Immunophenotype of pediatric-onset mastocytosis does not correlate with clinical course.

BACKGROUND: Pediatric mastocytosis differs from adult mastocytosis in its presentation and clinical course. However, the data regarding the immunophenotypic characterization of mast cells in children are limited. Our objective was to evaluate the immunophenotype of mast cells in pediatric mastocytosis and correlate it with the clinical course. METHODS: Biopsy specimens of children with cutaneous mastocytosis were retrieved from the institutions of pathology and were stained for CD25, CD2, and CD30. The percentage of mast cells and the staining intensity were correlated with the clinical data. RESULTS: Twenty-five biopsy specimens were included in the study. Patients' average age was 15.4 at presentation and 37.5 months at biopsy performance. Clinical presentations included maculopapular cutaneous mastocytosis in 79% and mastocytoma in 21% of cases. CD25, CD2, and CD30 were positive in 60%, 44%, and 84% of the biopsy specimens, respectively. The staining score was significantly higher for CD30 as compared to those for CD25 and CD2 (P = 0.02). No correlation was found between the immunophenotype and the clinical form or course of disease. CONCLUSIONS: Our results confirm that CD30 is a sensitive marker for pediatric-onset mastocytosis. Nevertheless, its expression does not correlate with clinical subtype or clinical course. The sensitivity of CD25 is higher than that of CD2 in skin lesions.

Higher prevalence of vertebral fractures in systemic mastocytosis, but not in cutaneous mastocytosis and idiopathic mast cell activation syndrome.

Little is known about osteoporosis in mast cell disorders (MCDs) not related to systemic mastocytosis. We described osteoporosis and fractures in MCDs and showed that systemic mastocytosis was the only studied MCDs associated with osteoporotic vertebral fractures. INTRODUCTION: To describe osteoporosis (OP) and fragility fractures in mast cell disorders (MCDs). METHODS: We retrospectively analyzed data concerning all successive patients with systemic mastocytosis (SM), cutaneous mastocytosis (CM), and mast cell activation syndromes (MCAS) diagnosed in our mastocytosis expert center between 2004 and 2015. We collected data concerning demographic profiles, clinical signs of MCD, osteoporosis, fractures, densitometry, and biological assessment of MCD. We compared CM and MCAS patients with SM patients with regard to the characteristics of OP and fragility fractures. RESULTS: We assessed 89 SM patients, 20 CM patients, and 20 MCAS patients. Osteoporosis was less frequent in CM (15.0%) and MCAS (10.0%) than in SM (44.9%). Similarly, fractures were less frequent in non-SM MCDs, respectively 5.0%, 5.0%, and 28.1%. SM patients displayed high prevalence of vertebral fractures (22.5%), mostly multiple. Conversely, in non-SM patients, vertebral fractures appeared to be uncommon (5%) and more frequently associated with risk factors for osteoporosis. CONCLUSIONS: SM is associated with multiple vertebral osteoporotic fractures, whereas CM and MCAS do not appear to be associated with this phenotype.

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.

Mastocytosis.

Mastocytosis is a rare disease caused by excessive production of mast cells. Clinical presentation is variable, often based on the type of mastocytosis, but in all types of mastocytosis there seems to be an increase in the risk of anaphylaxis. Systemic mastocytosis is diagnosed based on bone marrow biopsy. Treatment is variable based on the type of mastocytosis, but trigger avoidance and anaphylaxis treatment are mainstays. There are no therapies that change the natural course of mastocytosis. For cutaneous mastocytosis, treatment is conservative and aimed at symptom relief.

Mastocytosis: a comprehensive insight.

Mastocytosis refers to a heterogeneous group of clinical disorders characterized by an abnormal accumulation of mast cells (MCs) in various tissues. The skin is the organ most frequently involved, but all organs may be affected. The clinical signs and symptoms are produced by the functional effects of mast cell-derived mediators and the anatomical distribution of the mast cells. The 2008 WHO-classification defines 7 categories of mastocytosis. Skin disease, with or without systemic involvement, is by far the most common form of childhood mastocytosis. Measurement of serum tryptase is important in the diagnostic algorithm of pediatric mastocytosis. In children with tryptase <20 ng/mL, the diagnosis of cutaneous mastocytosis (CM) may be decided upon without bone marrow examination (BME), unless other signs of SM are present. If the baseline tryptase level exceeds 100 ng/mL, a BME should be considered regardless of age. If the serum tryptase is 20-100 ng/mL in children without other signs of SM, the provisional diagnosis "mastocytosis in the skin" (MIS) can be established and monitored until puberty. If MIS remains present after puberty, a BME should be performed. In adult-onset mastocytosis a complete staging and application of the systemic mastocytosis criteria should always be performed. Treatment is mainly directed at alleviation of symptoms. As c-kit mutations prove to be very important in the pathogenesis of mastocytosis, targeted therapies using kit inhibitors may evolve as important future therapeutic options.

