The Prevalence Of Osteoporosis Is Low in Adult Cutaneous Mastocytosis Patients

BACKGROUND

Systemic mastocytosis (SM) is a clonal disorder of mast cells (MCs) frequently associated with vertebral osteoporosis (OP) and subsequent vertebral fractures (VFs). The natural history of this OP remains unclear. Importantly, we do not know whether OP represents an early event triggered alongside MC abnormalities, and whether MC clonality is sufficient to trigger osteoporosis.

OBJECTIVE

To describe OP in patients with medullar clonality in cutaneous mastocytosis (CM) and monoclonal mast cell activation syndrome (MMAS) and to compare their osteoporosis characteristics with those of nonadvanced SM patients (bone marrow mastocytosis and indolent systemic mastocytosis).

METHODS

We retrospectively analyzed clinical, biological, and densitometric data of 27 CM, 13 MMAS, and 135 SM patients from the Mastocytosis Expert Center (CEREMAST) in Toulouse, France.

RESULTS

The OP (respectively 3.7, 30.8, and 34.1%) and VFs (0.0%, 15.4%, and 20%) were less frequent in CM than in MMAS and SM, despite the presence of clonal MCs in the bone marrow. Most patients with OP and VFs in the non-SM groups had the usual risk factors for OP. Interestingly, the only non-SM patient with a typical SM-like OP had high bone marrow tryptase, developed bone marrow KIT mutation during follow-up, and had a family history of SM. Our data show that OP is not a common clinical finding in CM but is frequent in MMAS. When OP and VFs occur in CM and MMAS patients, they differ from the usual phenotype of SM bone fragility.

CONCLUSIONS

Our findings suggest that, in most CM patients, the meaning and management of OP differs from that of OP in MMAS and nonadvanced SM. Prospective longitudinal studies and the validation of predictors are needed to identify CM and MMAS patients developing SM-related OP.

Diagnosis and management of systemic mastocytosis in a community hematology setting

BACKGROUND

Systemic mastocytosis (SM) is a rare and potentially severe hematologic disorder characterized by the clonal proliferation of mast cells (MCs) into various organs. The clinical manifestations of advanced SM are caused by the uncontrolled release of cytokines and vasoactive amines from MC and disease-induced organ dysfunction. Patients with SM typically present with symptoms such as flushing, pruritus, diarrhea, and headaches, but outcomes following active treatment have not been well characterized. In this study, the clinical characteristics, treatment patterns, and natural history of an SM patient cohort diagnosed and treated within a community hematology network in the United States is described.

METHODS

We identified 105 patients who were diagnosed and managed in one of 19 community hematology clinics up to an index date of 1 October 2022. Data collection included patient and disease characteristics, baseline biochemistry and hematology, SM diagnostic criteria being met, biomarkers tested, CD2 and/or CD25 expression in MCs as well as serum tryptase levels at presentation. Data abstraction also included supportive care drugs and anticancer therapy used, treatment response, reason for discontinuation, and overall survival by disease subtype.

RESULTS

A total of 105 SM patients were identified who met the inclusion criteria. The specific SM subtypes were indolent (47.6%), aggressive (9.5%), SM with an associated hematological neoplasm (19.0%), MC leukemia (1.9%), and subtype not documented (21.9%). Regardless of subtype, approximately 62% of patients did not receive SM-directed active therapy. Only 26% of patients with indolent systemic mastocytosis (ISM) received treatment compared to 65.6% with advanced subtypes. Relative to ISM cohort, the relative risk of death in patients with the advanced SM subtypes was approximately 15 times greater (hazard ratio = 15.0; 95% confidence interval: 3.3 to 66.5).

CONCLUSIONS

SM patients present with multiple underlying symptoms, within various disease subtypes that are difficult to diagnose in a timely manner. As a result, many patients do not receive active drug therapy for their disease. Therefore, greater disease awareness is required as well as new tools for earlier disease detection.

Systemic mastocytosis: 2023 update on diagnosis and management in adults

INTRODUCTION

Systemic mastocytosis (SM) is a complex and heterogeneous disease, characterized by the clonal accumulation of mast cells in one or more organs. In 2022 both the World Health Organization (WHO) and the International Consensus Classification (ICC) modified the diagnostic and classification criteria of SM. Moreover, the identification of new clinical and molecular variables has improved prognostic tools and led to increasingly individualized therapeutic strategies.

AREAS COVERED

The aim of this review is to present the updates introduced by the International Consensus Classification in diagnostic criteria of SM. In addition, we report the latest data available from the most important clinical trials in patients both with non-advanced and advanced disease, including elenestinib and bezuclastinib.

EXPERT OPINION

Diagnosis and classification of SM has evolved over years. The most recent WHO and ICC classification improved SM diagnostic work-up, providing clinicians with a clear and simplified diagnostic scheme. New approved targeted therapies such as midostaurin and avapritinib modified the treatment paradigm in patients in advanced stage, and next-generation inhibitors actually investigated in clinical trials are expected in the next future.

Mast Cell Disorders of the Gastrointestinal Tract: Clarity out of Chaos

Pathologists are increasingly asked to evaluate mast cell infiltrates in the gastrointestinal tract when there is clinical concern for systemic mastocytosis or a variety of functional disorders, including irritable bowel syndrome and mast cell activation syndrome. Neoplastic mast cells have established quantitative, morphologic, and immunohistochemical features that facilitate their identification in gastrointestinal mucosal biopsies. Specific qualitative and quantitative findings are lacking for inflammatory mast cell-mediated disorders. This review covers histopathologic features of mast cell disorders that affect the gastrointestinal tract and offers practical guidance for their assessment in mucosal biopsies.

Management of Advanced Systemic Mastocytosis and Associated Myeloid Neoplasms

Advanced systemic mastocytosis (AdvSM) is a heterogeneous group of disorders characterized by neoplastic mast cell-related organ damage and frequently associated with a myeloid neoplasm. The 3 clinical entities that comprise AdvSM are aggressive SM (ASM), SM-associated hematologic neoplasm, and mast cell leukemia. A gain-of-function KIT D816 V mutation is the primary oncogenic driver found in about 90% of all patients with AdvSM. Midostaurin, an oral multikinase inhibitor with activity against KIT D816V, and avapritinib, an oral selective KIT D816V inhibitor are approved for AdvSM.

Perioperative management of mastocytosis

PURPOSE

Patients with mastocytosis have an increased risk of anaphylaxis during surgical procedures with general anesthesia. Therefore, we reviewed the anesthesia course of a large cohort of patients with mastocytosis.

