New and emerging conditions of acquired cutaneous mucinoses in adults.

Cutaneous mucinoses are a heterogenous group of conditions, characterized by the deposition of glycosaminoglycans (mucin) in the dermis, follicles, or in the epidermis. Major cutaneous mucinoses include lichen myxedematosus, scleredema, mucinoses associated with thyroid disease, reticular erythematous mucinosis, papulonodular mucinosis associated with connective tissue diseases, and cutaneous focal mucinosis. The aim of this review is to provide an update of what has currently been reported in the last 30-year literature about several new or emerging conditions of acquired cutaneous mucinoses in adults. Two new clinico-pathologic entities have been described: (i) Obesity-associated lymphedematous mucinosis and pretibial stasis mucinosis; (OACM) (ii) Nodular mucinosis of the breast (NMB). Two relatively new disease categories encompassing cutaneous mucinoses with a common pathogenetic mechanism have been identified: (i) Cutaneous mucinoses associated with drug exposure including biologic therapy, anti-colony-stimulating factor 1 receptor (CSF1R) and subcutaneous intralesional interferons (toxic dermal mucinoses); (ii) Cutaneous mucinosis following physical agents including mechanical traumas and after knee replacement.

Mosaic PRKACA duplication causing a novel and distinct phenotype of early-onset Cushing's syndrome and acral cutaneous mucinosis.

SIGNIFICANCE STATEMENT: We describe a mosaic PRKACA duplication in a young infant who presented with a Carney-like complex: bilateral non-pigmented micronodular adrenal hyperplasia, severe early-onset Cushing's syndrome, and distinct acral soft tissue overgrowth due to cutaneous mucinosis. This represents a novel manifestation of PRKACA disruption and broadens the extra-adrenal phenotype of PRKACA-associated Cushing's syndrome. Our data suggest that Cushing's syndrome phenotypes arising from somatic and germline PRKACA abnormalities can exist on a spectrum. We emphasise the value of ascertaining a genetic diagnosis for PRKACA-mediated adrenal and extra-adrenal disease to guide individualised and targeted care.

Obesity-associated lymphedematous mucinosis and stasis mucinosis.

Cutaneous dermal mucinoses are a group of conditions characterized by abnormal deposition of mucin (hyaluronic acid and sulfated glycosaminoglycans) in the dermis. They can be classified either as localized or generalized forms and occur primarily or secondarily to systemic disorders. Obesity-associated lymphedematous mucinosis and pretibial stasis mucinosis are uncommon and relatively newly recognized disorders occurring in obese patients or in patients with venous insufficiency. Clinically, patients present with papules and nodules progressing to plaques and arising in an erythematous and edematous basis on the legs, especially the shins. Histopathologic examination indicates mucin deposition in the superficial portion of the dermis, angioplasia with an increase in small blood and/or lymphatic vessels, vertically running vessels, slight fibrosis, and no inflammation. Laboratory workup and histopathologic testing are helpful in differentiating these entities from pretibial myxedema (thyroid dermopathy), which represents the main differential diagnosis. Obesity-associated lymphedematous mucinosis and stasis mucinosis are not different entities but belong to a spectrum of mucinoses secondary to an increased body mass index, chronic lymphedema, and/or chronic venous insufficiency.

Acral persistent papular mucinosis: A case report and summary of 24 Japanese cases.

Acral persistent papular mucinosis is a rare subtype of localized lichen myxedematosus. We report a case of a 41-year-old woman with acral persistent papular mucinosis. She had a 5-year history of multiple, scattered, whitish papules, on the back of both hands, of 2-5 mm in diameter. Histopathological examination revealed a focal, fairly circumscribed area with sparse collagen fibers in the upper and middle dermis. The circumscribed area was positively stained with Alcian blue. The papules were clinically and histologically diagnosed as acral persistent papular mucinosis. We also summarized 24 Japanese acral persistent papular mucinosis cases, including ours. Although acral persistent papular mucinosis occurs predominantly in women according to overseas reports, the male : female ratio is 5:7 in Japan. It has been reported that tranilast (N-[3,4-dimethoxycinnamoyl]-anthranilic acid) was effective in two Japanese cases. In our case, the patient had been treated with tranilast for 2 months without improvement. Further studies are required to confirm the efficacy of tranilast for acral persistent papular mucinosis.

Cutaneous mucinosis of infancy: a rare case of joint involvement.

BACKGROUND: Primary cutaneous mucinosis are a heterogeneous group of diseases characterized by the deposition of glycosaminoglycans in the dermis and the follicles. These diseases are rare in children therefore their diagnosis and management are still challenging. Joint involvement has been reported in patients with secondary cutaneous mucinosis and, rarely, in primary mucinosis. We describe a case of Cutaneous Mucinosis of Infancy with joint involvement. CASE PRESENTATION: An healthy 5-year-old boy showed acute arthritis of the left knee and left elbow confirmed by ultrasound. Laboratory tests were within normal range. Symptoms disappeared after a course of nonsteroid anti-inflammatory drugs. One year later, the knee swelling reappeared; juvenile idiopathic arthritis was diagnosed and intra-articular steroid injection was performed. Due to persistence of arthritis of the knee he was admitted to our hospital. On physical examination variable skin-colored lesions were observed, which had been in existence for over 2 years. We performed a skin biopsy that showed an interstitial mucine deposition in the reticular dermis. Cutaneous Mucinosis of Infancy was diagnosed. DISCUSSION AND CONCLUSIONS: Cutaneous Mucinosis of Infancy is a persistent dermatosis with benign prognosis and no treatment is generally required. Our case report is particularly interesting because it is the first in which joint involvement has been reported in CMI, a disorder that has so far been described as limited to skin involvement. Further studies will be necessary in order to clarify the pathogenesis of joint involvement in primary mucinosis.

