Mastocytosis in the skin in dogs: A multicentric case series

Canine cutaneous mastocytosis (CM) is rare in contrast to canine mast cell tumours. In humans, CM commonly affects children and is usually indolent with possible spontaneous resolution. Systemic mastocytosis (SM) with bone marrow involvement typically affects adults, can have a poor outcome, and often includes skin lesions. 'Mastocytosis in the skin' (MIS) is the preferred term of skin lesions, if bone marrow evaluations are not available, which is often the cases in dogs. In human SM and CM, KIT mutations are often detected. The veterinary literature suggests clinical resemblances between human and canine MIS, but data is limited, and KIT mutations are rarely assessed. This retrospective study describes clinicopathological findings, treatment and outcome of 11 dogs with suspected MIS. Dogs with multiple mast cell tumours were excluded. Histopathology reports (n = 5) or slides (n = 6) were reviewed. KIT mutation analysis including exons 8, 9, 11, 14 and 17 were analysed in eight dogs. Median age at diagnosis was 4 years (range, 1-12). Typical clinical signs included multifocal to generalised nodules and papules. Histologically, skin lesions were characterised by dermal infiltration of well-differentiated mast cells. KIT mutations were detected in 3/8 dogs (exon 9: n = 2; exon 11: n = 1). One dog had mastocytaemia suggesting possible SM. Glucocorticoids were mostly successful with lesion improvement in all treated dogs (n = 8). This cohort highlights resemblances between human and canine MIS. Further studies are required to confirm these findings and establish diagnostic criteria for CM and MIS associated with SM in dogs.

Telangiectasia Macularis Eruptiva Perstans in a 55-Year-Old Female With Type 2 Diabetes Mellitus

The authors would like to report a rare case of telangiectasia macularis eruptiva perstans (TMEP), a form of cutaneous mastocytosis, in a 55-year-old female patient with a recent diagnosis of type 2 diabetes mellitus on empagliflozin. The patient presented with a two-month history of rash and itching on her lower extremities, unresponsive to topical treatment. A dermoscopic evaluation and a skin biopsy confirmed the diagnosis of TMEP. The patient demonstrated significant improvement with antihistamine and topical steroid treatment.

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.

Urticaria pigmentosa and systemic mastocytosis

Key Clinical Message

Additional investigations for systemic involvement should be initiated once the diagnosis of cutaneous mastocytosis has been established in an adult patient. A serum tryptase can serve as a screening test for systemic mastocytosis, and persistent elevations should prompt further investigations, such as bone marrow studies.

Abstract

Urticaria pigmentosa (UP) is the most common form of cutaneous mastocytosis, presenting as a wide variety of macroscopic appearances. Cutaneous mastocytosis in pediatric patients usually does not present with systemic involvement, but more than half of adult patients with cutaneous mastocytosis demonstrate systemic involvement. Currently, there is no guidance surrounding systemic testing in patients with UP. A 50-year-old Caucasian male was referred to the Clinical Immunology and Allergy clinic with a history of a rash. He initially presented to hospital 12 years prior with group A beta hemolytic streptococcus bacteremia treated with multiple different antibiotics. One week following discharge, he developed erythematous brown spots on his right leg which were flat, non-pruritic, and not painful. The rash later expanded to his trunk and extremities. A skin biopsy performed 2 years prior to referral to our clinic demonstrated urticaria pigmentosa. The CD117 immunohistochemical stain showed increased perivascular and interstitial mast cells in the superficial dermis. Darier's sign was negative on physical examination, and venom testing was also negative. Although he had no symptoms of systemic involvement, his serum tryptase was elevated at 47.6 ng/mL in the context of normal kidney and liver function. A skeletal survey was normal, and an abdominal ultrasound ruled out splenomegaly. Bone marrow biopsy demonstrated a mild increase in paratrabecular and perivascular atypical mast cells, in keeping with systemic mastocytosis. Adult patients with cutaneous mastocytosis have a high likelihood of having an underlying systemic mast cell disorder. Therefore, any patient presenting with characteristic skin findings should be investigated as having a cutaneous manifestation of systemic mastocytosis. This case demonstrates the utility of serum tryptase and its role in triggering additional investigations and guiding appropriate therapy.

Urticaria and mimickers of urticaria

Urticaria is a common skin condition encountered across various specialties in medicine, especially in dermatology and allergy/immunology practice. It has a heterogeneous presentation hence it is unsurprising that many skin conditions may be confused with urticaria. Urticaria may present as acute or chronic urticaria, the latter can be further categorised into chronic spontaneous and chronic inducible. In this article, we explore, explain, and summarise various skin lesions that are considered mimickers of urticaria, to promote understanding of each of the conditions highlighted, improve recognition, and reduce misdiagnosis.

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.