Actualización en mastocitosis. Parte 1: fisiopatología, clínica y diagnóstico / Update on Mastocytosis (Part 1): Pathophysiology, Clinical Features, and Diagnosis

Las mastocitosis constituyen un grupo heterogéneo de enfermedades caracterizadas por la proliferación clonal de mastocitos en distintos órganos, siendo la localización cutánea la más frecuente. Es «una enfermedad rara o poco frecuente», y afecta a todos los grupos de edad, si bien suele aparecer en la primera década de la vida o entre la segunda y la quinta década de la vida, con una distribución similar por sexos. En los últimos años se han realizado grandes avances en el conocimiento fisiopatogénico del trastorno: las mutaciones somáticas del gen c-kit y la presencia de alteraciones inmunofenotípicas en los mastocitos son elementos importantes en la fisiopatogenia de las mastocitosis. Las manifestaciones clínicas son variadas y las lesiones cutáneas son la clave diagnóstica en la mayoría de los pacientes

Mastocytosis is a term used to describe a heterogeneous group of disorders characterized by clonal proliferation of mast cells in various organs. The organ most often affected is the skin. Mastocytosis is a relatively rare disorder that affects both sexes equally. It can occur at any age, although it tends to appear in the first decade of life, or later, between the second and fifth decades. Our understanding of the pathophysiology of mastocytosis has improved greatly in recent years, with the discovery that somatic c-kit mutations and aberrant immunophenotypic features have an important role. The clinical manifestations of mastocytosis are diverse, and skin lesions are the key to diagnosis in most patient

Absence of circulating mast cell precursors in paediatric mastocytosis: could it reflect a different pathophysiology between adults and children with mastocytosis?

BACKGROUND: Mastocytosis is a heterogeneous disease whose different subtypes also vary in aggressivity. Children typically present with cutaneous mastocytosis. We identified, in our previous work, a peripheral CD34-c-Kit+mast cell precursor by flow cytometry in systemic forms but not in cutaneous forms of adult mastocytosis. OBJECTIVES: We wanted to know if such a mast cell precursor exists among children with mastocytosis. METHODS: We analysed 10 children with mastocytosis for c-Kit+CD34- mast cell precursors by flow cytometry. RESULTS: In contrast to adults with mastocytosis, we did not detect any circulating mast cell precursors by flow cytometry in the peripheral blood of children with mastocytosis. CONCLUSION: The clinical symptoms observed among children with cutaneous mastocytosis could be induced by cutaneous mast cell mediators and not by circulating mast cells. These results may help to better understand the differences between adult and childhood mastocytosis.

Pimecrolimus induces apoptosis of mast cells in a murine model of cutaneous mastocytosis.

BACKGROUND: Cutaneous mastocytosis (CM) is a common type of mastocytosis. Current treatment of CM is generally symptomatic. Pimecrolimus has been demonstrated as an effective anti-inflammatory drug for the treatment of inflammatory skin diseases, but whether it treats CM remains unknown. METHODS: The murine model of CM was induced by subcutaneous injection of 100 µg/kg recombinant murine stem cell factor (rmSCF) for a total of 17 days in Balb/c mice. Beginning on the 8th day, treatment with pimecrolimus 1% cream or vehicle was performed topically and daily for 10 days. The clinical signs of CM were scored, and pathological analysis was performed with toluidine blue staining and hematoxylin and eosin staining. The in situ apoptotic mast cells (MCs) were studied by terminal deoxynucleotidyl transferase-mediated dUTP nick-end labeling assay. The cutaneous histamine level was measured by ELISA. RESULTS: In the rmSCF-treated mice, the clinical signs of CM, including erythema, wheal after rubbing lesion skins, and increased thickness of skin, were obvious compared to control mice, and were reduced after pimecrolimus treatment. The numbers of cutaneous MCs and neutrophils were significantly greater in mice with CM than in control mice, and pimecrolimus treatment decreased the numbers of MCs but not neutrophils. Extensive apoptosis of cutaneous MCs was observed in pimecrolimus-treated mice. The cutaneous histamine level was elevated in the mice with CM compared with healthy controls, and was lowered after treatment with pimecrolimus. CONCLUSIONS: Pimecrolimus effectively treats CM by reducing the density of cutaneous MCs and the subsequent histamine production through inducing MCs apoptosis.