Acute acral eruptions in children during the COVID-19 pandemic: Characteristics of 103 children and their family clusters.

BACKGROUND: A marked increase in frequency of acute acral eruptions (AAE) was observed in children during the COVID-19 pandemic in the spring period. OBJECTIVES: In this observational multicenter study, based on children with AAE, we aimed to assess the proportion of household members possibly infected by SARS-CoV-2. METHODS: We collected data from all children observed with AAE, prospectively from April 7, 2020 to June 22, 2020, and retrospectively since February 28, 2020. The primary outcome was the household infection rate, defined as the proportion of family clusters having at least one member with COVID-19 infection other than the child with AAE ("index child"). The definition of a case was based on characteristic clinical signs and a positive PCR or serology. RESULTS: The study included 103 children in 10 French departments and in Quebec. The median age was 13 years and the interquartile range [8-15], with a female-to-male ratio of 1/1.15. In children with AAE, all PCR tests were negative (n=18), and serology was positive in 2/14 (14.3%) cases. We found no significant anomalies in the lab results. A total of 66 of the 103 families (64.1%) of included children had at least one other infected member apart from the index child. The total number of household members was 292, of whom 119 (40.8%) were considered possibly infected by SARS-CoV-2. No index children or households exhibited severe COVID-19. DISCUSSION: Among the 103 households included, 64.1% had at least one infected member. Neither children with AAE nor their households showed severe COVID-19.

Oral focal mucinosis: A multi-institutional study and literature review.

BACKGROUND: Oral focal mucinosis (OFM) is a rare benign condition of unknown etiology, considered the oral counterpart of cutaneous focal mucinosis. We report the clinicopathologic features of 21 cases of OFM in conjunction with a review of the literature. METHODS: Clinical data were collected from the records of five oral and maxillofacial pathology services. All cases were evaluated by hematoxylin and eosin staining, histochemistry, and immunohistochemistry (vimentin, S-100, α-SMA, CD34, and mast cell). RESULTS: The series comprised 14 females (66.7%) and seven males (33.3%), with a mean age of 48.2 ± 20.7 years (range: 8-77 years) and a 2:1 female-to-male ratio. Most of the lesions affected the gingiva (n = 6, 28.6%) and presented clinically as asymptomatic sessile or pedunculated nodules with fibrous or hyperplasic appearance. All cases were negative for S-100 protein, CD34, and α-SMA and positive for Alcian blue staining. Conservative surgical excision was the treatment in all cases, and there was only one recurrence. CONCLUSION: OFM is a rare benign disorder that is often clinically misdiagnosed as reactive lesions or benign proliferative processes. Dermatologists and pathologists should consider OFM in the differential diagnosis of soft tissue lesions in the oral cavity, mainly located in the gingiva.

[Cutaneous mucinosis of infancy]. / Kutane Muzinose der Kindheit.

Cutaneous mucinosis of infancy is a rare skin disease with just a few reported cases in the literature. We report the case of an 11-year-old boy with asymptomatic, skin-coloured papules and plaques on his right arm that had appeared 9 months prior to presentation. Histology showed a dermal and deep dermal interstitial mucin deposition and fibroblast proliferation. However, because cutaneous mucinosis of infancy is a benign disease with a good prognosis, therapy is not mandatory.

Diffuse dermal mucinosis secondary to colony-stimulating factor 1 receptor monoclonal antibody treatment: A novel and peculiar drug-induced diffuse cutaneous mucinosis.

Colony-stimulating factor 1 receptor (CSF1R) inhibitors represent a new class of immune-modulatory drugs, mostly investigated in clinical trials in different malignant neoplasms. Four patients, diagnosed with recurrent or advanced malignant neoplasm and treated with a combination of anti-programmed death ligand 1 and anti-CSF1R monoclonal antibodies, developed an asymptomatic cutaneous eruption characterized by an ill-defined pseudoedematous to waxy diffuse infiltration with a reticular cobblestone-like pattern. Histopathological examination revealed diffuse mucin deposition involving the superficial and mid-dermis with fragmented and scattered elastic fibers. The exact pathogenic mechanisms implicated in the development of mucin deposits in patients treated with CSF1R inhibitors remain to be elucidated. A reduced degradation and clearance of components of the extracellular matrix by macrophages secondary to CSF1 pathway inhibition may be hypothesized. Shredding and fragmentation of elastic fibers may be a result of the increased accumulation of mucopolysaccharides. This observation illustrates the new spectrum of skin-related toxicities secondary to new targeting therapies. This may contribute to a better understanding of the underlying pathogenic mechanisms in skin diseases characterized by a persistent dermal glycosaminoglycan deposition.

Plaque-like cutaneous mucinosis of childhood.

A healthy 10-year-old boy presented with plaque-like cutaneous mucinosis (PCM) on his back. Cutaneous biopsy was followed by progressive resolution of the skin lesion. Pediatric PCM could differ clinically from the adult form. However, more cases are necessary to draw conclusions.

Reticular erythematous mucinosis: Literature review and case report of a 24-year-old patient with systemic erythematosus lupus.

Reticular erythematous mucinosis (REM) was first described 50 years ago, but only around 100 case reports in English have been published. Its relation with other inflammatory skin disorders is still being debated. We report a case of REM, including the clinical and histopathological findings. Also, a systematic review of 94 English-language reported cases is provided. The described criteria for clinical and histopathological diagnosis are highlighted in order to REM can be confidently diagnosed.