Childhood Cutaneous Mastocytosis: Revisited

Cutaneous mastocytosis is a neoplasm characterized by the proliferation and accumulation of mast cells in the skin. There can be involvement of other organ systems as well. Cutaneous manifestations can vary from mastocytoma to maculopapular lesions to diffuse cutaneous form. There can be symptoms associated with mast cell mediators release like itching, flushing, hypotension, diarrhoea, abdominal pain, and anaphylaxis. Hence, the mainstay of treatment is avoidance of triggers causing these mediators to release, anti-histamines, topical/intra-lesional/systemic steroids, mast cell-targeted therapy, epinephrine, and omalizumab depending upon the severity of symptoms/signs. Childhood cases usually have a good prognosis except in a few cases, especially those with systemic involvement. Such situations might warrant cytoreductive therapy, polychemotherapy, or autologous stem cell transplantation. Here, we intend to review the English literature on childhood cutaneous mastocytosis.

A Case of Systemic Mastocytosis Diagnosed Endoscopically

Mastocytosis, or mast cell proliferation, is very rare. Overall, 60% of patients with systemic mastocytosis (SM) have gastrointestinal involvement, with the colon being the most prevalent affected site. Most patients are diagnosed by bone marrow biopsy. Although gastrointestinal symptoms are common, patients are rarely diagnosed via endoscopy. Indolent SM, which is characterized by both gastrointestinal and cutaneous symptoms in the absence of bone marrow suppression, is extremely rare and often missed due to the complexity of the diagnosis. Here, we present the case of a patient with abdominal pain, flushing, and nausea who was diagnosed endoscopically with SM, likely the indolent type.

Persistent Facial Flushing in a Patient with Telangiectasia Macularis Eruptiva Perstans: An Unusual but Should Emphasized Clinical Finding

Facial flushing is one of the common conditions in dermatology, which affects the aesthetic of patients to a great extent, and even leads to psychological and economic burdens. The most common causes of facial flushing are often inflammatory skin diseases such as rosacea, contact dermatitis, and others, but the facial flushing as a sign can also be the cutaneous manifestation of systemic disease. Telangiectasia macularis eruptiva perstans (TMEP) is a rare disease associated with mast cells. Here, we describe an unusual clinical finding with persistent facial flushing in a patient with TMEP.

Mastocytosis: Fertility and Pregnancy Management in a Rare Disease

Mastocytosis encompasses a subset of rare diseases, characterized by the presence and accumulation of abnormal neoplastic MC in various organ systems, including skin, bone marrow, spleen and gastrointestinal tract. Clinical manifestations are highly heterogeneous, as they result from both MC mediator release and MC organ infiltration. Both pregnancy, a lifetime dominated by huge physiological changes, and labor can provide triggers that could induce worsening of mastocytosis symptoms. On the other hand, mastocytosis has relevant implications in obstetric management and prenatal care during all the pregnancy. In this review article, current knowledge about the impact of mastocytosis on fertility and pregnancy outcome will be reviewed and discussed, with the aim to provide clinical practice guidance for the evaluation and management of pregnancy and delivery in patients with cutaneous and systemic mastocytosis.

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.

Mastocytosis-A Review of Disease Spectrum with Imaging Correlation

Simple Summary

In this review will discuss the clinical presentation, pathophysiology, and role of imaging in detection and extent estimation of the systemic involvement of the disease, in addition to demonstration of appearance on varying imaging modalities. Familiarity with the potential imaging findings associated with mastocytosis can aid in early disease diagnosis and classification and accordingly can lead directing further work up and better management.

Abstract

Mastocytosis is a rare disorder due to the abnormal proliferation of clonal mast cells. Mast cells exist in most tissues, mature in situ from hematopoietic stem cells and develop unique characteristics of local effector cells. Mastocytosis develops by activation mutation of the KIT surface receptor which is involved in the proliferation of a number of cell lines such as mast cells, germ cells, melanocytes, and hematopoietic cells. It manifests as two main categories: cutaneous mastocytosis and systemic mastocytosis. Imaging can play an important role in detection and characterization of the disease manifestation, not only by radiography and bone scans, but also magnetic resonance imaging and computed tomography, which can be more sensitive in the assessment of distinctive disease patterns. Radiologists should be aware of various appearances of this disease to better facilitate diagnosis and patient management. Accordingly, this review will discuss the clinical presentation, pathophysiology, and role of imaging in detection and extent estimation of the systemic involvement of the disease, in addition to demonstration of appearance on varying imaging modalities. Familiarity with the potential imaging findings associated with mastocytosis can aid in early disease diagnosis and classification and accordingly can lead directing further work up and better management.

Anaphylaxis and epinephrine autoinjector use in pediatric patients with cutaneous mastocytosis

BACKGROUND/OBJECTIVES

Mastocytosis is a complex disorder presenting with a broad clinical spectrum. In this study, we aimed to evaluate the frequency of systemic symptoms, necessity of the usage of epinephrine autoinjectors (EAI), and factors affecting the use of EAI among pediatric patients with cutaneous mastocytosis (CM).