METHODS

We retrospectively reviewed adult and pediatric patients with mastocytosis who underwent surgical procedures with general anesthesia at Mayo Clinic from January 1, 2000, through June 30, 2021. We also included any procedures with general anesthesia that occurred during the 3-year period preceding mastocytosis diagnosis and designated the patients who underwent these procedures as having an unknown diagnosis at the time of their surgical procedure. We analyzed whether patients received chronic antimediator treatment for mastocytosis and/or prophylactic medications before the procedures. We also determined whether medications indicative of mastocytosis-related adverse events were intraoperatively administered.

RESULTS

We identified 113 patients who underwent 219 procedures during the study period; 25 procedures were performed before mastocytosis diagnosis. Of 194 procedures in patients with known mastocytosis, patients received chronic antimediator therapy and/or perioperative prophylactic medications for 178 (91.8%) procedures. Among these procedures, 10 were potentially complicated by mast cell activation, which was inferred from administration of inhaled albuterol (n = 3) or intravenous diphenhydramine (n = 8). In addition, there was only one case of intraoperative anaphylaxis which occurred in a patient who underwent anesthesia before mastocytosis diagnosis and therefore did not receive prophylaxis.

CONCLUSION

Intraoperative anaphylaxis can be the first presenting sign of mastocytosis. Patients with mastocytosis who received chronic antimediator therapy and/or preoperative prophylactic medications had an uneventful surgical course.

Proteomic and transcriptomic screening demonstrates increased mast cell-derived CCL23 in systemic mastocytosis

BACKGROUND

Systemic mastocytosis (SM) is a heterogeneous group of mast cell-driven diseases diagnosed by bone marrow sampling. However, there are a limited number of available blood disease biomarkers.

OBJECTIVE

Our aim was to identify mast cell-derived proteins that could potentially serve as blood biomarkers for indolent and advanced forms of SM.

METHODS

We performed a plasma proteomics screening coupled with single-cell transcriptomic analysis in SM patients and healthy subjects.

RESULTS

Plasma proteomics screening identified 19 proteins upregulated in indolent disease compared to healthy, and 16 proteins in advanced disease compared to indolent. Among these, 5 proteins, CCL19, CCL23, CXCL13, IL-10, and IL-12Rβ1, were higher in indolent relative to healthy and in advanced disease compared to indolent. Single-cell RNA sequencing demonstrated that CCL23, IL-10, and IL-6 were selectively produced by mast cells. Notably, plasma CCL23 levels correlated positively with known markers of SM disease severity, namely tryptase levels, percentage bone marrow mast cell infiltration, and IL-6.

CONCLUSION

CCL23 is produced predominantly by mast cells in SM, and CCL23 plasma levels are associated with disease severity, correlating positively with established markers of disease burden, thus suggesting that CCL23 is a specific SM biomarker. In addition, the combination of CCL19, CCL23, CXCL13, IL-10, and IL-12Rβ1 may be useful for defining disease stage.

Myeloid/lymphoid neoplasm with ZMYM2::FGFR1 rearrangement: A complex trilineage phenotypic and clonal evolution with associated genomic alterations

We report a case of myeloid/lymphoid neoplasm with ZMYM2::FGFR1 rearrangement (MLN^ZMYM2::FGFR1) exhibiting a complex disease evolution. This neoplasm initially presented as T-lymphoblastic lymphoma (T-LBL) in lymph node and myeloproliferative neoplasm (MPN) with eosinophilia in bone marrow, then transitioned to systemic mastocytosis (SM) likely accompanied by additional JAK3 and other mutations and finally transformed to acute myeloid leukemia (AML) accompanied by additional/secondary genetic abnormality (gain of chromosome 21, der(13)t(8;13), and RUNX1 mutation). To our knowledge, this is the first case of MLN^ZMYM2::FGFR1 with a complex trilineage/phenotypic [T-cell (T-LBL), mast cell (SM), and myeloid (MPN and AML)] lineage evolution.

Bone and Cytokine Markers Associated With Bone Disease in Systemic Mastocytosis

BACKGROUND

Mastocytosis encompasses a heterogeneous group of diseases characterized by tissue accumulation of clonal mast cells, which frequently includes bone involvement. Several cytokines have been shown to play a role in the pathogenesis of bone mass loss in systemic mastocytosis (SM), but their role in SM-associated osteosclerosis remains unknown.

OBJECTIVE

To investigate the potential association between cytokine and bone remodeling markers with bone disease in SM, aiming at identifying biomarker profiles associated with bone loss and/or osteosclerosis.

METHODS

A total of 120 adult patients with SM, divided into 3 age and sex-matched groups according to their bone status were studied: (1) healthy bone (n = 46), (2) significant bone loss (n = 47), and (3) diffuse bone sclerosis (n = 27). Plasma levels of cytokines and serum baseline tryptase and bone turnover marker levels were measured at diagnosis.

RESULTS

Bone loss was associated with significantly higher levels of serum baseline tryptase (P = .01), IFN-γ (P = .05), IL-1β (P = .05), and IL-6 (P = .05) versus those found in patients with healthy bone. In contrast, patients with diffuse bone sclerosis showed significantly higher levels of serum baseline tryptase (P < .001), C-terminal telopeptide (P < .001), amino-terminal propeptide of type I procollagen (P < .001), osteocalcin (P < .001), bone alkaline phosphatase (P < .001), osteopontin (P < .01), and the C-C Motif Chemokine Ligand 5/RANTES chemokine (P = .01), together with lower IFN-γ (P = .03) and RANK-ligand (P = .04) plasma levels versus healthy bone cases.

CONCLUSIONS

SM with bone mass loss is associated with a proinflammatory cytokine profile in plasma, whereas diffuse bone sclerosis shows increased serum/plasma levels of biomarkers related to bone formation and turnover, in association with an immunosuppressive cytokine secretion profile.