Mastocitosis en edad pediátrica / Mastocytosis in children

Las mastocitosis incluyen un amplio espectro de patologías que tienen en común la infiltración anormal de mastocitos en diversos órganos, siendo la piel el más frecuentemente comprometido. Se reconocen dos variantes principales de la enfermedad: la mastocitosis cutánea (MC), que sólo compromete la piel, y la mastocítosis sistémica (M S), donde hay compromiso de órganos extracutáneos. La sintomatología de ambas variantes es causada por la infiltración celular y daño directo sobre los tejidos, así como por la liberación de mediadores químicos a la circulación sistémica, lo que hace que su presentación clínica sea altamente variable. Las mastocitosis en niños se presentan generalmente como MC, son de buen pronóstico y evolucionan con remisión de las lesiones en la mayoría de los casos. Las MS son muy poco frecuentes en este grupo etario; sin embargo, su curso crónico y la agresividad que pueden adquirir ponen en relieve la importancia de considerarlas en el diagnóstico diferencial de estos cuadros. En la actualidad no existe tratamiento curativo para las mastocitosis y el manejo es fundamentalmente sintomático.

Mastocytosis is a heterogeneous group of diseases characterized by the abnormal infiltration of mast cells (MCs) in one or more organ systems, being the skin the most common organ affected. Two main variants of the disease are recognized: cutaneous mastocytosis (CM), if abnormal infiltrates are confined to the skin, and systemic mastocytosis (SM) , if extra-cutaneous tissues are involved. Symptoms are extremely variable and result from MC-derived mediators and from destructive infiltration of MCs. The typical presentation of pediatric-onset mastocytosis consists of cutaneous manifestations, and usually regresses spontaneously. SM is a chronic disease with variable clinical course ranging from asymptomatic to highly aggressive and rapidly devastating. SM is rare in children but should be considered in the differential diagnosis. No curative treatment has been yet reported for mastocytosis and only symptomatic therapy is available.

[Mastocytosis. A challenge in anaesthesiology]. / Mastozytose. Herausforderung in der Anästhesie.

Mastocytosis is a general term for a heterogeneous group of rare disorders. Many agents used in anaesthesia can trigger mast cell degranulation with release of histamine, prostaglandin, tryptase and heparin. Therefore, patients with mastocytosis are high-risk patients when undergoing anaesthesia. The management of these patients in anaesthesia will be discussed on the basis of the literature and illustrated with the discussion of three case reports. A premedication with antihistamines and a glucocorticoid is recommended. For induction of general anaesthesia propofol, etomidate, ketamine, a fentanyl-type opioid, cis-atracurium or pancuronium are recommended. Anaesthesia can be maintained either by a total intravenous technique or with a volatile anaesthetic such as sevoflurane.

Exploring the mast cell enigma: a personal reflection of what remains to be done.

Mast cells are traditionally viewed as effector cells of allergic reactions and parasitic diseases, but their importance in host defense against bacteria, in tissue remodelling, their bone marrow and stem cell origin and a central role of the stem cell factor (SCF) as mast cell growth and chemotactic factor has been worked out only in recent years. Despite this, major aspects about the nature of the cells and their role in disease remain unclear. This holds in particular for the identification of mast cell precursors and the role of growth factors that stimulate specific mast cell commitment from stem cells, such as nerve growth factor, neutrotrophin-3 and certain interleukins, alone and during interaction with SCF. Early data suggesting also an involvement of specific transcription factors need to be expanded in this process. Furthermore, although mast cell proliferative disease (mastocytosis) has been shown to be often associated with SCF receptor c-kit mutations, reasons for the development of this disease remain unclear. This holds also for mast cell release mechanisms in many types of mast cell-dependent urticaria. Exciting new insights are emerging regarding the role of mast cells in bacterial infections, in defense against tumors, in wound healing and in the interplay with the nervous system, with hormones, and in the neurohormonal network. The aim of this reflection is to delineate the many known and unknown aspects of mast cells, with a special focus on their development, and to discuss in detail two mast cell-related diseases, namely mastocytosis and urticaria.

Anaphylaxis in patients with mastocytosis: a study on history, clinical features and risk factors in 120 patients.