METHODS

The study population was composed of 53 patients with CM. The clinical data were collected from the medical files. A questionnaire about the patient's anaphylaxis experiences and treatment attitudes toward EAI was performed.

RESULTS

Thirty-three of 53 patients were male (62.3%), and the median age of the study participants was 80 months. Anaphylaxis was reported in two patients (3.7%). One of the patients had drug-induced anaphylaxis, and the other had venom-induced anaphylaxis. Three patients (5.6%) reported a personal history of EAI use due to systemic symptoms. Patients with higher serum tryptase level and cases of familial mastocytosis had more systemic symptoms (P = .012 and P = .010, respectively). The patient rate of compliance with EAI for prescription filling and carrying the EAI was 88.7% and 79.2% respectively. 41.5% of parents were hesitant to use EAI when necessary, although they were trained for the use of it by medical staff.

CONCLUSIONS

The rate of anaphylaxis in patients with CM in the current study wassignificant and justifies prescribing EAI. Detailed education and counseling on EAI usage are needed to reduce parental hesitancy.

Developing a standardized approach for assessing mast cells and eosinophils on tissue biopsies: A Work Group Report of the AAAAI Allergic Skin Diseases Committee

Mast cells and eosinophils are commonly found, expectedly or unexpectedly, in human tissue biopsies. Although the clinical significance of their presence, absence, quantity, and quality continues to be investigated in homeostasis and disease, there are currently gaps in knowledge related to what constitutes quantitatively relevant increases in mast cell and eosinophil number in tissue specimens for several clinical conditions. Diagnostically relevant thresholds of mast cell and eosinophil numbers have been proposed and generally accepted by the medical community for a few conditions, such as systemic mastocytosis and eosinophilic esophagitis. However, for other mast cell- and eosinophil-associated disorders, broad discrepancies remain regarding diagnostic thresholds and how samples are processed, routinely and/or specially stained, and interpreted and/or reported by pathologists. These discrepancies can obfuscate or delay a patient's correct diagnosis. Therefore, a work group was assembled to review the literature and develop a standardized consensus for assessing the presence of mast cells and eosinophils for a spectrum of clinical conditions, including systemic mastocytosis and cutaneous mastocytosis, mast cell activation syndrome, eosinophilic esophagitis, eosinophilic gastritis/enteritis, and hypereosinophilia/hypereosinophilic syndrome. The intent of this work group is to build a consensus among pathology, allergy, dermatology, hematology/oncology, and gastroenterology stakeholders for qualitatively and quantitatively assessing mast cells and eosinophils in skin, gastrointestinal, and bone marrow pathologic specimens for the benefit of clinical practice and patients.

Case Report and Review of the Literature: Bullous Skin Eruption After the Booster-Dose of Influenza Vaccine in a Pediatric Patient With Polymorphic Maculopapular Cutaneous Mastocytosis

Vaccination is a well-known trigger for mast cell degranulation in subjects affected by mastocytosis. Nevertheless, there is no exact standardized protocol to prevent a possible reaction after a vaccine injection, especially for patients who have already presented a previous vaccine-related adverse event, considering that these patients frequently tolerate future vaccine doses. For this reason, we aim to share our experience at Meyer Children's University Hospital in Florence to raise awareness on the potential risk for future vaccinations and to discuss the valuable therapeutic strategies intended to prevent them, taking into account what is proposed by experts in literature. We describe the case of an 18-month-old female affected by a polymorphic variant of maculopapular cutaneous mastocytosis that presented an extensive bullous cutaneous reaction 24 hours after the second dose (booster dose) of inactivated-tetravalent influenza vaccine, treated with a single dose of oral corticosteroid therapy with betamethasone (0.1 mg/kg) and an oral antihistamine therapy with oxatomide (1 mg/kg/daily) for a week, until resolution. To the best of our knowledge, in the literature, no documented case of reaction to influenza vaccine in maculopapular cutaneous mastocytosis is described. Subsequently, the patient started a background therapy with ketotifen daily (0.05 mg/kg twice daily), a non-competitive H1-antihistamine, and a mast cell stabilizer (dual activity). A non-standardized pharmacological premedication protocol with an H1-receptor antagonist (oxatomide, 0.5 mg/kg) administered 12 hours before the immunizations, and a single dose of betamethasone (0.05 mg/kg) together with another dose of oxatomide (0.5 mg/kg) administered 2 hours before the injections was followed to make it possible for the patient to continue with the scheduled vaccinations. Indeed, no reactions were subsequently reported. Thus, in our experience, a background therapy with ketotifen associated with a premedication protocol made by two doses of oxatomide and a single dose of betamethasone was helpful to make possible the execution of the other vaccines. We suggest how in these children, it could be considered the idea of taking precaution when vaccination is planned, regardless of the kind of vaccine and if a dose of the same vaccine was previously received. However, international consensus needs to be reached to manage vaccinations in children with mastocytosis and previous adverse reactions to vaccines.

