Clinical aspects of paediatric mastocytosis: a review of 101 cases

Dermatologic manifestations of hematologic disorders

Distinguishing key morphologic features and understanding the pathophysiology of common cutaneous manifestations of hematologic disorders is essential to ensure prompt and appropriate treatment. In fact, classic cutaneous signs may provide the first clue to the diagnosis of an underlying hematologic disease. Disorders of coagulation, vascular abnormalities, or cutaneous infiltration and deposition are responsible for the underlying pathophysiology of cutaneous manifestations in the majority of cases. Hematologists often feel ill-equipped in identifying morphologic changes in the skin. Thus, the purpose of this review is to provide a comprehensive overview of classic cutaneous manifestations and diagnostic considerations of the associated hematologic conditions. Though there is a specific focus on non-malignant disorders, those straddling the spectrum of malignancy are also discussed. In many disease states, the skin may serve as an important marker of an emerging hematologic disorder, so close collaboration and multidisciplinary input remain essential to provide optimal and timely care for these patients.

Diffuse Cutaneous Mastocytosis: A Current Understanding of a Rare Disease

Mastocytosis is a heterogeneous disease characterized by the expansion and accumulation of neoplastic mast cells in various tissues. Diffuse cutaneous mastocytosis (DCM) is a rare and most severe form of cutaneous mastocytosis, which typically occurs in childhood. There have been reports of a familial DCM with specific gene mutations, indicating both sporadic and hereditary factors involved in its pathogenesis. DCM is associated with severe MC mediator-related symptoms and an increased risk of anaphylaxis. The diagnosis is based on the appearance of skin lesions, which typically show generalized thickening, erythroderma, blistering dermographism, and a positive Darier's sign. Recognition, particularly in infants, is challenging due to DCMs resemblance to other bullous skin disorders. Therefore, in unclear cases, a skin biopsy is crucial. Treatment focuses on symptom management, mainly including antihistamines and mast cell stabilizers. In extremely severe cases, systemic steroids, tyrosine kinase inhibitors, phototherapy, or omalizumab may be considered. Patients should be equipped with an adrenaline autoinjector. Herein, we conducted a comprehensive review of literature data on DCM since 1962, which could help to better understand both the management and prognosis of DCM, which depends on the severity of skin lesions, intensity of mediator-related symptoms, presence of anaphylaxis, and treatment response.

Large Congenital Cutaneous Mastocytoma Presenting With Recurrent Persistent Blistering: A Case Report

Congenital cutaneous mastocytoma is an uncommon disorder characterized by abnormal proliferation of mast cells. It typically presents as a single, small, yellowish-brown plaque, and its diagnosis is generally facilitated by distinctive clinical features, including a positive Darrier's sign. This report presents a case of an unusually large, solitary congenital mastocytoma encompassing nearly the entire circumference of the calf, observed in a newborn boy of Bangladeshi origin. Measuring 13x6 cm, the lesion formed large bullae and subsequent erosions. The perplexing clinical appearance prompted a skin biopsy, revealing monomorphic CD117 (c-KIT) positive infiltration without significant cell pleomorphism, confirming the diagnosis of cutaneous mastocytoma. The patient underwent management with potent and very potent topical steroids, oral antihistamines, and non-adhesive dressings, remaining under long-term follow-up with secondary care dermatology. In reporting this case, our objective is to augment the existing scientific literature by providing additional evidence that cutaneous mastocytomas can display a spectrum of clinical presentations, as illustrated in this case.

An Unusual Transition from Cutaneous to Systemic Mastocytosis in a Pediatric Patient

Background: Cutaneous mastocytosis (CM) occurs when abnormal mast cells accumulate in the skin, whereas in systemic mastocytosis (SM), accumulation also occurs in other tissues. A transition from CM to SM is an atypical occurrence in pediatric patients. Case Presentation: An 8-month-old female presented with a 3-month history of whole body hyperpigmented macules with a normal serum tryptase level, consistent with a diagnosis of CM. At age 2.5 years, cutaneous lesions increased and repeat serum tryptase levels were elevated. Subsequent positive peripheral blood KIT D816V mutation testing furthered concern for a monoclonal mast cell disorder; therefore, prompting a bone marrow biopsy which was consistent with a diagnosis of SM. Conclusion: Our case depicts the possible transition from CM to SM in a pediatric patient. Despite an initial presentation consistent with a diagnosis of CM, watchful monitoring for signs and symptoms indicative of systemic involvement may be warranted in some pediatric patients.

Pediatric and Hereditary Mastocytosis

To a large extent, the clinical picture of pediatric mastocytosis depends on the age at which it is diagnosed. A neonate with diffuse cutaneous mastocytosis may frequently present in a severe state requiring treatment. Toddlers may require long-term anti-mediator therapy, and this may lead to concerns such as organizing preschool education due to the need for epinephrine injections. A teenager may have to face cutaneous disease persistence or a diagnosis of systemic mastocytosis. Further studies are needed to refine the available treatment options and prognosis for different age groups.

The Role of Mast Cells in the Induction and Maintenance of Inflammation in Selected Skin Diseases

Under physiological conditions, skin mast cells play an important role as guardians that quickly react to stimuli that disturb homeostasis. These cells efficiently support, fight infection, and heal the injured tissue. The substances secreted by mast cells allow for communication inside the body, including the immune, nervous, and blood systems. Pathologically non-cancerous mast cells participate in allergic processes but also may promote the development of autoinflammatory or neoplastic disease. In this article, we review the current literature regarding the role of mast cells in autoinflammatory, allergic, neoplastic skin disease, as well as the importance of these cells in systemic diseases with a pronounced course with skin symptoms.

Mastocytosis in children: a single-center long-term follow-up study

BACKGROUND

Mastocytosis is a heterogeneous group of rare disorders characterized by the accumulation of clonal mast cells in organs such as the skin and bone marrow. The diagnosis of cutaneous mastocytosis (CM) is based on clinical findings, positive Darier's sign, and histopathology, if necessary.