BACKGROUND: Excessive mast cell mediator release may lead to anaphylaxis in patients with mastocytosis. However, the incidence, clinical features and trigger factors have not yet been analyzed. METHODS: To identify risk factors for anaphylaxis in mastocytosis, we determined cumulative incidence, severity, clinical characteristics, and trigger factors for anaphylaxis in 120 consecutive patients (53 male; 67 female, median age and range 24 years, 1 month to 73 years), and correlated these with disease severity of mastocytosis, skin involvement, basal total serum tryptase, and diaminooxidase concentrations. RESULTS: The cumulative incidence of anaphylaxis in patients with mastocytosis was higher in adults (49%; P < 0.01) compared with that in children (9%). Only children with extensive skin involvement had experienced anaphylaxis. In adults, anaphylaxis was correlated to the absence of urticaria pigmentosa lesions (P < 0.03). Reactions occurred more frequently in adults with systemic (56%) when compared with cutaneous mastocytosis (13%; P < 0.02). In adults, 48% of reactions were severe, and 38% resulted in unconsciousness. Major perceived trigger factors for adults were hymenoptera stings (19%), foods (16%), and medication (9%); however, in 26% of reactions, only a combination of different triggers preceded anaphylaxis. Trigger factors remained unidentified in 67% of reactions in children compared with 13% in adults. Patients with anaphylaxis had higher basal tryptase values (60.2 +/- 55 ng/ml, P < 0.0001) in comparison with those without (21.2 +/- 33 ng/ml), but not diaminooxidase levels. CONCLUSION: Adult patients and children with extensive skin disease with mastocytosis have an increased risk to develop severe anaphylaxis; thus, an emergency set of medication including epinephrine is recommended.

Mastocytosis in children: clinicopathological study based on 35 cases.

Immunohistochemical staining is useful in the diagnosis of bone marrow infiltration in systemic mastocytosis. However, it is not clear if antibody staining may be helpful in the diagnosis of cutaneous mastocytosis (CM). We studied the histological appearance of CM in 35 pediatric patients. Cases were assigned to three basic clinical groups: I--Urticaria pigmentosa (UP, n=29); II--Mastocytomas (n=4); and III--Diffuse Cutaneous Mastocytosis (DCM, n=2). The analysis of clinical information revealed an association between the presence of diarrhea and a higher number of cells/field. Nine doubtful cases, all of them macules, were selected based on the scarcity of mast cells (MC) and the absence or rarity of other inflammatory cells. We compared the number of cells identified in Giemsa and immunohistochemical stains in definite and doubtful cases. The intraclass correlation statistic tested the concordance between each staining method. All 9 dubious cases according to the Giemsa stain had their CM diagnosis confirmed by the immunohistochemistry analysis. The intraclass correlation between Giemsa and c-kit was good (0.7) when the number of MC was high. However, there was no correlation between the mast cells counts in the two different stains in the dubious cases. The immunohistochemistry with c-kit might make CM diagnosis easier, especially in the macular cases, when there is a lower number of MC.

Cutaneous mastocytosis: demographic aspects and clinical features of 55 patients.

BACKGROUND: Mastocytosis is a rare, heterogeneous group of disorder with abnormal increase of mast cells in one or more organ systems. OBJECTIVE: To evaluate the demographic and clinical features of cutaneous mastocytosis (CM). METHODS: Records of 55 patients with cutaneous mastocytosis were retrospectively analysed. RESULTS: Of the 22 females and 33 males, 80% had urticaria pigmentosa/maculopapular CM and 20% had mastocytoma. Of all cases, 81.8% had first lesions in childhood. The most common presentation was involvement of trunk together with extremities. Thirteen (23.6%) patients had history of bulla; Darier's sign was positive in 34 of 38 patients. Itching was the most common complaint, provocated by hot weather/bath. CONCLUSION: Clinical presentations of urticaria pigmentosa/maculopapular CM and mastocytoma are similar regarding gender, age of onset, age of diagnosis, and presence of Darier's sign and history of bulla. In contrast to mastocytoma, urticaria pigmentosa/maculopapular CM lesions were frequently located on trunk together with extremities.

[Cutaneous mastocytosis]. / Mastocytose cutanée.

Cutaneous mastocytosis represent the most frequent form of mastocytosis, rare diseases, defined by an abnormal accumulation and proliferation of mastocytes in one or more organs. Cutaneous mastocytosis more often appear early in childhood and usually resolve spontaneously by the time of puberty. In adult, cutaneous mastocytosis rarely involute and are frequently associated to extracutaneous involvement and so, are in fact systemic mastocytosis. Clinical presentation of cutaneous mastocytosis includes polymorphous cutaneous lesions linked to mastocytes skin infiltration often associated to acute episodes (lesional or systemic flush) due to mast cells degranulation. The cause of mastocytosis is unknown. Several mutations of the c-kit proto-oncogen coding for the transmembrane receptor kit of the stem groth factor, factor of maturation, proliferation and activation of mastocytes, are often observed. Currently, the treatment of cutaneous mastocytosis is mainly symptomatic.