Cutaneous Mastocytosis in Childhood-Update from the Literature

Mastocytosis (M) represents a systemic pathology characterized by increased accumulation and clonal proliferation of mast cells in the skin and/or different organs. Broadly, M is classified into two categories: Cutaneous mastocytosis (CM) and systemic mastocytosis (SM). In children, CM is the most frequent form. Unfortunately, pathogenesis is still unclear. It is thought that genetic factors are involved, but further studies are necessary. As for features of CM, the lesions differ in clinical forms. The most important fact is evaluating a pediatric patient with CM. It must comprise laboratory exams (with baseline dosing of total serum tryptase), a skin biopsy (with a pathological exam and, if the diagnosis is unclear, immunohistochemical tests), and a complete clinical evaluation. It is also defining to distinguish between CM and other diseases with cutaneous involvement. As for the management of CM in children, the first intervention implies eliminating trigger factors. The available cures are oral H1 and/or H2 antihistamines, oral cromolyn sodium, oral methoxypsoralen therapy with long-wave psoralen plus ultraviolet A radiation, potent dermatocorticoid, and calcineurin inhibitors. In children, the prognosis of CM is excellent, especially if the disease's onset is in the first or second years of life.

Mastocytosis in the skin accompanied by pseudo-Kaposi's sarcoma

Mastocytosis is a heterogeneous group of diseases characterized by abnormal proliferation of neoplastic mast cells in the skin and/or other extracutaneous tissues. Most patients with skin involvement can be subclassified into one of the three subtypes of cutaneous mastocytosis currently recognized by the World Health Organization (i.e., mastocytoma, maculopapular cutaneous mastocytosis and diffuse cutaneous mastocytosis); however, some patients may occasionally present with atypical skin lesions that cannot be ascribed to any of these disease subtypes. Here, we report three patients diagnosed with mastocytosis and an unusual cutaneous involvement mimicking Kaposi's sarcoma. Skin biopsies showed neoplastic mast cell infiltrates together with features commonly seen in acroangiodermatitis, and immunohistochemistry for human herpesvirus 8 was negative. One patient fulfilled the criteria for aggressive systemic mastocytosis, showed no response to cytoreductive therapy, and died because of disease progression. The remaining two patients had indolent and smoldering systemic mastocytosis, respectively, but they showed several features associated with an unfavorable prognosis such as extensive involvement of the hematopoiesis by the KIT D816V mutation, increased serum β2-microglobulin, and decreased serum lactate dehydrogenase. The presence of pseudo-Kaposi's sarcoma skin lesions is an uncommon finding in mastocytosis which may alert physicians to the possible existence of underlying features indicative of a poor prognosis.

Pleomorphic mastocytoma associated with loss of chromosome 5, PDGFRA, and HRAS mutations: A case of cutaneous mastocytosis with severe atypia and indolent behavior

A 21-year-old female presented with a 5-year history of an erythematous papule on her right breast. The biopsy showed a dense, dermal nodular infiltrate, extending focally into the subcutaneous tissue. The infiltrate was composed predominantly of pleomorphic cells with bi-lobed, multi-lobed, horseshoe, or ring-shaped nuclei. There was a smaller subset of monomorphous cells characterized by a round, reniform, or elongated single-lobed nucleus. Accompanying cells included few foamy histiocytes, lymphocytes, and numerous scattered eosinophils. No necrosis, vascular invasion, or ulceration was present. The pleomorphic and monomorphic granular cells were positive for Giemsa stain as well as for tryptase, CD117, CD68, CD2, and CD30 immunohistochemistry and negative for S100, CD1a, myeloperoxidase, lysozyme, and CD56. Clinical examination was negative for any additional similar lesions and serum tryptase was within normal limits. The bone marrow was not biopsied. In addition, fluorescent in situ hybridization revealed multiple clones with loss of number 5 chromosome and PDGFRA and HRAS mutations. The lesion did not recur or progress after a 6-year clinical follow-up. To our full knowledge, we report the first case of pleomorphic mastocytoma with loss of chromosome 5 and PDGFRA and HRAS mutations.

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.

Clinical features and survival of patients with indolent systemic mastocytosis defined by the updated WHO classification

BACKGROUND

In indolent systemic mastocytosis (ISM), several risk factors of disease progression have been identified. Previous studies, performed with limited patient numbers, have also shown that the clinical course in ISM is stable and comparable to that of cutaneous mastocytosis (CM). The aim of this project was to compare the prognosis of patients with ISM with that of patients with CM.

METHODS

We employed a dataset of 1993 patients from the registry of the European Competence Network on Mastocytosis (ECNM) to compare outcomes of ISM and CM.