Recent advances in diagnosis and therapy in systemic mastocytosis

Mastocytosis is a heterogeneous neoplasm characterized by accumulation of neoplastic mast cells in various organs. There are three main types: cutaneous mastocytosis (CM), systemic mastocytosis (SM), and mast cell sarcoma. CM mainly affects children and is confined to the skin, whereas SM affects adults and is characterized by extracutaneous involvement, with or without cutaneous involvement. Most cases of SM have an indolent clinical course; however, some types of SM have aggressive behavior and a poor prognosis. Recent advances in the understanding of the molecular changes in SM have changed the diagnosis and treatment of aggressive and advanced SM subtypes. The International Consensus Classification and World Health Organization refined the diagnostic criteria and classification of SM as a result of accumulation of clinical experience and advances in molecular diagnostics. Somatic mutations in the KIT gene, most frequently KIT D816V, are detected in 90% of patients with SM. Expression of CD30 and any KIT mutation were introduced as minor diagnostic criteria after the introduction of highly sensitive screening methods. SM has a wide spectrum of clinical features, and only a few drugs are effective at treating advanced SM. Currently, the mainstay of SM treatment is limited to the management of chronic symptoms related to release of mast cell mediators. Small-molecule kinase inhibitors targeting the KIT-downstream and KIT-independent pathways were recently approved for treating advanced SM. I describe recent advances in diagnosis of SM, and review the currently available and emerging therapeutic options for SM management.

Cluster-Analytic Identification of Clinically Meaningful Subtypes in MCAS: The Relevance of Heat and Cold

BACKGROUND

Mast cell activation syndrome (MCAS) is a clinically heterogeneous disease with allergy-like symptoms and abdominal complaints. Its etiology is only partially understood and it is often overlooked.

AIMS

The aim of this study was to identify subgroups of MCAS patients to facilitate diagnosis and allow a personalized therapy.

METHODS

Based on data from 250 MCAS patients, hierarchical and two-step cluster analyses as well as association analyses were performed. The data used included data from a MCAS checklist asking about symptoms and triggers and a set of diagnostically relevant laboratory parameters.

RESULTS

Using a two-step cluster analysis, MCAS patients could be divided into three clusters. Physical trigger factors were particularly decisive for the classification as they showed remarkable differences between the three clusters. Cluster 1, labeled high responders, showed high values for the triggers heat and cold, whereas cluster 2, labeled intermediate responders, presented with high values for the trigger heat and low values for cold. The third cluster, labeled low responders, did not react to thermal triggers. The first two clusters showed more divers clinical symptoms especially with regard to dermatological and cardiological complaints. Subsequent association analyses revealed relationships between triggers and clinical complaints: Abdominal discomfort is mainly triggered by histamine consumption, dermatological discomfort by exercise, and neurological symptoms are related to physical exertion and periods of starvation. The reasons for the occurrence of cardiological complaints are manifold and triggers for respiratory complaints still need better identification.

CONCLUSION

Our study identified three distinct clusters on the basis of physical triggers, which also differ significantly in their clinical symptoms. A trigger-related classification can be helpful in clinical practice for diagnosis and therapy. Longitudinal studies should be conducted to further understand the relationship between triggers and symptoms.

Systemic mastocytosis mimicking blastic plasmacytoid dendritic cell neoplasm: a case report

BACKGROUND

Systemic mastocytosis (SM), a rare myeloid neoplasm, is defined as a clonal and neoplastic proliferation of mast cells in at least one extracutaneous organ(s). The pathologic diagnosis and treatment of SM are challenging.

CASE PRESENTATION

We presented a 44-year-old male patient who had endured abdomen discomfort for 4 years and diarrhea for 5 months. Colonoscopy and PET/CT found a protuberant lesion in the cecum with adjacent lymphadenopathy. Histopathology of the cecum biopsy showed diffuse infiltration of medium-sized round/oval cells in lamina propria with immunohistochemical expressions of CD45, CD117, CD25, CD68, CD123, CD56, CD4, and CD35, mimicking blastic plasmacytoid dendritic cell neoplasm. Sanger sequencing revealed missense mutation (D816V) in the exon 17 of KIT gene. Serum tryptase level was 38.56 ng/ml. No abnormality was found in skin examination and bone marrow biopsy. No primitive cells were observed in bone marrow smear and peripheral blood smear. The diagnosis of aggressive SM with intestinal tract involvement was established. The patient received avapritinib treatment at an initial dosage of 200 mg once daily and exhibited dramatic clinical improvement but memory impairment within 1 month. No recurrence was observed in 1-year follow-up at the adjusted avapritinib dose (75 mg once daily).

CONCLUSIONS

SM is very rare and should be considered in patients with long-term diarrhea symptoms and hematopoietic/lymphoid-appearing tumors. KIT D816V mutation contributes to the differentiation of CD123, CD4, and CD56 immunoreactive SM from blastic plasmacytoid dendritic cell neoplasm. The rare side-effect of memory impairment in this case helps to accumulate the experience of avapritinib in treating KIT D816V-mutant SM.

Prognostic Impact of Organomegaly in Mastocytosis: An Analysis of the European Competence Network on Mastocytosis

BACKGROUND

Organomegaly, including splenomegaly, hepatomegaly, and/or lymphadenopathy, are important diagnostic and prognostic features in patients with cutaneous mastocytosis (CM) or systemic mastocytosis (SM).

OBJECTIVES

To investigate the prevalence and prognostic impact of 1 or more organomegalies on clinical course and survival in patients with CM/SM.

METHODS

Therefore, 3155 patients with CM (n = 1002 [32%]) or SM (n = 2153 [68%]) enrolled within the registry of the European Competence Network on Mastocytosis were analyzed.

RESULTS

Overall survival (OS) was adversely affected by the number of organomegalies (OS: #0 vs #1 hazard ratio [HR], 4.9; 95% CI, 3.4-7.1, P < .001; #1 vs #2 HR, 2.1, 95% CI, 1.4-3.1, P < .001; #2 vs #3 HR, 1.7, 95% CI, 1.2-2.5, P = .004). Lymphadenopathy was frequently detected in patients with smoldering SM (SSM, 18 of 60 [30%]) or advanced SM (AdvSM, 137 of 344 [40%]). Its presence confered an inferior outcome in patients with AdvSM compared with patients with AdvSM without lymphadenopathy (median OS, 3.8 vs 2.6 years; HR, 1.6; 95% CI, 1.2-2.2; P = .003). OS was not different between patients having organomegaly with either ISM or SSM (median, 25.5 years vs not reached; P = .435). At time of disease progression, a new occurrence of any organomegaly was observed in 17 of 40 (43%) patients with ISM, 4 of 10 (40%) patients with SSM, and 33 of 86 (38%) patients with AdvSM, respectively.

CONCLUSIONS

Organomegalies including lymphadenopathy are often found in SSM and AdvSM. ISM with organomegaly has a similar course and prognosis compared with SSM. The number of organomegalies is adversely associated with OS. A new occurrence of organomegaly in all variants of SM may indicate disease progression.