METHODS

Medical records of 86 children with CM diagnosed during a 35-year long period were reviewed. Most patients (93%) developed CM during the first year of life (median age 3 months). Clinical features at presentation and during the follow-up period were analyzed. Baseline serum tryptase level was measured in 28 patients.

RESULTS

A total of 85% of patients had maculopapular cutaneous mastocytosis/urticaria pigmentosa (MPCM/UP), 9% had mastocytoma, and 6% had diffuse cutaneous mastocytosis (DCM). Boy to girl ratio was 1.1:1. Fifty-four of 86 patients (63%) were followed from 2 to 37 years (median 13 years). Complete resolution was registered in 14% of mastocytoma cases, 14% of MCPM/UP, and in 25% of DCM patients. After the age of 18, skin lesion persisted in 14% mastocytoma, 7% MCPM/UP, and 25% children with DCM. Atopic dermatitis was diagnosed in 9.6% of patients with MPCM/UP. Three of 28 patients had elevated serum tryptase. Prognosis in all patients was good, and there were no signs of progression to systemic mastocytosis (SM).

CONCLUSION

To the best of our knowledge, our results represent the longest single-center follow-up study of childhood-onset CM. We found no complications of massive mast cell degranulation or progression to SM.

Mastocytosis in the Skin: Disease Heterogeneity among Children and Adults

Abstract is missing (Short communication)

Clinical and Demographic Characteristics of Cutaneous Mastocytosis in Childhood: Single-center Experience

INTRODUCTION

Mastocytosis is a rare and heterogenous disease, and in children it is generally limited to the skin and tends to regress spontaneously in adolescence.

AIM

In this study, demographic, clinical, and laboratory characteristics of pediatric patients with mastocytosis, and also coexisting diseases were investigated.

RESULTS

A total of 61 pediatric patients were included in the study. The male-to-female ratio was 2.2, the median age was 2 years (range, 0.25 to 19 y), and the median follow-up period was 2.0 years (range, 0.25 to 19 y). Types of clinical presentation at diagnosis consisted of mainly urticaria pigmentosa (45.9%). Seven patients were further investigated with suspicion of systemic mastocytosis, they were followed up, median of 9 years (range, 2.5 to 16 y), and none of them developed systemic disease. Coexisting allergic diseases were recorded in total 5 patients (8.2%). Three patients had immunoglobulin A deficiency, 1 patient had elevated immunoglobulin E level. A patient developed mature B-cell lymphoma with a heterozygous mutation in c-KIT exon 11.

DISCUSSION

Cutaneous mastocytosis in children may present as a complex disease with different clinical signs and symptoms. Standardized clinical criteria and guidelines for the follow-up of children with mastocytosis are required.

Pediatric Mastocytosis: An Update

Mastocytosis is a rare clonal disorder characterized by excessive proliferation and accumulation of mast cells (MC) in various organs and tissues. Cutaneous mastocytosis (CM), the most common form in children, is defined when MC infiltration is limited to the skin. In adults, the most common form is systemic mastocytosis (SM), characterized by MC proliferation and accumulation in organs, such as bone marrow, lymph nodes, liver, and spleen.1 Genetic aberrations, mainly the KIT D816V mutation, play a crucial role in the pathogenesis of mastocytosis, enhancing MC survival and subsequent accumulation in organs and tissues.2,3 CM includes three forms: solitary mastocytoma, maculopapular cutaneous mastocytosis (MPCM), and diffuse cutaneous mastocytosis (DCM). In most children with CM, skin lesions regress spontaneously around puberty; unfortunately, it is not always a self-limiting disease.4 Even if SM occurs occasionally, all children with mastocytosis require planned follow-up over time. Children with mastocytosis often suffer from MC mediator-related symptoms, the most common of which is itching, often triggered by rubbing the lesions. Management of pediatric mastocytosis is mainly based on strict avoidance of triggers. Treatment with H1 and H2 histamine receptor blockers on demand and the availability of epinephrine auto-injectors for the patients to use in case of severe anaphylactic reactions are recommended.

Role of Mast Cells in the Pathogenesis of Pruritus in Mastocytosis

Pruritus can be defined as an unpleasant sensation that evokes a desire to scratch and significantly impairs patients' quality of life. Pruritus is widely observed in many dermatoses, including mastocytosis, a rare disease characterized by abnormal accumulation of mast cells, which can involve skin, bone marrow, and other organs. Increasing evidence highlights the role of mast cells in neurogenic inflammation and itching. Mast cells release various pruritogenic mediators, initiating subsequent mutual communication with specific nociceptors on sensory nerve fibres. Among important mediators released by mast cells that induce pruritus, one can distinguish histamine, serotonin, proteases, as well as various cytokines. During neuronal-induced inflammation, mast cells may respond to numerous mediators, including neuropeptides, such as substance P, neurokinin A, calcitonin gene-related peptide, endothelin 1, and nerve growth factor. Currently, treatment of pruritus in mastocytosis is focused on alleviating the effects of mediators secreted by mast cells. However, a deeper understanding of the intricacies of the neurobiology of this disease could help to provide better treatment options for patients.

Clinicopathological Profile of Childhood Onset Cutaneous Mastocytosis from a Tertiary Care Center in South India

Background

Mastocytosis is characterized by clonal proliferation of mast cells in various organs and can have isolated cutaneous or systemic involvement. Childhood-onset mastocytosis (COM) is usually cutaneous and regresses spontaneously, while adult-onset mastocytosis (AOM) is often persistent with systemic involvement. There is limited data on COM from India.

Objective

To elucidate the clinicopathological profile of COM.

Methods

We conducted a retrospective chart review of all the patients with histologically proven COM (≤16 years), presenting over 11 years (January 2009 to December 2019) to the Dermatology Department. We compiled the demographic data, clinical characteristics (morphology, extent, distribution), laboratory investigations, histopathology findings, imaging (ultrasound abdomen), c-KIT mutation results, where available, and other associated abnormalities, and grouped them according to the WHO classification for mastocytosis.

