone. The changing nomenclature and diagnostic requirements of acral persistent papular mucinosis that have allowed it to remain a topic of debate are examined through a comprehensive review of the literature. All reported cases are reviewed.

Updated classification of papular mucinosis, lichen myxedematosus, and scleromyxedema

Lichen myxedematosus (LM) is an idiopathic cutaneous mucinosis; its classification dates back to 1953, when Montgomery and Underwood distinguished 4 types of LM: a generalized lichenoid eruption, later called scleromyxedema, a discrete papular form, a localized or generalized lichenoid plaque form, and an urticarial plaque form. In the literature, the terms LM, papular mucinosis, and scleromyxedema have been often used indiscriminately as synonyms, but most reported cases of LM or papular mucinosis without indication of the subtype appear in fact to be cases of scleromyxedema. On the basis of personal experience, the anatomoclinical manifestations of published cases of LM, papular mucinosis, and scleromyxedema are reviewed to distinguish clearly between a generalized form with systemic, even lethal, manifestations and a localized form, which does not run a disabling course. LM includes two clinicopathologic subsets: a generalized papular and sclerodermoid form (also called scleromyxedema) and a localized papular form. Diagnosis of scleromyxedema should fulfill the following criteria: (1) generalized papular and sclerodermoid eruption; (2) mucin deposition, fibroblast proliferation, and fibrosis; (3) monoclonal gammopathy; and (4) the absence of thyroid disease. The criteria for localized LM are as follows: (1) papular or nodular/plaque eruption; (2) mucin deposition with variable fibroblast proliferation; and (3) the absence of both monoclonal gammopathy and thyroid disease. The localized form is subdivided into 5 subtypes: (1) a discrete papular form involving any site; (2) acral persistent papular mucinosis involving only the extensor surface of the hands and wrists; (3) self-healing papular mucinosis, of a juvenile and an adult type; (4) papular mucinosis of infancy, a pediatric variant of the discrete form or of acral persistent papular mucinosis; and (5) nodular form. A third group of atypical or intermediate forms, not meeting the criteria for either scleromyxedema or the localized form, includes cases of (1) scleromyxedema without monoclonal gammopathy, (2) localized forms with monoclonal gammopathy and/or systemic symptoms, (3) localized forms with mixed features of the 5 subtypes, and (4) not well-specified cases.

Cutaneous mucinous nodules associated with proliferating synovitis of rheumatoid arthritis

Rheumatoid arthritis (RA) is occasionally associated with specific or non-specific cutaneous conditions. In this report, we describe unusual cutaneous nodules arising on the skin overlying the inflamed joints of two patients with RA. The nodules were histopathologically characterized by mucinous granulation tissue associated with neutrophilic infiltration and proliferation of starry-shaped mesenchymal cells. The affected joints of both cases showed synovitis with synovial tissue hyperplasia due to RA. Because hyaluronic mucin, which is the major component of synovial fluids, was deposited in the nodules, intradermal inoculation of synovial cells seemed to be responsible for the nodular development. The nodules of one patient spontaneously resolved in several months. We are unaware of any report describing similar cases. Such nodules should be included as a cutaneous complication of RA, distinct from neoplasias.