Systemic mastocytosis with myeloid sarcoma and B-CLL: molecular and clonal heterogeneity in a rare case of SM-AHN with review of literature

BACKGROUND

Systemic mastocytosis (SM) is a rare myeloproliferative disease that results from a clonal proliferation of abnormal mast cells in one or more extra-cutaneous organs. Systemic mastocytosis with an associated hematological neoplasm (SM-AHN) is the second most common subgroup and is diagnosed when WHO criteria for both SM and a hematological neoplasm of non-mast cell lineage are met. The SM-AHN category as currently proposed is highly heterogeneous in terms of pathogenesis, clinical presentation, and prognosis.

CASE PRESENTATION

We present the first reported case of SM-AHN associated with two hematological malignancies of different lineages, a monocytic myeloid sarcoma and a B-cell chronic lymphatic leukemia. Cytogenetic and molecular analyses revealed a distinct clonal origin of the two associated malignancies. The SM-myeloid sarcoma clone demonstrated an abnormal karyotype, trisomy 8 and del(13)(q12.3q14.3), as well as mutations in KITD816V, DNMT3A and RUNX1. The DNMT3A mutation could be detected years before disease onset, supporting its potential role as early driver of leukemogenesis. No genetic aberrations could be identified in the CLL clone, which is assumed to present coincidentally.

CONCLUSIONS

This report highlights the importance of full diagnostic work-up in SM patients in whom an associated hematological malignancy is suspected. Moreover, the importance of genetic analysis is highlighted, as it provides additional insights in the underlying clonal pathogenesis of different phenotypes, can aid in risk stratification, and may help identify potential therapy targets.

Acute abdomen due to anaphylactic intestinal edema associated with systematic mastocytosis: a case report

BACKGROUND

Among various anaphylactic conditions resulting in acute abdomen, mast cell activation disorders, although rare, are included in the differential diagnosis.

CASE PRESENTATION

This report describes a 63-year-old Caucasian man who was brought to the emergency room with sudden onset abdominal pain, vomiting, and diarrhea, with breathing difficulty, and with facial swelling after quarrelling with an acquaintance. Computed tomography showed edematous and swollen intestines, consistent with splenomegaly. Physical findings included maculopapular cutaneous mastocytosis. He also had a long history of repeated episodes of anaphylaxis requiring occasional epinephrine auto-injector administration; however, the precise cause of anaphylaxis was previously undetermined. Blood tests showed high serum concentrations of soluble IL-2R and tryptase, suggesting mast cell-related disease. Subsequent biopsies of his bone marrow and cutaneous rash confirmed the diagnosis of systemic mastocytosis (SM).

CONCLUSION

SM was diagnosed in a patient with acute abdomen who visited the emergency room.

Clinical challenge for gastroenterologists–Gastrointestinal manifestations of systemic mastocytosis: A comprehensive review

Mastocytosis is a rare and heterogeneous disease characterized by various clinical and biological features that affect different prognoses and treatments. The disease is usually divided into 2 principal categories: cutaneous and systemic disease (SM). Clinical features can be related to mast cell (MC) mediator release or pathological MC infiltration. SM is a disease often hard to identify, and the diagnosis is based on clinical, biological, histological, and molecular criteria with different specialists involved in the patient’s clinical work-up. Among all manifestations of the disease, gastrointestinal (GI) symptoms are common, being present in 14%-85% of patients, and can significantly impair the quality of life. Here we review the data regarding GI involvement in SM, in terms of clinical presentations, histological and endoscopic features, the pathogenesis of GI symptoms, and their treatment.

Nontryptase Urinary and Hematologic Biomarkers of Mast Cell Expansion and Mast Cell Activation: Status 2022

Quantitation of urinary metabolites of histamine, prostaglandin D₂, and leukotriene E₄ can fill the gap in our current efforts to improve diagnosis and management of symptomatic patients with systemic mastocytosis, and/or mast cell activation syndrome, In addition, patients symptomatic due to mast cell activation but who do not meet all the criteria for mast cell activation syndrome can have elevated baseline mediator metabolites. Serum tryptase levels have been the workhorse in diagnosing these disorders, but it has several drawbacks including the need to obtain acute and baseline samples, which require 2 visits to health care facilities and 2 venipunctures. Recently, increased baseline tryptase level has been reported in hereditary alpha tryptasemia, complicating diagnostic possibilities of an increased baseline tryptase level. Furthermore, no treatment can specifically be targeted at tryptase itself. In contrast, the finding of 1 or more elevated urinary levels of histamine, prostaglandin D₂, and/or leukotriene E₄ metabolites (1) greatly narrows diagnostic possibilities for causes of symptoms; (2) informs the practitioner what specific metabolic pathways are involved; and (3) targets the treatment in a specific, direct fashion. As a bonus, baseline spot/random urine samples can be obtained by the patients themselves and repeated at exactly the correct time when symptoms occur.

Anaesthesia in a parturient with systemic mastocytosis

Mastocytosis is characterized by clonal expansion of mast cells, with abnormal accumulation in different organs. Perioperatively, numerous stimuli may lead to the release of vasoactive substances by mast cells. Parturients with systemic mastocytosis pose a challenge to the anesthesiologist: on one hand, the pain and stress of labor may lead to greater mast cell activation and, on the other, the administration of drugs that may possibly trigger the release of mast cell mediators. The authors describe a case of a 34-year-old pregnant woman with systemic mastocytosis who requests labor analgesia. An epidural analgesia was performed after induction of labor, after considering anesthetic particularities. The epidural procedure, labor and delivery were uneventful. A review of systemic mastocytosis is provided and its anesthetic considerations are discussed.

Mast cell neoplasm: a challenging pathological diagnosis

Systemic mastocytosis (SM) is a myeloid neoplasm characterized by abnormal growth and accumulation of neoplastic mast cells in at least one extracutaneous site. Clinical presentation and course are variable, most patients developing an indolent disease and some, an aggressive/leukemic form. Because of its rarity, most physicians are unfamiliar with this disease and do not readily diagnose it. In the present retrospective study, the authors describe 12 patients diagnosed with mast cell neoplasm. Cases were selected from three institutions from Campinas and São Paulo City, Brazil. Morphological features and diagnostic pitfalls are emphasized. Patients' age ranged from 15 to 81 years (mean 51.6 years). Male and female were affected similarly (1:1). Ten patients were classified as aggressive systemic mastocytosis (SM), one patient as SM with an associated acute promyelocytic leukemia with t(15;17), and one patient with mast cell sarcoma. Most common clinical findings included anemia (9 patients), thrombocytopenia (3 patients) and skin lesions (3 patients). Bone marrow was involved in 11 patients at diagnosis, followed by skin (5 patients). Five morphological patterns were present: mast cell aggregates (5), plasmacytoid (4), monocytoid (2), spindle cell (2) and epithelioid/pleomorphic (1); two patients showed two histological patterns. In all cases neoplastic cells were positive for CD117/C-KIT. C-KIT D816V mutation was present in four patients, C-KIT K509I in two, and del(7q22) in one; in five cases no mutational status was available. Despite limited resources, basically morphology and a restricted immunohistochemical panel, it is possible to diagnose mast cell neoplasm. Of note, pathologist should recognize the different morphological variants of the disease and include the adequate markers when requesting immunohistochemical studies.