Results

Among the 66 patients with COM (M: F-1.6:1), 89.4% had onset before 2 years of age. The subtypes were: maculopapular cutaneous mastocytosis (MPCM: 44, 66.7%); mastocytoma of the skin (MOS: 19, 28.8%); diffuse cutaneous mastocytosis (DCM: 2, 3%) and indolent systemic mastocytosis (ISM: 1, 1.5%). Blistering was observed in 29 (43.9%) and Darier sign was elicited in 47 (71.2%) patients. Serum tryptase was elevated in 9/21 (42.9%) patients, but none had systemic mastocytosis. Three patients had c-KIT mutations (two in exon 8 and one in exon 17). Most patients were managed symptomatically and the patient with ISM improved with imatinib.

Conclusion

MPCM is the most common variant of COM and most patients had a disease onset before 2 years. Overall, COM had a good prognosis with rare systemic involvement, mitigating the need for extensive evaluation routinely in children.

Decoding the intricacies of the mast cell compartment

Historically, understanding of the human mast cell (MC) compartment has lagged behind the appreciation of other cell lineages. MCs exist in vascularised tissues but do not under normal circumstances circulate in blood, and there has been no pharmacological agent identified that totally and selectively inhibits human MC function. There are no substantiated accounts of an apparently healthy individual who is severely lacking in MCs. Thus, some of the approaches employed to understand the function of a specific immune cell are not available to the MC biologist. The disease categories that have provided the greatest insight into MC biology have been monoclonal and IgE-mediated MC disorders. This has led to the categorisation of MC diseases as intrinsic or extrinsic to the MC compartment and to the recognition of the role of mediators in MC activation disorders. Mastocytosis as a clonal disorder not only impacts the MC compartment through changes intrinsic to the MC, but also by the effects of episodes of significant release of MC mediators. The availability of newer therapeutic approaches developed to treat monoclonal MC disorders offer insights into how to more selectively approach management of MC centric diseases.

Mediator-Related Symptoms and Anaphylaxis in Children with Mastocytosis

Mastocytosis is characterized by the pathological accumulation of mast cells (MC) in various organs. In these patients, MC may degranulate and thereby contribute to clinical symptoms, especially when a concomitant allergy is present. However, MC activation can not only be induced by high-affinity receptors for IgE, but also by anaphylatoxins, neuropeptides, IgG immune complexes, complement-components, drugs, products of bacteria or parasites, as well as physical factors such as heat, cold, vibration, stress, sun, or physical effort. Symptoms due to mediators released by activated MC may develop in adults suffering from systemic mastocytosis, but also evolve in children who usually have cutaneous mastocytosis (CM). Clinically, CM is otherwise characterized by typical brown, maculopapular skin lesions or mastocytoma associated with a positive Darier's sign. Pruritus and flushing are common and blistering may also be recorded, especially in diffuse CM (DCM). Pediatric patients with mastocytosis may also have gastrointestinal, respiratory, and neurologic complaints. Although anaphylaxis is not a typical finding, pediatric patients with massive skin involvement and high tryptase levels have a relatively high risk to develop anaphylaxis. This paper reviews MC mediator-related symptoms and anaphylaxis in children with mastocytosis, with special emphasis on risk factors, triggers, and management.

Molecular Background, Clinical Features and Management of Pediatric Mastocytosis: Status 2021

Pediatric mastocytosis is a heterogeneous disease characterized by accumulation of mast cells in the skin and less frequently in other organs. Somatic or germline mutations in the KIT proto-oncogene are detected in most patients. Cutaneous mastocytosis is the most common form of the disease in children. In the majority of cases, skin lesions regress spontaneously around puberty. However, in few patients, mastocytosis is not a self-limiting disease, but persists into adulthood and can show signs of systemic involvement, especially when skin lesions are small-sized and monomorphic. Children with mastocytosis often suffer from mast cell mediator-related symptoms. Severe hypersensitivity reactions can also occur, mostly in patients with extensive skin lesions and blistering. In a substantial number of these cases, the triggering factor of anaphylaxis remains unidentified. Management of pediatric mastocytosis is mainly based on strict avoidance of triggers, treatment with H1 and H2 histamine receptor blockers, and equipment of patients and their families with epinephrine auto-injectors for use in severe anaphylactic reactions. Advanced systemic mastocytosis occurs occasionally. All children with mastocytosis require follow-up examinations. A bone marrow investigation is performed when advanced systemic mastocytosis is suspected and has an impact on therapy or when cutaneous disease persists into adulthood.

Pediatric Mastocytosis: Recognition and Management

Mastocytosis is a heterogeneous group of disorders characterized by the accumulation of clonal mast cells in organs such as the skin and bone marrow. In contrast to adults, most affected children have only cutaneous involvement. This article reviews the molecular pathogenesis, skin findings, mast cell mediator-related symptoms, evaluation, and management of childhood-onset mastocytosis, noting differences from adult-onset disease. Current classification of cutaneous mastocytosis and the natural histories of different variants in pediatric patients are highlighted, with a focus on clinical manifestations with prognostic implications. A practical algorithm is provided to guide clinical assessment, laboratory and other investigations, and longitudinal monitoring, including recognition of hepatosplenomegaly as a marker of systemic disease and utilization of allele-specific quantitative PCR (ASqPCR) to detect KIT mutations in the peripheral blood. Updated information and consensus-based recommendations regarding possible triggers of mast-cell degranulation (e.g., physical, medications) are discussed, with an emphasis on patient-specific factors and avoiding excessive parental concern. Lastly, an individualized, stepwise approach to treatment of symptoms, skin-directed therapy, and potential use of kinase inhibitors for severe systemic disease is outlined.

