Cutaneous mucinosis of infancy: is it a real entity or the paediatric form of lichen myxoedematosus (papular mucinosis)?

[Cutaneous mucinosis of infancy]

Die kutane Muzinose der Kindheit ist eine sehr seltene Hauterkrankung mit nur wenigen beschriebenen Fällen in der Literatur. Wir berichten über einen 11-jährigen Jungen mit seit 9 Monaten bestehenden, asymptomatischen, hautfarbenen Papeln und Plaques am rechten Arm. Histologisch zeigten sich dermal und tief dermal zwischen den Kollagenbändern ausgeprägte Muzinablagerungen und Fibroblastenproliferationen. Da es sich bei der kutanen Muzinose der Kindheit um eine benigne Erkrankung mit guter Prognose handelt, ist eine Therapie nicht notwendig.

Lichen myxedematosus: a rare group of cutaneous mucinosis

Cutaneous mucinoses are a heterogeneous group of dermatoses in which excess deposition of mucin in the dermis gives the skin a waxy appearance, with papules and plaques that can vary from self-healing mucinosis to even disrupting the normal shape of a patient's face, conferring a leonine facies, or be part of life threatening diseases like scleromyxedema. This review will describe the most recent classification on lichen myxedematosus in the generalized (scleromyxedema) and the localized forms, as well as the different organ systems involved in scleromyxedema, diagnostic workup, current management, and prognosis.

Cutaneous Mucinosis of Infancy: A Rare Congenital Case with Coexisting Progressive, Eruptive, and Spontaneously Involuting Lesions

Cutaneous mucinosis in infancy is rare. We report an infant with multiple congenital papules distributed over the trunk, neck, and extremities. These papules were mainly dispersed, but they also coalesced into plaques. Histopathologic findings showed features of cutaneous mucinosis of infancy (CMI). Over 2 years of follow-up, we observed that the preexisting lesions on the lower back and left trunk progressively increased in size, and a few new scattered papules continued to appear, mainly on the trunk; several lesions spontaneously resolved with no further complications. CMI is considered to be a persistent cutaneous disorder, even though spontaneously regressing cases have rarely been reported. This case demonstrates the broad clinical spectrum of CMI, with progressive, eruptive, and spontaneously involuting lesions all present in the same patient. This condition should be considered in the differential diagnosis of congenital or infantile-onset papules and plaques, especially those yellowish in color.

Nodular lesions of self-healing juvenile cutaneous mucinosis: a pitfall!

Self-healing juvenile cutaneous mucinosis (SHJCM) is a rare disorder of unknown origin, which occurs in children in good health. It is characterized by the multiplication of transient cutaneous papules and nodules, mainly located on the head and periarticular areas that spontaneously resolve. Histological features of SHJCM have been well described; therefore, the diagnosis is usually made easily when papules are biopsied. We report a series of 3 new cases of SHJCM presenting mainly with nodular lesions. Histological examination of these nodules showed either lesions consistent with nodular or proliferative fasciitis or nonspecific panniculitis. Mucinous deposits were present but often inconspicuous, so could be disregarded. We wanted to emphasize this misleading presentation because a biopsy for histological examination is always mandatory in cases of proliferating nodules to rule out malignant tumors. Therefore, the diagnosis always requires discussion between pathologists and clinicians to rapidly reassure the parents and avoid inappropriate therapy.

Scleromyxedema-like Syndrome With Systemic Involvement in a Cat

Scleromyxedema—the generalized form of lichen myxedematosus, a primary mucinosis—is a rare disease in human patients. It is characterized by dermal mucin deposits, increased numbers of fibroblasts, and variable fibrosis in the absence of thyroid disease. It is accompanied in 80% of cases by a monoclonal gammopathy. To date, scleromyxedema with systemic involvement has not been documented in domestic animals. This is the first report of a scleromyxedema-like syndrome in a cat, which had a substantial deposition of mucin in the dermis of the head and paws with a mild gammaglobulinemia of 2.25 g/dl (reference range, 1.39–2.22 g/dl). At necropsy, multiple nodules of connective tissue intermingled with mucin deposits were conspicuous on the surface of thoracic and abdominal organs. Such severe systemic accumulations of mucin have not been reported in human or veterinary medicine.

Discrete papular lichen myxoedematosus: a rare subtype of cutaneous mucinosis

Primary cutaneous mucinoses are characterized by abnormal mucin deposits in the skin. Discrete papular lichen myxoedematosus (DPLM) is an unusual subtype. Only 11 of the cases described in the literature to date showed no relation to human immunodeficiency virus (HIV) infection. We report a 21-year-old woman with numerous symmetrical asymptomatic papules on her trunk, arms and thighs. Results of investigations were normal. On histological examination, the upper dermis showed a focal mucin deposit. DPLM can be associated with HIV or C hepatitis virus (HCV) infection and therefore an early diagnosis is very important.

Lichen Myxedematosus (Papular Mucinosis): New Concepts and Perspectives for an Old Disease

Lichen myxedematosus (LM) is an idiopathic cutaneous mucinosis; its classification dates back to 1953, when Montgomery and Underwood distinguished 4 types of LM. In the literature, the terms LM, papular mucinosis, and scleromyxedema often have been 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. Actually, LM includes 2 clinicopathologic subsets: a generalized papular and sclerodermoid form (the only one which should be called scleromyxedema) with systemic, even lethal, manifestations and a localized form, which does not run a disabling course. The localized form is subdivided into 4 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) papular mucinosis of infancy, a pediatric variant of the discrete form or the acral form of persistent papular mucinosis; and (4) 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 subtypes, and (4) not well-specified cases.

Self-healing juvenile cutaneous mucinosis

Self-healing juvenile cutaneous mucinosis is an extremely uncommon disorder characterized by the acute eruption of multiple papules and subcutaneous nodules. In this report, we describe one of the youngest patients reported to date with self-healing juvenile cutaneous mucinosis and further define several of the histologic and clinical characteristics unique to the disorder. Awareness of this disease is important because, despite an ominous presentation, all reported cases have resolved spontaneously. Therefore, aggressive therapy should be avoided.