RESULTS

We found that overall survival (OS) is worse in ISM compared to CM. Moreover, in patients with typical ISM, bone marrow mastocytosis (BMM), and smoldering SM (SSM), 4.1% of disease progressions have been observed (4.9% of progressions in typical ISM group, 1.7% in BMM, and 9.4% in SSM). Progressions to advanced SM were observed in 2.9% of these patients. In contrast, six patients with CM (1.7%) converted to ISM and no definitive progression to advanced SM was found. No significant differences in OS and event-free survival (EFS) were found when comparing ISM, BMM, and SSM. Higher risk of both progression and death was significantly associated with male gender, worse performance status, and organomegaly.

CONCLUSION

Our data confirm the clinical impact of the WHO classification that separates ISM from CM and from other SM variants.

Oxidative Stress in Children with Cutaneous Mastocytosis

Background: Thiols and ischemia-modified albumin (IMA) are novel biomarkers for the evaluation of the oxidative stress (OS) that has been associated with the pathogenesis of various neoplastic and inflammatory diseases. The aim of this study was to find out the dynamic thiol-disulfide homeostasis and IMA levels in patients with cutaneous mastocytosis (CM) to demonstrate the presence of the OS. Methods: A total of 36 patients with CM and 27 age- and sex-matched healthy participants were included in this study. Serum thiols and IMA levels were measured and compared between the 2 groups. Results: Levels of native thiol, total thiol, disulfide, disulfide/native thiol, disulfide/total thiol, native thiol/total thiol, and IMA were similar in both patients with CM and the control group. No significant difference was found with regard to mediator-releasing symptoms, clinical types, and remission status between the OS markers (thiol/disulfide variables and IMA levels) of the patients (P > 0.05). Conclusions: To our knowledge, this study is the first study in the literature that investigated thiol-disulfide homeostasis and IMA levels in pediatric patients with CM. Our study indicated that OS plays no role in the course of the pediatric CM.

Omalizumab in the treatment of adult patients with mastocytosis: A systematic review

BACKGROUND: Mastocytosis is associated with mast cell (MC) mediator-related symptoms for which limited therapies are available. OBJECTIVE: Our aim was to assess the efficacy and safety of omalizumab in the treatment of MC mediator-related symptoms in adult patients with mastocytosis. RESULTS: We identified one multi-centre retrospective cohort study (39 patients), one retrospective cohort study (13 patients), 4 case series and 10 case reports. No published controlled randomized study was identified. We included 69 patients (13 patients with cutaneous mastocytosis and 56 with systemic mastocytosis). The mean age was 48 years. Omalizumab maintenance dose was 300 mg for the majority of patients. The mean duration of treatment was 17 months. Treatment led to a tolerability of venom immunotherapy and to a complete resolution of severe reactions in all patients with post-honeybee sting anaphylaxis. Complete resolution of idiopathic anaphylaxis episodes was noted in 84% of the patients. Complete resolution of palpitations, gastrointestinal, cutaneous, neuropsychiatric, respiratory and musculoskeletal symptoms was observed at a rate of 43%, 29%, 27%, 11%, 9% and 0%, respectively. Efficacy was maintained for the entire duration of the treatment in all but four responders. Adverse events were reported for 13 patients. CONCLUSIONS AND CLINICAL RELEVANCE: Omalizumab appears to prevent some life-threatening reactions associated with mastocytosis and may be a good option to treat the associated symptoms. However, the evidence relied upon is observational, uncontrolled and from a small number of patients. A randomized controlled trial is needed to better understand the place of omalizumab in mastocytosis treatment.

Genotype and phenotype analysis of patients with pediatric cutaneous mastocytosis, especially wild-type KIT patients

Pediatric cutaneous mastocytosis (CM) is mainly attributed to gain-of-function mutations in KIT in mast cells. On the other hand, growing evidence suggests that CM patients exist without KIT mutations. To date, the association between the KIT mutation status and clinical phenotype has not been elucidated in pediatric CM, especially in patients with wild-type KIT. Nevertheless, genetic analysis has yet to be performed with whole KIT sequence of mast cells in Japanese patients with pediatric CM. In the present study, 11 Japanese patients with pediatric CM were analyzed to determine whether they had KIT mutations in their skin, and their clinical phenotypes were observed. The approximate frequency of patients with KIT mutation and that of wild-type KIT was almost consistent with the European analysis. The distribution of overall macules was similar between the patients with and without KIT mutations.