Clinical Impact of Skin Lesions in Mastocytosis: A Multicenter Study of the European Competence Network on Mastocytosis

Mastocytosis is a rare neoplasm characterized by the expansion and accumulation of mast cells in various organ systems. Systemic mastocytosis (SM) may or may not present with cutaneous lesions. To examine the frequency and clinical impact of cutaneous involvement, data on 1,510 patients with mastocytosis collected in the registry of the European Competence Network on Mastocytosis were analyzed. Cutaneous involvement was found in 1,195 of 1,510 patients (79.1%). Of these, 286 had cutaneous mastocytosis, and 721 had SM with skin involvement. Adult patients with skin involvement who did not have a bone marrow examination (n = 188) were defined as having mastocytosis in the skin. In 315 patients, SM without skin involvement was found. The percentage of cases with cutaneous involvement was higher in indolent SM (100%) and smoldering SM (87.9%) compared to aggressive SM (46.8%) or mast cell leukemia (38.5%). After a median follow-up of 5.6 years, no patient with cutaneous mastocytosis had died, but 2.6% of the patients with mastocytosis in the skin, 5.7% of the patients with SM with skin involvement, and 28.95% of the patients with SM without skin involvement had died. Overall survival was longer in patients with skin involvement (cutaneous mastocytosis and/or mastocytosis in the skin and/or SM with skin involvement) than in patients with SM without skin involvement (P < 0.0001). These data argue for a thorough examination of both the skin and bone marrow in adult patients with mastocytosis.

Clinical Impact of Inherited and Acquired Genetic Variants in Mastocytosis

Mastocytosis is a rare and complex disease characterized by expansion of clonal mast cells (MC) in skin and/or various internal organ systems. Involvement of internal organs leads to the diagnosis of systemic mastocytosis (SM). The WHO classification divides SM into indolent SM, smoldering SM and advanced SM variants, including SM with an associated hematologic neoplasm, aggressive SM, and MC leukemia. Historically, genetic analysis of individuals with pure cutaneous mastocytosis (CM) and SM have focused primarily on cohort studies of inherited single nucleotide variants and acquired pathogenic variants. The most prevalent pathogenic variant (mutation) in patients with SM is KIT p.D816V, which is detectable in most adult patients. Other somatic mutations have also been identified-especially in advanced SM-in TET2, SRSF2, ASXL1, RUNX1, CBL and JAK2, and shown to impact clinical and cellular phenotypes. Although only small patient cohorts have been analyzed, disease associations have also been identified in several germline variants within genes encoding certain cytokines or their receptors (IL13, IL6, IL6R, IL31, IL4R) and toll-like receptors. More recently, an increased prevalence of hereditary alpha-tryptasemia (HαT) caused by increased TPSAB1 copy number encoding alpha-tryptase has been described in patients with SM. Whereas HαT is found in 3-6% of general Western populations, it is identified in up to 17% of patients with SM. In the current manuscript we review the prevalence, functional role and clinical impact of various germline and somatic genetic variants in patients with mastocytosis.

Criteria for the Regression of Pediatric Mastocytosis: A Long-Term Follow-Up

BACKGROUND

Mastocytosis is a neoplastic condition characterized by the accumulation of mast cells (MCs) in 1 or more organ. Adults tend to have persistent, systemic mastocytosis, whereas MC infiltration in children is usually limited to the skin and typically regresses after several years. Both adults and children could display mast cell activation symptoms (MCASs) due to MC mediator release. In more than 85% of both adult and pediatric cases, KIT mutations are present, with the KIT D816V mutation being present in most affected adults but in only half the affected children.

OBJECTIVE

To identify the clinical, biological, and molecular factors associated with the regression of cutaneous mastocytosis (CM) in children, and to assess the correlation between MCASs and CM regression.

METHODS

Patients having suffered from pediatric-onset mastocytosis for at least 8 years were included in a longitudinal cohort study. Clinical data, the baseline serum tryptase level, the KIT sequence, and the progression of MCASs and CM were recorded.

RESULTS

CM regressed in 210 of the 272 included patients (77.2%; mean time to regression, 6.10 years). The rare cases of aggressive systemic mastocytosis were symptomatic from the outset. Congenital mastocytosis and the KIT D816V mutation were associated with CM regression (odds ratio, 0.48, P = .031, and 0.173, P = .031, respectively). Aggravation of MCASs over time was correlated with the persistence of skin lesions. However, the MCASs became more intense in 19% of the patients with MCASs at baseline and CM regression, justifying long-term follow-up in this setting.

CONCLUSIONS

Our results open up new hypotheses with regard to the spontaneous regression of CM in pediatric patients.

Cutaneous mastocytosis: A dermatological perspective

Mastocytosis is a rare disease characterised by expansion and collection of clonal mast cells in various organs including the skin, bone marrow, spleen, lymph nodes and gastrointestinal tract. The prevalence of mastocytosis has been estimated to be one in 10 000, while the estimated incidence is one per 100 000 people per year. Cutaneous mastocytosis is classified into (i) maculopapular cutaneous mastocytosis, also known as urticaria pigmentosa; (ii) diffuse cutaneous mastocytosis; and (iii) mastocytoma of the skin. In adults, cutaneous lesions are usually associated with indolent systemic mastocytosis and have a chronic evolution. Paediatric patients, on the contrary, have often cutaneous manifestations without systemic involvement and usually experience a spontaneous regression. Diagnosis of cutaneous mastocytosis may be challenging due to the rarity of the disease and the overlap of cutaneous manifestations. This short review describes pathogenesis and clinical aspects of cutaneous mastocytosis with a focus on diagnosis and currently available therapies.

How "benign" is cutaneous mastocytosis? A Danish registry-based matched cohort study

BACKGROUND

There are limited estimates of the incidence rates (IRs) of mastocytosis, and only a few studies have addressed the long-term consequences of living with these diagnoses. Previous reports have shown that systemic mastocytosis is associated with leukemic transformations and an increased risk of death as opposed to cutaneous mastocytosis (CM) and indolent systemic mastocytosis (ISM), which have benign diagnoses with life expectancy rates similar to those of the background population.

OBJECTIVE

This study aimed to analyze the incidence and mortality of mastocytosis.

METHODS

A population-based matched cohort study of patients with mastocytosis between 1 January 1, 1977 and 31 December 31, 2014 was identified from the Danish National Health Registries. IRs of CM, ISM, and pediatric mastocytosis were highlighted. Survival estimates were compared with those of a healthy background population, using a Cox proportional hazard model.