Reproducibility of Symptom Sequences Across Episodes of Recurrent Anaphylaxis

BACKGROUND

Anaphylactic reactions may present with varying levels of severity, ranging from mild multisystem involvement to severe, and sometimes fatal, anaphylaxis. The severity of anaphylaxis is variable from one reaction to the next within the same individuals.

OBJECTIVE

To compare the temporal sequence of symptoms within individuals and between individuals across multiple anaphylactic reactions.

METHODS

Patients were evaluated for recurrent anaphylaxis in a tertiary care allergy clinic between 2012 and 2018. At each visit, patients were asked to record the temporal sequence in which symptoms of anaphylaxis appeared. These data were recorded at each visit and retrieved through retrospective chart review. Patients with a history of ≥2 anaphylactic reactions were included; those with anaphylaxis due to multiple allergens were excluded. The Fleiss Kappa method was used to assess reproducibility of the order of appearance of specific symptoms during anaphylaxis within individual patients and between individuals with similar triggers.

RESULTS

The mean patient age was 35.6 years (standard deviation = 13.9; range: 1-68 years); 113 of 149 (76%) patients were female. The mean Fleiss Kappa reproducibility score within individuals was 0.94, 5th percentile was 0.53, and 95th percentile was 1.0. The mean Kappa score between individuals was -0.03 (range, -0.14 to 0.05). Among the 16 of 149 patients who recorded reactions of varying severity grades, the mean within-patient Kappa score was 0.96.

CONCLUSION

Individual patients experience reproducibly stereotypic anaphylactic reactions over time, which are unique to a given patient, irrespective of the cause of anaphylaxis, including foods, medications, mast cell disorders, and idiopathic anaphylaxis. In contrast, symptom sequences during anaphylaxis are not reproducible between individuals.

Mast Cell Sarcoma of the Retroperitoneum With Concurrent Systemic Mastocytosis and an Undisclosed Associated Hematologic Neoplasm: A Case Report

Mastocytosis is a rare disorder affecting both children and adults by gathering of functionally defective mast cells in the body’s tissues. The World Health Organization (WHO) classified mastocytosis into cutaneous mastocytosis, systemic mastocytosis (SM), and mast cell sarcoma (MCS). We hereby present a case of retroperitoneal MCS with concurrent systemic mastocytosis and an undisclosed associated hematological neoplasm (SM-undisclosed AHN). The diagnosis of MCS and SM was made after the second biopsy over retroperitoneal mass, lymph node, and ovary for rapidly progressive disease with the presentation of unexplained recurrent flushing, palpitation, and shock, in addition to abdominal pain. A clonal myeloid neoplasm was also suspected by the karyotype and hemogram data. Unfortunately, the patient succumbed to the disease quickly. Apart from this unique case, the previously reported cases of SM with MCS in the literature were also reviewed.

[Successful outcome of allogeneic hematopoietic stem cell transplantation for systemic mastocytosis complicated with acute myeloid leukemia]

A 60-year-old woman developed a fifth thoracic spine fracture with progressive paraplegia and underwent posterior spine fusion in June 2018. Based on the histopathological analysis of the surgical specimen, she was diagnosed with KIT D816V-positive systemic mastocytosis (SM). In June 2019, peripheral blood examination revealed remarkable eosinophilia. She was given prednisolone, which resulted in the resolution of eosinophilia. In May 2020, she developed acute myeloid leukemia (AML). Induction therapy was initiated and complete remission achieved. Subsequently, she received one course of consolidation therapy and allogeneic hematopoietic stem cell transplantation (allo-SCT). Although the residual mast cell tumor aggravated during chemotherapy for AML, the tumor regressed after allo-SCT, suggesting a graft-versus-mastocytosis effect. Nine months after the transplantation, the patient is alive and healthy without recurrence of AML and SM.

[Influenza A: H1N1 post-viral membranoproliferative glomerulonephritis occurring in aggressive systemic mastocytosis: Case report and literature review]

Systemic mastocytosis is characterised by tissular infiltration and a cytokine storm due to mast cells excessive proliferation and activation. Herein, we report an extraordinary case of AH1N1 influenza post-viral glomerulonephritis occurring in the course of an aggressive systemic mastocytosis with an associated hematological neoplasm. Because of a multisystemic involvement including the liver and lungs, we treated mastocytosis with midostaurin (multiple inhibitor of kinase protein), anti H1/H2 blockers and dexamethasone as first line treatment. One month later and despite vaccination, he developed a severe acute lung injury with respiratory distress due to AH1N1 influenza in association with the nephrotic syndrome. Kidney biopsy disclosed a membranoproliferative glomerulonephritis that was successfully treated with mycophenolate mofetil. Only a few cases of influenza post-viral or post-vaccination glomerulonephritis are documented in the medical literature. This is an exceptional association of uncommon conditions occurring within only a few months in the same patient.

Avapritinib in the Treatment of Systemic Mastocytosis: an Update

PURPOSE OF REVIEW

Patients with systemic mastocytosis, a dangerous and rare myeloid neoplasm, have long had few therapies available to them and, historically, rarely achieved from significant disease control. However, research and translational developments over the last decade have led to promising new options for disease management. In this review, we briefly outline the history of treatment for systemic mastocytosis and subsequently focus on the clinical development and potential applications of avapritinib (previously known as BLU-285), a potent and selective oral inhibitor of the tyrosine kinase most commonly mutated in this condition.

RECENT FINDINGS

Phase I data and recent phase II data have demonstrated both safety and efficacy of this agent used as monotherapy, even in patients who have progressed on other targeted therapy. Studies to date have focused on patients with the most aggressive disease, but new trials in indolent mastocytosis are accruing currently. Over the next several years, one may anticipate finalized, peer-reviewed, and formally published data for this agent in both advanced systemic and indolent mastocytosis. Evidence from these early studies will also likely highlight where more research is needed.