Telangiectasia macularis eruptiva perstans: a neglected type of mastocytosis with exclusively cutaneous involvement? A case series

Telangiectasia macularis eruptiva perstans (TMEP) is a rare form of cutaneous mastocytosis (CM). Although TMEP has been traditionally thought to be restricted to the skin, a recent retrospective multicentric study established a diagnosis with systemic involvement of mastocytosis in 47% patients affected by TMEP and aggressive systemic mastocytosis in 9%. To evaluate systemic involvement in patients affected by TMEP. We conducted a retrospective monocentric study among patients affected by TMEP visited in our dermatology clinic. Data regarding gender, age at diagnosis, duration of the disease before diagnosis, topography, clinical features, presence of extra-cutaneous symptoms, serum tryptase levels, and histopathological and bone marrow biopsy features were analysed. Among 119 patients classified with mastocytosis, eight patients (six males, two females) with TMEP and one female patient affected by mastocytosis in the skin, a TMEP variant, were retrospectively studied. The mean diagnostic delay was two years (range: 8-26 months). In two patients (25%), bone marrow involvement was identified and osteoporosis and hepatosplenomegaly were also found. The two patients with systemic involvement exhibited a statistically significant increase in serum tryptase levels (p < 0.05). The detection of KIT gene mutation in skin specimens revealed a somatic mutation, KITD816 V, only in these two patients. TMEP is a rare form of CM, often neglected. A correct and early diagnosis of TMEP is important to rule out systemic involvement of the disease. Detection of serum tryptase levels may be a useful, rapid, and non-invasive marker of systemic involvement.

Urticaria pigmentosa-like skin disease in a domestic shorthair cat

CASE SUMMARY

A 14-month-old castrated male domestic shorthair cat presented with an 8 month history of severe pruritus, alopecia, papules and excoriations. Initial evaluation and treatment prior to referral included skin scrape, cytology, two strict food trials, dermatophyte culture, and bacterial culture and sensitivity, as well as antibiotic therapy, empiric treatment for mites, steroids and ciclosporin A (Atopica; Elanco). The cat was referred to the Dermatology and Otology Clinic at the University of Illinois Veterinary Teaching Hospital for further diagnostics and treatment. Skin scrapes were unremarkable. Cytology showed rare bacteria and moderate neutrophils. The cat was given an injection of triamcinolone acetonide, which was ineffective. Oclacitinib (Apoquel; Zoetis) was given for 4 weeks with no improvement. A skin biopsy was performed, and histopathology showed large numbers of well-differentiated monomorphic mast cells with fewer eosinophils that diffusely infiltrated the superficial dermis, supportive of urticaria pigmentosa. Oral dexamethasone and cetirizine hydrochloride were initiated, and the cat responded favorably. At the time of writing, the cat continues to do well on cetirizine hydrochloride with only intermittent tapering courses of dexamethasone.

RELEVANCE AND NOVEL INFORMATION

To the best of our knowledge, this is the first reported case of urticaria pigmentosa in a domestic shorthair cat. This case also highlights the importance of biopsy after a thorough, systematic work-up in a cat with severe, intractable pruritus to reveal an uncommon disease pattern, as well as the efficacy of oral dexamethasone and cetirizine hydrochloride as a potential management option.

Immune response against HtrA proteases in children with cutaneous mastocytosis

Mast cells play an important role in both, the innate and adaptive immunity, however, clonal proliferation of abnormal mast cells in various organs leads to mastocytosis. A skin variant of the disease, cutaneous mastocytosis (CM) is the most frequent form of mastocytosis in children. HtrA proteases are modulators of important cellular processes, including cell signaling and apoptosis, and are related to development of several pathologies. The above and the observation that mast cells constitutively release the HtrA1 protein, prompted us to investigate a possible involvement of the HtrA proteins in pediatric CM. Levels of the serum autoantibodies (IgG) against the recombinant HtrA proteins (HtrA1-4) in children with CM (n=36) and in healthy controls (n=62) were assayed. Anti-HtrA IgGs were detected using enzyme linked immunosorbent assay (ELISA) and Western-blotting. In the CM sera, levels of the anti-HtrA1 and anti-HtrA3 autoantibodies were significantly increased when compared to the control group, while the HtrA protein levels were comparable. No significant differences in the anti-HtrA2 IgG level were found; for the anti-HtrA4 IgGs lower levels in CM group were revealed. In healthy children, the IgG levels against the HtrA1, -3 and -4 increased significantly with the age of children; no significant changes were observed for the anti-HtrA2 IgG. Our results suggest involvement of the HtrA1 and HtrA3 proteins in pediatric CM; involvement of the HtrA4 protein is possible but needs to be investigated further. In healthy children, the autoantibody levels against HtrA1, -3 and -4, but not against HtrA2, increase with age.