RESULTS

A total of 1461 patients with mastocytosis were identified. The annual IR of overall mastocytosis was 1.1 per 100,000 person years (95% confidence interval [CI], 1.0-1.2). Among children, the IR was 1.8 per 100,000 person years (95% CI, 1.6-2.1). The prevalence of any comorbidity was twice as high among patients with mastocytosis compared with the population without mastocytosis (odds ratio: 2.1; 95% CI, 1.8-2.5). The Charlson Comorbidity Index-adjusted mortality among adult patients with mastocytosis was HRCutaneous Mastocytosis 1.2 (95% CI, 0.8-1.9), HRIndolent Systemic Mastocytosis 1.9 (95% CI 1.4-2.5), and HRSystemic Mastocytosis 4.2 (95%, CI 1.9-9.4), respectively.

CONCLUSION

Based on an entire nation, with free health care at the point of access, we estimated an annual IR of mastocytosis and its subgroups. We discovered that patients with ISM had an increased risk of death compared with the general population. Our data supported the overall benign nature of CM diagnosed after age 2 years.

c-KIT-Positive Fatal Diffuse Cutaneous Mastocytosis With Systemic Manifestations in a Neonate

Diffuse cutaneous mastocytosis is a rare variant of mastocytosis in the neonatal period. We describe a case of c-KIT (DV) mutation-positive fatal diffuse cutaneous mastocytosis with systemic involvement of the gastrointestinal tract and associated malabsorption and hepatosplenomegaly associated with mast cell mediator release symptoms.

Diffuse cutaneous mastocytosis: Case report and literature review

A 6-month-old boy was referred to our burn unit with a recurrent bullous dermatitis, fever, and emesis, originally diagnosed as staphylococcal scalded skin syndrome (SSSS) at an outside hospital. Infectious workup was negative and shave biopsy revealed a dense, diffuse dermal infiltrate of mast cells, consistent with diffuse cutaneous bullous mastocytosis-a rare variant of cutaneous mastocytosis. Treatment included a prolonged course of corticosteroids and antihistamines. Recognition of this rare form of mastocytosis is important, as it can be easily mistaken for other pediatric bullous diseases and is associated with life-threatening complications including vasodilation, anaphylactic shock, gastrointestinal bleeding, and death.

Diffuse cutaneous mastocytosis with novel somatic KIT mutation K509I and association with tuberous sclerosis

Diffuse cutaneous mastocytosis (DCM) is a rare but potentially fatal condition when diagnosis and targeted treatments are delayed. This case illustrates the life-threatening complications in DCM and reviews the currently available treatments. To our knowledge, this is the first report of mastocytosis with somatic K509I mutation and concomitant tuberous sclerosis.

Cutaneous mastocytosis treatment: strategies, limitations and perspectives

Mastocytosis is a rare myeloproliferative disease, characterized by excessive proliferation and accumulation of mast cells in the tissues. In cutaneous mastocytosis (CM), mast cells infiltration is limited to the skin, whereas in systemic mastocytosis (SM) internal organs are involved. The first-line treatment in CM is antimediator therapy (mainly H1 and H2 antihistamines) and short-term topical corticosteroids. Phototherapy is the second-line therapy which may be considered when antihistamines do not produce the expected improvement. New therapeutic options include omalizumab and KIT-targeting agents. Although the disappearance of skin lesions has been reported as a result of cytoreductive therapies in SM, the use of potentially toxic drugs in CM is not recommended. In all adults with mastocytosis and in pediatric patients with severe CM, a persistently elevated serum tryptase level and anaphylaxis in medical history, equipping with epinephrine autoinjector for use in case of anaphylaxis is recommended.

Pediatric Expression of Mast Cell Activation Disorders

Mast cell activation disorders is a term proposed to cover diseases and conditions related to activation of mast cells and effects of mast cell mediators. In its broadest sense, the term encompasses a wide range of diseases from allergic asthma to rhinoconjunctivitis, urticaria, food allergy, anaphylaxis, mastocytosis, and other conditions where MC activation is contributing to the pathogenesis. This article focuses on clinical presentations, challenges, and controversies in pediatric mastocytosis and gives an overview of current knowledge and areas in need of further research.

Cutaneous Mastocytosis in Adults and Children: New Classification and Prognostic Factors

The skin is one of the most frequent tissues affected in patients with mastocytosis, but cutaneous lesions are highly heterogeneous in shape, size, color, number, localization, and distribution. The World Health Organization recognizes 3 subtypes of cutaneous mastocytosis (CM): maculopapular CM (MPCM), diffuse CM, and mastocytoma of skin. An international task force of experts in mastocytosis has recently proposed subdividing MPCM into monomorphic and polymorphic, which could predict the duration of the disease in children. More research is warranted to develop an improved classification of CM that ideally should incorporate robust factors with prognostic impact on disease behavior.

Topical pimecrolimus for paediatric cutaneous mastocytosis

BACKGROUND

Most cases of paediatric cutaneous mastocytosis (CM) occur before the age of 2 years, and regression occurs in only 67% of children. Given the absence of any specific therapy, CM is usually treated symptomatically. A few publications have reported the beneficial effect of calcineurin inhibitors for CM.

AIM

We sought to evaluate the clinical effectiveness and safety profile of topical pimecrolimus cream for the treatment of CM.

METHODS

We performed a retrospective study of all diagnosed cases of CM treated with topical pimecrolimus 1% cream between 2013 and 2015. All patients were evaluated in a paediatric dermatology unit of a tertiary medical centre. Epidemiological, clinical and treatment data, including effectiveness and safety, were reviewed.

RESULTS

In total, 18 children (11 male, 7 female; age range 3-42 months) with CM were evaluated. Of the 146 treated lesions, 39 (26.7%) disappeared and 98 (67%) faded or developed postinflammatory hyperpigmentation. Of the 119 papular lesions, 24 (16.4%) showed partial flattening and 56 (47%) became macular. Darier sign became negative in 14 (82%) of 17 patients. No topical or systemic complications were observed.