Systemic Mastocytosis: Radiological Point of View

Radiological diagnosis of systemic mastocytosis (SM) can be hard to establish. This difficulty is mainly due to the variable radiological features involving many organ systems (e.g., respiratory, cardiovascular, lympho-reticular, digestive systems, and most commonly skin), and above all, to the broad spectrum of skeletal findings. Skeletal involvement is the most common and prominent imaging feature in patients with SM and represents a prognostic factor as it may entail an aggressive course of the disease. Diagnosis, largely established by histological evaluation of a bone marrow trephine biopsy, supplemented by imaging modalities such as radiography, CT, and magnetic resonance imaging, requires a team approach between the hematologist, radiologist, and pathologist. The general radiologist needs to be familiar with the imaging findings because they may be the first to suggest the correct diagnosis. The primary purpose of this review article was to equip clinicians with pertinent radiological semiotics by presenting relevant radiological features that assist early diagnosis and selection of an effective treatment.

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.

Systemic Mastocytosis: Molecular Landscape and Implications for Treatment

Over the past decade, we have witnessed significant advances in the molecular characterization of systemic mastocytosis (SM). This has provided important information for a better understanding of the pathogenesis of the disease but has also practically impacted the way we diagnose and manage it. Advances in molecular testing have run in parallel with advances in therapeutic targeting of constitutive active KIT, the major driver of the disease. Therefore, assessing the molecular landscape in each SM patient is essential for diagnosis, prognosis, treatment, and therapeutic efficacy monitoring. This is facilitated by the routine availability of novel technologies like digital PCR and NGS. This review aims to summarize the pathogenesis of the disease, discuss the value of molecular diagnostic testing and how it should be performed, and provide an overview of present and future therapeutic concepts based on fine molecular characterization of SM patients.

Anesthetic considerations in a laboring woman with systemic mastocytosis

Mastocytosis is characterized by clonal expansion of mast cells, with abnormal accumulation in different organs. Perioperatively, numerous stimuli may lead to the release of vasoactive substances by mast cells. Parturients with systemic mastocytosis pose a challenge to the anesthesiologist: on one hand, the pain and stress of labor may lead to greater mast cell activation and, on the other, the administration of drugs that may possibly trigger the release of mast cell mediators. The authors describe a case of a 34-year-old pregnant woman with systemic mastocytosis who requests labor analgesia. An epidural analgesia was performed after induction of labor, after considering anesthetic particularities. The epidural procedure, labor and delivery were uneventful. A review of systemic mastocytosis is provided and its anesthetic considerations are discussed.

Systemic mastocytosis: The roles of histamine and its receptors in the central nervous system disorders

Mastocytosis is a rare disease of clonal hematological disorders characterized by a pathological accumulation of Mast Cells (MCs) in different tissues, with variable symptomatology and prognosis. Signs and symptoms of Systemic Mastocytosis (SM) are due to pathological infiltration of MCs and to the release of chemical mediators, mainly histamine. Patients with SM may also present with neurological symptoms or complications. The pathophysiology of these neurological disorders remains uncertain to this day, but it can be associated with the infiltration of tissue mastocytes, release of mastocytes' mediators or both. Moreover, there is a lot to understand about the role of neurological symptoms in SM and knowing, for example, what is the real frequency of neurological disorders in SM and if is present a relation between other SM subtypes, because it has been noted that the alteration of the histamine expression may be an initiating factor for susceptibility, gravity and progression of the epigenetic disease. In this review we explain the possible pathophysiological mechanism about neurological symptomatology found in some patients affected by SM, describing the role of histamine and its receptors in the nervous system and, in light of the results, what the future prospects may be for a more specific course of treatment.

Divergent PGD2 and leukotriene C4 metabolite excretion following aspirin therapy: Ten patients with systemic mastocytosis

Aspirin-exacerbated respiratory disease and some cases of chronic idiopathic urticaria are disorders in which increased baseline urinary excretion of leukotriene(LT)E4 further increases following aspirin administration. Increased urinary excretion of the metabolites of prostaglandin D2, 11β-prostaglandin(PG)F2α and (2,3-dinor)-11β-PGF2α, have been documented in systemic mastocytosis (SM) and in mast cell activation syndrome (MCAS). Symptoms due to increased baseline and/or episodic release of PGD2 can be prevented with aspirin, an inhibitor of cyclooxygenase (COX)1 and COX2. Here by retrospective chart review we discovered 8 of 10 patients with SM in whom normalization of an elevated urinary (2,3-dinor)-11β-PGF2α occurred with aspirin therapy also had a parallel increased excretion of LTE4 by an average of nearly 13-fold. How widespread this phenomenon occurs in SM is unknown; however, this occurrence needs to be considered when interpreting changes in these urinary mast cell mediator metabolites during aspirin therapy.

The Genetic Basis and Clinical Impact of Hereditary Alpha-Tryptasemia

Hereditary alpha-tryptasemia (HαT) is an autosomal dominant genetic trait found in 4% to 6% of the general population and defined by excess copies of alpha-tryptase at TPSAB1. Elevated basal serum tryptase (sBT >8 ng/mL) is a defining feature of HαT and appears to result from increased pro-alpha-tryptase synthesis and secretion rather than mast cell activation. It is estimated that approximately one-third of individuals with HαT have associated symptoms, including cutaneous, gastrointestinal, atopic, musculoskeletal, autonomic, and neuropsychiatric manifestations. HαT is found at a disproportionately high rate in systemic mastocytosis and idiopathic anaphylaxis, and is a modifying factor that independently increases the incidence and severity of anaphylaxis. The varied phenotypes associated with HαT may, in part, result from coinheritance of other genetic variants, increased expression of α-/ß-tryptase heterotetramers, and/or overexpression of pro-alpha-tryptase, although further studies are needed. There is an accurate diagnostic test available to confirm HαT in patients that can be used in combination with sBT to help risk-stratify individuals in whom bone marrow biopsy is being considered. There is no specific treatment for symptoms associated with HαT, and management is focused on controlling clinical manifestations with mast cell mediator antagonists, aspirin, inhalers, epinephrine, omalizumab, and involvement of other specialists.