Prevalence of CD30 immunostaining in neoplastic mast cells: A retrospective immunohistochemical study

Mastocytosis is a rare disease characterized by clonal neoplastic proliferation of mast cells (MCs). It ranges from skin lesions as cutaneous mastocytosis (CM) which may spontaneously regress to highly aggressive neoplasms with multiorgan involvement corresponding to some aggressive systemic mastocytosis (ASM), mast cell leukemia (MCL), and/or mast cell sarcoma (MCS).There is increasing evidence of CD30 expression in neoplastic MCs of the bone marrow. This expression has been described almost exclusively in aggressive forms of systemic mastocytosis (SM).The aim of the present study is to evaluate CD30 expression both in cutaneous and systemic forms of mastocytosis. Forty-two mastocytosis cases were reviewed, including cutaneous (n = 29) and systemic (n = 13) forms to assess the prevalence of CD30 expression. Thirty-nine out of 42 (92.8%) cases were CD30 positive. In cases of CM, 28/29 (96.5%) cases were CD30 positive, 11/13 cases of SM (84.6%) were positive for CD30. MCs in normal skin biopsies and in urticaria lesions were CD30-negative. This study found that CD30 is also frequently expressed in CM as well as in systemic forms. This finding is a major departure from the prevailing concept that CD30 expression is often related to aggressive systemic forms of mastocytosis.

Acquired bilateral telangiectasia macularis eruptiva perstans: A unique clinical feature of photodamaging rather than a subtype of cutaneous mastocytosis

Telangiectasia macularis eruptiva perstans (TMEP) is a rare subtype of cutaneous mastocytosis, characterized by telangiectatic tan to brown macules on the trunk and extremities. Although TMEP has been descried as an uncommon disease in the literature, we often encounter patients with TMEP lesions in the outpatient clinic. We aimed to assess the clinical and histopathological characteristics of acquired bilateral TMEP, and the pathophysiological mechanism of acquired bilateral TMEP among these patients. We retrospectively reviewed 30 patients (28 men and 2 women) with acquired bilateral TMEP; multiple telangiectatic dark red to brown macules that were symmetrically distributed. The clinical characteristics and general histopathological findings of lesional skin were investigated. The number of mast cells was evaluated using immunohistochemical analysis with an antibody directed against c-kit (CD117). Acquired bilateral TMEP was predominantly localized on the sun-exposed area: the upper arm in 30 patients (100%), forearm in 19 patients (63.3%) and anterior chest in 15 patients (50%). A total of 16 patients (53.3%) showed at least one aggravating factor, including UV irradiation, alcohol use and heat exposure. Compared with the mast cell numbers in 19 age- and biopsy site-matched healthy controls (91 ± 29.0/mm² ), the number of mast cells in the papillary dermal skin of acquired bilateral TMEP patients was significantly increased (159 ± 37.2/mm² , P < 0.01). In addition, a significant difference in vessel numbers in the papillary dermis was observed between acquired bilateral TMEP patients and healthy controls (10.5 ± 1.9 vs 5.4 ± 1.0/mm² , P < 0.01). Acquired bilateral TMEP is a relatively common disorder in middle-aged Asian men. An increased number of mast cells and dilated vessels might be a photoaging-related reactive process of chronic sun-exposure, which consequently leads to the formation of characteristic telangiectatic hyperpigmentary macules through certain melanogenic mediators.

Narrow-band UVB phototherapy and psoralen-ultraviolet A photochemotherapy in the treatment of cutaneous mastocytosis: a study in 20 patients

BACKGROUND

In mastocytosis, the skin is almost invariably involved, and cutaneous symptoms deeply affect patients' quality of life.

METHODS

A retrospective observational analysis of patients affected by cutaneous mastocytosis (CM) and indolent systemic mastocytosis (ISM) treated with phototherapy/photochemotherapy (PUVA or NB-UVB) has been conducted. For each patient, total numbers of PUVA or NB-UVB exposures, the cumulative UV dose (J/cm² ), serum tryptase profile, and pruritus, before and after treatment, according to the visual analogue scale (VAS) were considered. Skin lesions of each patient were assessed, before and after treatment, according to a cutaneous scale score.

RESULTS

Twenty patients affected by CM and ISM were studied; in particular, 10 patients received NB-UVB therapy, and other 10 patients received PUVA. A statistically significant mean reduction of pruritus in both groups (P < 0.01) was observed. The number of treatments necessary to obtain symptom relief was significantly lower in the PUVA group, but the mean exposure dose was significantly higher, if compared to the NB-UVB group. Serum tryptase levels showed a downward trend. The cutaneous score improved in both groups.

LIMITATIONS

This study was a retrospective study with a small sample size and without a control group.

CONCLUSION

This work provides evidence that both NB-UVB and PUVA represent a safe and useful second-line therapy of the cutaneous symptoms in mastocytosis.

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.

Cutaneous mastocytosis with a mutation in the juxtamembrane domain of c-kit in a young laboratory beagle dog

Cutaneous mastocytosis, which resembles a subset of urticaria pigmentosa in humans, is rare in dogs. We herein report unrepresentative neoplastic proliferation of mast cells in ventral skin removed routinely from a nine-month-old female laboratory beagle dog at necropsy. A histological examination revealed diffuse extensive cellular infiltration from the superficial to deep dermis in most parts of the skin around the fourth and fifth mammary papilla without nodule formation. Tumor cells were fairly monomorphic, well-differentiated mast cells with round nuclei of small distinct nucleoli and moderate to abundant, slightly eosinophilic and granular cytoplasm. A perivascular arrangement of mast cells was noted at the margin of the lesions. Infiltration of eosinophils and degeneration of collagen were not observed in the dermis. Cutaneous mastocytosis was diagnosed based on these features. A sequence analysis of lesions revealed the deletion of Gln₅₅₅ to Ile₅₇₀ within the juxtamembrane domain of c-kit (exon 11).