CONCLUSIONS

Topical therapy with pimecrolimus 1% cream should be considered in the treatment of CM.

Natural history and treatment of cutaneous and systemic mastocytosis

INTRODUCTION

Mastocytosis, a heterogeneous group of disorders, is characterized by an abnormal increase in the number of mast cells that is limited to the skin (cutaneous mastocytosis), involving extracutaneous tissues (systemic mastocytosis), or presenting as solid tumours (mastocytoma and mast cell sarcoma). Recent studies estimate that 1 in 10,000 people are diagnosed with mastocytosis. Although prompt diagnosis and appropriate management are crucial, little is known about the natural history and currently there are no established management guidelines. We have conducted a systematic review to assess the natural history and management of different mastocytosis subtypes.

METHODS

A systematic review and meta-analysis were conducted using the PubMed and Ovid database of studies published in English and French over the last fifteen years, from January 2001 to December 2016. Keywords 'Cutaneous mastocytosis', 'Systemic mastocytosis', 'pathophysiology', 'clinical course', 'prognosis', 'drug therapy', and 'therapy' were searched. Rate of complete resolution was subjected to pooled analysis for different mastocytosis subtypes. Meta-analysis was conducted using Stata version 12.0.

RESULTS

We reviewed 634 papers, of which 5 were included in the analysis of resolution, and 138 were included in the assessment of management. Pooled estimate for rate of complete resolution varied depending on the mastocytosis subtype. In cutaneous mastocytosis, the complete resolution rate for mastocytoma was 10% per year (95% CI: 4.8%, 15.1%) while the rate for urticaria pigmentosa was 1.9% per year (95% CI: -0.5%, 4.3%). Diffuse cutaneous mastocytosis and systemic mastocytosis subtypes did not show evidence of complete resolution in the studies reviewed. Treatment of cutaneous and systemic mastocytosis is purely symptomatic with topical corticosteroids, antihistamines, omalizumab and imatinib being common choices.

CONCLUSION

Rate of resolution of mastocytosis is only shown in urticaria pigmentosa and mastocytoma. Better management guidelines are required to improve the health of these patients.

The role of serum tryptase in the diagnosis and monitoring of pediatric mastocytosis: a single-center experience

INTRODUCTION

In children, cutaneous mastocytosis (CM) is considered to be a benign disease associated with mast cell mediator-related symptoms. However, systemic mastocytosis (SM) and anaphylaxis may also occur. Since the basal serum tryptase (bsT) level reflects mast cell burden, its determination is recommended in the diagnosis and follow-up.

AIM

To compare clinical presentation and the course of mastocytosis in children with normal and clearly elevated bsT levels as well as to assess its usefulness in the diagnosis and monitoring of the course of the disease.

MATERIAL AND METHODS

A retrospective analysis of 102 medical records of children with mastocytosis diagnosed and followed-up in the Gdansk Mastocytosis Center in 2014 was performed.

RESULTS

Maculopapular CM (MPCM) was diagnosed in 91 (89.22%) children, diffuse cutaneous mastocytosis (DCM) in 7 (6.86%) and mastocytoma in 4 (3.92%). The presence of flushing and bullous lesions was more frequent in children with bsT levels > 20 ng/ml in comparison with those who had bsT ≤ 20 ng/ml (p = 0.002 and p = 0.03, respectively). Anaphylaxis occurred in 2 MPCM children with bsT levels in normal ranges. In all of the 3 children with persistently and clearly elevated bsT levels, bone marrow biopsy revealed no mast cells infiltrates corresponding to SM.

CONCLUSIONS

Although mastocytosis children with clearly elevated bsT levels frequently develop mediator-related symptoms, the occurrence of anaphylaxis in this age group may be difficult to predict. In pediatric cases with suspected SM, the bsT level is one of the crucial parameters considered before the decision on bone marrow biopsy.

Mast cell disorders: Kids are not just little people

Cutaneous mastocytosis is characterized by a pathologic increase in mast cells in the skin and may also involve extracutaneous organs. Symptoms, which are triggered by mast cell degranulation, vary depending on the burden of skin disease and the presence of extracutaneous disease. The clinical presentation, risk of systemic disease, pathogenesis, prognosis, and treatment options differ, largely depending on age at presentation. In the pediatric population, spontaneous remission is typical, generally by puberty, whereas in adults, progression is observed. Extracutaneous involvement and associated hematologic disorders seldom occur in children, as opposed to adults. It is therefore important to avoid overreliance on adult-based approaches to management of cutaneous mastocytosis in the pediatric population. We focus on differences in presentation, workup, and management of pediatric- and adult-onset cutaneous mast cell disorders.

Transient hypogammaglobulinaemia of infants in children with mastocytosis - strengthened indications for vaccinations

Mastocytosis is a disease caused by the accumulation of mast cells (MC) in the skin and/or in other tissues. Both the cutaneous form of the disease (CM) predominating in children and the systemic form (SM) typical for adults are associated with the occurrence of MC mediator-related symptoms. The release of mediators can be induced by physical stimuli and/or specific triggering factors. The routine vaccination program performed in the majority of children in infancy can be considered as an additional factor provoking exacerbation of CM. Conscious of the important role of MC in the innate immunity, we have analysed retrospective data concerning the levels of immunoglobulins, an adaptive factor, in a group of 74 infants and toddlers with CM. The values corresponding to transient hypogammaglobulinaemia of infants (THI) were found in 8 (10.81%) of cases. Classification of the antibody deficiency was done according to the working definitions for clinical diagnosis of primary immunodeficiency of the European Society of Immunodeficiencies (ESID) Registry - version May 11, 2015. Following the retrospective data, the final diagnosis of THI cannot be made due to the young age of the study group. The percentage may significantly exceed the published incidence of THI, i.e. about 0.11%. The results of our study may indicate, importantly, a higher incidence of THI in childhood-onset mastocytosis than in the general paediatric population and strengthen indications for vaccinations. In conclusion, we suggest that THI may be considered as a new aspect of paediatric mastocytosis that requires further investigation.