Proceedings from the Inaugural American Initiative in Mast Cell Diseases (AIM) Investigator Conference

The American Initiative in Mast Cell Diseases (AIM) held its inaugural investigator conference at Stanford University School of Medicine in May 2019. The overarching goal of this meeting was to establish a Pan-American organization of physicians and scientists with multidisciplinary expertise in mast cell disease. To serve this unmet need, AIM envisions a network where basic, translational, and clinical researchers could establish collaborations with both academia and biopharma to support the development of new diagnostic methods, enhanced understanding of the biology of mast cells in human health and disease, and the testing of novel therapies. In these AIM proceedings, we highlight selected topics relevant to mast cell biology and provide updates regarding the recently described hereditary alpha-tryptasemia. In addition, we discuss the evaluation and treatment of mast cell activation (syndromes), allergy and anaphylaxis in mast cell disorders, and the clinical and biologic heterogeneity of the more indolent forms of mastocytosis. Because mast cell disorders are relatively rare, AIM hopes to achieve a coordination of scientific efforts not only in the Americas but also in Europe by collaborating with the well-established European Competence Network on Mastocytosis.

Scoring the Risk of Having Systemic Mastocytosis in Adult Patients with Mastocytosis in the Skin

BACKGROUND

Mastocytosis in adults often presents with skin lesions. A bone marrow biopsy is necessary to confirm or exclude the presence of systemic mastocytosis (SM) in these cases. When a bone marrow biopsy is not performed, the provisional diagnosis is mastocytosis in the skin (MIS). No generally accepted scoring system has been established to estimate the risk of SM in these patients.

OBJECTIVE

To develop a risk score to predict SM in adults with MIS.

METHODS

We examined 1145 patients with MIS from the European Competence Network on Mastocytosis Registry who underwent a bone marrow biopsy. A total of 944 patients had SM and 201 patients had cutaneous mastocytosis; 63.7% were female, and 36.3% were male. Median age was 44 ± 13.3 years. The median serum tryptase level amounted to 29.3 ± 81.9 ng/mL. We established a multivariate regression model using the whole population of patients as a training and validation set (bootstrapping). A risk score was developed and validated with receiver-operating curves.

RESULTS

In the multivariate model, the tryptase level (P < .001), constitutional/cardiovascular symptoms (P = .014), and bone symptoms/osteoporosis (P < .001) were independent predictors of SM (P < .001; sensitivity, 90.7%; specificity, 69.1%). A 6-point risk score was established (risk, 10.7%-98.0%) and validated.

CONCLUSIONS

Using a large data set of the European Competence Network on Mastocytosis Registry, we created a risk score to predict the presence of SM in patients with MIS. Although the score will need further validation in independent cohorts, our score seems to discriminate safely between patients with SM and with pure cutaneous mastocytosis.

Systemic mastocytosis revisited with an emphasis on skeletal manifestations

Systemic mastocytosis (SM) is a rare form of mastocytosis that can affect various organ systems. Bone involvement is the most common and prominent imaging feature in patients with SM regardless of the subtype. Furthermore, bone involvement is a prognostic factor as it may entail an aggressive course of the disease. Diagnosis is established by bone marrow biopsy complemented by imaging modalities such as radiography, CT, and magnetic resonance (MR) imaging. The radiographic and CT appearances are that of sclerotic, lytic, or mixed patterns with focal or diffuse distribution, involving primarily the axial skeleton and the ends of the long bones. Bone marrow infiltration is best recognized on MR imaging. Osteoporosis is common in SM; thus, a bone mineral density measurement at lumbar spine and proximal femur by dual-energy X-ray absorptiometry should be obtained. Imaging plays a huge part in the diagnostic process; when skeletal imaging findings are carefully interpreted and correlated with clinical features, they can lead to the suspicion of SM. The primary aims of this review article were to focus on the role of imaging in detection and characterization of skeletal patterns of SM and to discuss relevant clinical features that could facilitate prompt and correct diagnosis.

Pancreatic neuroendocrine tumor presenting in indolent systemic mastocytosis: A case report

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Systemic mastocytosis and neuroendocrine tumors may present with similar symptoms.

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Co-occurrence of both diseases may be due to activating mutations in KIT.

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Recognition of these distinct diseases is necessary to ensure timely treatment.

Introduction

Systemic mastocystosis, a disorder of clonal mast cell expansion presents with symptoms of flushing, pruritus, musculoskeletal pain, gastrointestinal cramping and vascular instability. Patients with neuroendocrine tumors may present with similar symptoms due to the release of vasoactive mediators in both diseases. We report the co-occurrence of systemic mastocytosis and a neuroendocrine pancreatic tumor for which the patient received disease-specific treatment.

Case presentation

A 58-year-old woman with a history of indolent systemic mastocytosis and a serum tryptase of 51 ng/mL was diagnosed with a solid pancreatic lesion on ultrasound when assessing for organomegaly. Lesional biopsy was consistent with a pancreatic neuroendocrine tumor which was successfully resected.

Discussion

Presenting symptoms such as skin rashes, flushing, fatigue and diarrhea, are similar for systemic mastocytosis and neuroendocrine tumors. The co-occurrence of both diseases has not been previously reported. Activating mutations in KIT, which are a hallmark of systemic mastocytosis, may drive neoplastic proliferation in neuroendocrine tumors. Furthermore, mast cells infiltrating pancreatic tissue may have a trophic effect on the development of pancreatic neuroendocrine tumors.

Conclusion

While challenging to diagnose both diseases presenting with similar symptoms, recognition of these distinct diseases is necessary to ensure timely treatment.

Catching the clinical and biological diversity for an appropriate therapeutic approach in systemic mastocytosis

Systemic mastocytosis (SM) is a rare disease calling for integrated approaches involving onco-hematologic competences for appropriate clinical management and treatment. The wide variability of manifestations and disease course claims for an accurate risk stratification, currently relying on the appraisal of the benefit/risk ratio of treatment modalities within indolent and advanced variants according to WHO classification. More objective parameters are progressively incorporated and integrated into comprehensive models, on which to support the adoption of therapeutic strategies, since the mere clinical distinction between mediator-related signs/symptoms and “true” organ damage can sometimes be complicated. The development of novel targeted drugs is progressively extending the therapeutic alternatives available, which ranges from conventional agents such as interferon and cladribine, to the more modern approach based on KIT inhibition. Ultimately, the choice of the most appropriate therapy should be rationalized on the basis of the clinical picture and molecular data. The focus of the present review is on the areas still open in the current evaluation of SM patients, particularly when considering the need of a treatment.