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.

Childhood mastocytosis: results of a single center

AIM

We aimed to retrospectively evaluate histopathological, demographic and clinical findings of children with mastocytosis diagnosed with mastocytosis in our clinic.

MATERIAL AND METHODS

The files of 21 patients diagnosed with mastocytosis between 2000 and 2014 in our clinic were retrospectively analyzed.

RESULTS

All patients had cutaneous mastocytosis, 19 patients had urticaria pigmentosa and 2 patients had mastocytoma. The male-female ratio was: 1/1.6. The median age for onset of disease was 12.1 months and the disease occured in the newborn period in 3 patients. While all patients had eruption, 10 patients had pruritis, 1 patient had a bullous formation, 1 patient had abdominal pain and 1 patient had attacks of redness throughout the body and a sense of burning in the chest. Two patients had a positive familial history. The diagnosis was confirmed with skin biopsy in all patients. The median follow up time of the patients were 5 years. The patients were treated with H1, H2 antihistaminics, local moisturizing creams and topical corticosteroid drugs. The lesions resolved completely in 4 patients who reached to puberty and 7 patients had marked improvement in a 5.5 year-follow-up period. Ten patients had stabile lesions in a 3.6 year-follow-up period.

CONCLUSIONS

Most cases of childhood mastocytosis are observed in the form of cutaneous mastocytosis. The prognosis is good; the disease limits itself and is prone to regress in the adolescent period.

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.

Topical corticosteroids versus "wait and see" in the management of solitary mastocytoma in pediatric patients: a long-term follow-up

Management of patients affected by mastocytoma (MS) includes avoiding triggering factors of mast cell degranulation, and administration of symptomatic treatment. We evaluated topical steroid treatment efficiency on the clinical course of MS in a group of patients, comparing the results with another untreated group.We retrospectively evaluated clinical data of 176 patients under 15 years of age, affected by MS and referred to our Dermatological Pediatric Service from 1996 to 2010. Ninety-one of 176 children were treated with topical steroids. Follow-up was possible in 130 of 176 patients and lasted for 56.3 months on average. We compared 62 treated and 68 untreated patients. There was not statistic difference between the two groups: (i) in the number of healed or partially improved cases; and (ii) in the time of partial regression, although it is quicker with therapy. The time of healing is 16.4 months (on average) with treatment, and 34.7 months (on average, p = 0.001) without any treatment. The resolution of MS is independent of therapy administration, but the time of healing is statistically faster using the local steroids. An appropriate treatment with them is effective and safe, considering the long time needed for spontaneous resolution.

Cutaneous mastocytosis extending beyond a radiotherapy site: a form of radiodermatitis or a neoplastic phenomenon?

Ionising radiation is often used as an adjuvant in the management of breast cancer. Acute and chronic skin changes are well recognised complications associated with its use. We demonstrate a rare clinical presentation of cutaneous mastocytosis that occurred at the site of radiotherapy and then extended beyond this boundary, and ask whether this can be treated as a localised side effect of radiotherapy or whether the potential for systemic mastocytosis needs to be excluded.

Pediatric-onset mastocytosis: a long term clinical follow-up and correlation with bone marrow histopathology

BACKGROUND

Pediatric onset mastocytosis usually presents as urticaria pigmentosa; and less often as diffuse cutaneous mastocytosis. While the literature indicates that disease often resolves, there has been a move to more aggressive therapy for mastocytosis early in life. We addressed the long term prognosis of pediatric-onset disease by examining 17 children with mastocytosis which we had reported on in 1989 [1].

PROCEDURE

We successfully contacted 15 of these patients and data was collected regarding their clinical status. Original bone marrow specimens were re-stained, re-examined, and correlated with disease outcome using consensus criteria. Three of five patients with persistent disease underwent repeat bone marrow biopsies.

RESULTS

There was complete regression of disease as defined by cutaneous findings and symptoms (clinical disease severity) in 10 of 15 patients (67%). Three patients had major (20%) and two had partial regression of disease (13%). Repeat marrow examinations on three patients with persistent disease documented systemic mastocytosis based on marrow findings in one patient who had partial regression of disease and was the only patient with initial morphologic evidence of systemic disease. Of the remaining two patients, one demonstrated partial regression and the other major regression of disease; and neither had evidence of systemic mastocytosis.

CONCLUSION

This study demonstrates that initial bone marrow biopsies were prognostic in that those without evidence of systemic disease experienced disease regression; and that the long term prognosis for children managed symptomatically with mastocytosis is highly encouraging.