Current approach to cutaneous mastocytosis in childhood

Mastocytosis is a heterogeneous disorder characterized by clonal proliferation and accumulation of mast cells in one of more organs which may lead to different clinical pictures. Pathological increase and activation of mast cells in various tissues can cause different clinical pictures. Cutaneous mastocytosis limited to the skin is the most typical clinical picture observed in children and systemic mastocytosis is very rare in the pediatric age group. The diagnosis of cutaneous mastocytosis is based on clinical findings, but is often delayed due to lack of clinical awareness of the disease and lack of its consideration in the differential diagnosis. This article focuses on the current diagnosis, management and treatment of cutaneous mastocytosis in children in order to increase awareness about this issue.

Diffuse Cutaneous Bullous Mastocytosis and Disseminated Intravascular Coagulation Postvaccination: A Case Report

BACKGROUND

Diffuse cutaneous bullous mastocytosis is the most rare subtype of cutaneous mastocytosis, characterized by generalized skin infiltration with mast cells and blistering.

OBJECTIVE

To increase the awareness of the natural history and potential adverse complications of this rare cutaneous condition.

METHOD AND RESULTS

We report a case of a male diagnosed on day 7 of life with follow-up of his progression over 6 years. When he was 2.5 months old, he was admitted to hospital postvaccinations with a flare of his blistering that was complicated by disseminated intravascular coagulation and polyuric acute tubular necrosis. Blistering ceased at 3 years, but at 6 years, extensive urtication continued in response to known triggers and a suboptimal dose of mast cell membrane stabilizers and histamine-1 and -2 receptor antagonists.

CONCLUSION

This case discusses the progression of this rare condition over 6 years and highlights the importance of reaching optimal pharmacologic blockage of histamine-1 and -2 receptors and stabilization of mast cell membranes in patients persistently experiencing ongoing pruritus, urtication, and flushing symptoms.

Mastocytosis among elderly patients: A multicenter retrospective French study on 53 patients

Mastocytosis is a heterogeneous group of diseases with a young median age at diagnosis. Usually indolent and self-limited in childhood, the disease can exhibit aggressive progression in mid-adulthood. Our objectives were to describe the characteristics of the disease when diagnosed among elderly patients, for which rare data are available.The French Reference Center conducted a retrospective multicenter study on 53 patients with mastocytosis >69 years of age, to describe their clinical, biological, and genetic features.The median age of our cohort of patients was 75 years. Mastocytosis variants included were cutaneous (n = 1), indolent systemic (n = 5), aggressive systemic (n = 11), associated with a hematological non-mast cell disease (n = 34), and mast cell leukemia (n = 2). Clinical manifestations were predominantly mast cell activation symptoms (75.5%), poor performance status (50.9%), hepatosplenomegaly (50.9%), skin involvement (49.1%), osteoporosis (47.2%), and portal hypertension and ascites (26.4%). The main biological features were anemia (79.2%), thrombocytopenia (50.9%), leucopenia (20.8%), and liver enzyme abnormalities (32.1%). Of the 40 patients tested, 34 (85%), 2 (5%), and 4 (10%) exhibited the KIT D816V mutant, other KIT mutations and the wild-type form of the KIT gene, respectively. Additional sequencing detected significant genetic defects in 17 of 26 (65.3%) of the patients with associated hematological non-mast cell disease, including TET2, SRSF2, IDH2, and ASLX1 mutations. Death occurred in 19 (35.8%) patients, within a median delay of 9 months, despite the different treatment options available.Mastocytosis among elderly patients has a challenging early detection, rare skin involvement, and/or limited skin disease; it is heterogeneous and has often an aggressive presentation with nonfortuitous associated myeloid lineage malignant clones, and thus a poor overall prognosis.

Cutaneous manifestations in patients with mastocytosis: Consensus report of the European Competence Network on Mastocytosis; the American Academy of Allergy, Asthma & Immunology; and the European Academy of Allergology and Clinical Immunology

Cutaneous lesions in patients with mastocytosis are highly heterogeneous and encompass localized and disseminated forms. Although a classification and criteria for cutaneous mastocytosis (CM) have been proposed, there remains a need to better define subforms of cutaneous manifestations in patients with mastocytosis. To address this unmet need, an international task force involving experts from different organizations (including the European Competence Network on Mastocytosis; the American Academy of Allergy, Asthma & Immunology; and the European Academy of Allergology and Clinical Immunology) met several times between 2010 and 2014 to discuss the classification and criteria for diagnosis of cutaneous manifestations in patients with mastocytosis. This article provides the major outcomes of these meetings and a proposal for a revised definition and criteria. In particular, we recommend that the typical maculopapular cutaneous lesions (urticaria pigmentosa) should be subdivided into 2 variants, namely a monomorphic variant with small maculopapular lesions, which is typically seen in adult patients, and a polymorphic variant with larger lesions of variable size and shape, which is typically seen in pediatric patients. Clinical observations suggest that the monomorphic variant, if it develops in children, often persists into adulthood, whereas the polymorphic variant may resolve around puberty. This delineation might have important prognostic implications, and its implementation in diagnostic algorithms and future mastocytosis classifications is recommended. Refinements are also suggested for the diagnostic criteria of CM, removal of telangiectasia macularis eruptiva perstans from the current classification of CM, and removal of the adjunct solitary from the term solitary mastocytoma.

Transglutaminase 2 expressed in mast cells recruited into skin or bone marrow induces the development of pediatric mastocytosis

BACKGROUND

Mastocytosis is characterized by a pathological increase in mast cells in organs such as skin and bone marrow. Transglutaminase 2 (TG2) expressed in mast cells contributes to allergic diseases, but its role in mastocytosis has not been investigated. This study aimed to investigate whether TG2 contributes to pediatric mastocytosis.

METHODS

Serum, various skin tissues or bone marrow (BM) biopsy and aspirates were obtained from pediatric normal control or patients with indolent systemic mastocytosis (SM), mastocytoma, and urticaria pigmentosa (UP). Tryptase, individual cytokines, leukotriene C4 (LTC4 ), and TG2 activity in the serum were determined by enzyme-linked immunosorbent assay, mast cell population by May-Grünwald-Giemsa, CD 117 by immunofluorescence, cell surface molecules by Western blot, and colocalization of c-kit and TG2 or IL-10-expressing cells, CD25, and FOXP3 by immunohistochemistry.

RESULTS

Infiltration of CD25(+) CD117(+) CD2(-) mast cells into BM and scalp/trunk/ear dermis; expression of FcεRI, tryptase, c-kit, FOXP3, CCL2/CCR2, and vascular cell adhesion molecule-1; and colocalization of c-kit and TG2 were enhanced in patient's skin tissues or BM, particularly SM, but colocalization of c-kit and IL-10-expressing cells was decreased vs. normal tissues. Amounts of LTC4 and inflammatory cytokines, expression of tryptase or TG2 activity were increased in patient's serum, BM aspirates, or ear/scalp skin tissues, respectively, vs. normal persons, but IL-10 level was decreased.

CONCLUSION

The data suggest that mast cells, recruited in the skin and BM by CCL2/CCR, may induce the development of pediatric mastocytosis through reducing IL-10 due to upregulating TG2 activity via transcription factor nuclear factor-κB. Thus, TG2 may be used in diagnosis of pediatric mastocytosis, particularly SM.

Assessment of clinical findings, tryptase levels, and bone marrow histopathology in the management of pediatric mastocytosis

BACKGROUND

The management of children with pediatric mastocytosis poses a challenge. This is because there is limited information as to the application of clinical and laboratory findings and bone marrow histopathology as they relate to medical intervention and communication.

OBJECTIVE

We sought to examine clinical aspects of pediatric mastocytosis in relationship to serum tryptase levels and bone marrow pathology to provide practical guidance for management.

METHODS

Between 1986 and 2012, 105 children were evaluated at the National Institutes of Health. Organomegaly was confirmed by means of ultrasound. Baseline tryptase levels and at least 1 subsequent tryptase measurement was available in 84 and 37 of these children, respectively. Fifty-three children underwent a bone marrow examination. These data were used to examine relationships between clinical findings, tryptase levels, and marrow histopathology.

RESULTS

In patients with high tryptase levels and severe mediator symptoms, all with organomegaly had systemic disease, and none without organomegaly had systemic disease. Serum tryptase levels differed significantly between patients with urticaria pigmentosa and those with diffuse cutaneous (P < .0001) and systemic mastocytosis (P < .0001) and in all 3 categories versus control subjects (P < .0001). Tryptase levels and symptoms decreased over time in most patients, and tryptase levels correlated with bone marrow mast cell burden in patients with systemic mastocytosis (P < .0001). There was a significant relationship between clinical resolution and the percentage decrease in tryptase levels (P = .0014).

CONCLUSIONS

The majority of children experienced major or complete disease resolution (57%), whereas the remainder exhibited partial improvement. Organomegaly was a strong indicator of systemic disease. Serum tryptase levels furthered classification and reflected clinicopathologic findings, while sequential tryptase measurements were useful in supplementing clinical judgment as to disease course.

Cutaneous Mastocytosis with Persistent Blistering: Successful Treatment with Methylprednisolone and 3-Year Follow-Up Management

Background

Mastocytosis is a rare disorder with diverse clinical manifestations. In cutaneous mastocytosis the mast cell infiltration is limited to the skin, but is often associated with systemic symptoms due to the release of mast cell mediators.

Case Report

We report a 6-month-old male infant who had skin lesions of various morphologies (macules, papules, plaques, and nodules) and sizes, persistent blistering and frequent flushing episodes for half a year. Vital signs and physical examinations were unremarkable. No abnormalities in the laboratory tests were found except for a serum tryptase level (STL) of 11.8 ng/ml. The histological and immunohistochemical examinations confirmed the diagnosis of cutaneous mastocytosis. The patient was first treated with methylprednisolone, oral levocetirizine, and topical fusidic acid/betamethasone cream. Subsequently the treatment was tapered and stopped within 9 weeks. The child’s symptoms improved and were successfully controlled with intermittent courses of ketotifen and topical hydrocortisone over 3 years.

Conclusion

Childhood cutaneous mastocytosis usually has a favorable prognosis, but in some cases the disease can progress with skin manifestations necessitating a more active systemic and topical treatment.

Electronic supplementary material

The online version of this article (doi:10.1007/s13555-015-0073-6) contains supplementary material, which is available to authorized users.

The care pathway for children with urticaria, angioedema, mastocytosis

Cutaneous involvement characterized by urticarial lesions with or without angioedema and itch is commonly observed in routine medical practice. The clinical approach may still remain complex in real life, because several diseases may display similar cutaneous manifestations. Urticaria is a common disease, characterized by the sudden appearance of wheals, with/without angioedema. The term Chronic Urticaria (CU) encompasses a group of conditions with different underlying causes and different mechanisms, but sharing the clinical picture of recurring wheals and/or angioedema for at least 6 weeks. Hereditary Angioedema (HAE) is a rare disorder characterized by recurrent episodes of non-pruritic, non-pitting, subcutaneous or submucosal edema affecting the extremities, face, throat, trunk, genitalia, or bowel, that are referred as “attacks”. HAE is an autosomal dominant disease caused by a deficiency of functional C1 inhibitor, due to a mutation in C1-INH gene (serping 1 gene) characterized by the clonal proliferation of mast cells, leading to their accumulation, and possibly mediator release, in one or more organs. In childhood there are two main forms of mastocytosis, the Systemic and the Cutaneous. The clinical features of skin lesions in urticaria, angioedema and mastocytosis may differ depending on the aetiologic factors, and the underlying pathophysiological mechanisms. The diagnostic process, as stepwise approach in routine clinical practice, is here reviewed for CU, HAE and mastocytosis, resulting in an integrated method for improved management of these cutaneous diseases. Taking into account that usually these conditions have also a relevant impact on the quality of life of children, affecting social activities and behavior, the availability of care pathways could be helpful in disentangle the diagnostic issue achieving the most cost-effective ratio.