[Tryptase: A practical guide for the physician]

Tryptase is the most abundant endopeptidase released by mast cells degranulation, involved in many pro and anti-inflammatory processes. Normal serum tryptase range is 0-11.4 μg/L. Tryptase is a useful diagnostic tool for anaphylaxis, systemic mastocytosis (SM) and mast cell activation syndrome (MCAS), where specific threshold values must be used. SM diagnosis criteria include evidence of dense mast cell infiltrate either in the bone marrow or the affected organ (such as skin), presence of KIT D816V mutation and elevated serum tryptase level (>20 μg/L). In SM, tryptase level is correlated with the burden of mast cells in bone marrow. MCAS should be considered in case of severe and recurrent typical clinical signs of systemic mast cell activation involving at least two organs, associated with an increase in serum tryptase level of 20% + 2 μg/L from the individual's baseline. Anaphylaxis is the most severe among hypersensitivity reactions. A clonal mast cell disorder is a central question in anaphylaxis and appropriate explorations should be conducted in these patients. Triggers for anaphylactic reactions vary significantly in the general population and in patients with MS or MCAS. Finally, physicians must be aware of the many pathological and physiological situations that affect tryptase levels.

Gastrointestinal manifestations of hypereosinophilic syndromes and mast cell disorders: a comprehensive review. Clin Rev Allergy Immunol. 2018;. [PMID: 30003499 DOI: 10.1007/s12016-018-8695-y]

Hypereosinophilic syndrome and mastocytosis are relatively rare proliferative diseases encountered in the general population. However, allergists frequently consider these disorders in the differential of patients presenting with gastrointestinal, pulmonary, cutaneous, and allergic symptoms. Gastrointestinal symptoms are some of the most frequent and/or debilitating aspects of both disease states and in many cases lead to poor quality of life and functional limitation for the patient. They are the third most common clinical manifestation in hypereosinophilic syndrome and have been found to be the most distressful aspect of the disorder in those with systemic mastocytosis. Both eosinophils and mast cells play integral parts in normal gut physiology, but when and how exactly their effector functionality translates into clinically significant disease remains unclear, and the available literature regarding their pathophysiology remains sparse. Eosinophils and mast cells even, in fact, may not necessarily function in isolation from each other but can participate in bidirectional crosstalk. Both are affected by similar mediators and can also influence one another in a paracrine fashion. Their interactions include both production of soluble mediators for specific eosinophil and mast cell receptors (for example, eosinophil recruitment and activation by mast cells releasing histamine and eotaxin) as well as direct physical contact. The mechanistic relationship between clonal forms of hypereosinophilia and systemic mastocytosis has also been explored. The nature of gastrointestinal symptomatology in the setting of both hypereosinophilic syndrome and mast cell disease is frequently manifold, heterogeneous, and the lack of better targeted therapy makes diagnosis and management challenging, especially when faced with a substantial differential. Currently, the management of these gastrointestinal symptoms relies on the treatment of the overall disease process. In hypereosinophilia patients, systemic corticosteroids are mainstay, although steroid-sparing agents such as hydroxyurea, IFN-α, methotrexate, cyclosporine, imatinib, and mepolizumab have been utilized with varying success. In mastocytosis patients, anti-mediator therapy with antihistamines and mast cell stabilization with cromolyn sodium can be considered treatments of choice, followed by other therapies yet to be thoroughly studied, including the role of the low-histamine diet, corticosteroids, and treatment of associated IBS symptoms. Given that both eosinophils and mast cells may have joint pathophysiologic roles, they have the potential to be a combined target for therapeutic intervention in disease states exhibiting eosinophil or mast cell involvement.

[Systemic mastocytosis with refractory ascites successfully treated with interferon-α and a leukotriene receptor antagonist]

A 67-year-old male was referred to our hospital because of anemia, thrombocytopenia, and massive ascites. A diagnosis of systemic mastocytosis was made based on the observation of many mast cells in his bone marrow, elevated serum tryptase levels, and the presence of c-kit point mutation Asp816Val. Dasatinib and cladribine were ineffective, and a large volume of ascites was removed approximately every 3 days. Then, following an asthma attack, the patient was treated with pranlukast, a leukotriene receptor antagonist (LTRA). After LTRA treatment initiation, the frequency of ascites drainage decreased, and no puncture was necessary from the 10th day after the start of LTRA. Interferon α (IFN-α) was administered from the 15th day after the start of LTRA. Thereafter, his anemia and thrombocytopenia gradually improved, the ascites disappeared, the mast cells in his bone marrow were significantly reduced, and the Asp816Val mutation disappeared. Because persistent monocytosis was evident, he was suspected of chronic myelomonocytic leukemia but has not been diagnosed and is undergoing watchful waiting. This was considered to be a rare case of refractory ascites in which IFN-α was effective and LTRA might have been beneficial.

Magnetic resonance imaging reveals distinct bone marrow patterns in indolent and advanced systemic mastocytosis

Systemic mastocytosis (SM) is broadly subcategorized according to mast cell (MC) burden and organ involvement into indolent (ISM), smoldering (SSM), and advanced SM (AdvSM). However, the pattern and extent of bone involvement remains controversial. In this institutional review board (IRB)-approved study, 115 patients with different forms of SM (ISM (n = 37, 32%), SSM (n = 9, 8%), and AdvSM (n = 69, 60%)) underwent a whole-body magnetic resonance imaging including sagittal and coronal T1 and turbo inversion recovery magnitude (TIRM) sequences of the spine. The evaluation included the pattern and extent of pathologic bone marrow (BM) signals in the spine and extremities, osteolytic lesions, and vertebral fractures. A pathologic BM pattern was observed in 4/37 (11%), 8/9 (89%), and 66/69 (96%); affection of the appendicular skeleton in 3/37 (8%), 8/9 (89%), and 67/69 (97%); and vertebral fractures in 7/37 (19%), 0/9, and 13/69 (19%) patients with ISM, SSM, and AdvSM, respectively. In AdvSM, pathologic BM pattern included activated (62%), diffuse sclerotic (25%), and small-spotted BM (9%), respectively. Only activated/sclerotic BM was associated with significantly higher MC burden, organ damage, and inferior median survival (2.9 years, p = 0.04). Vertebral fractures resembled classical multi-segmental osteoporotic fractures in ISM but not in AdvSM in which they were only found in activated/sclerotic BM. Only one patient with AdvSM had a focal osteolytic lesion in the femur. Activated/sclerotic BM changes of the spine and affection of the appendicular skeleton are indicative for SSM or AdvSM. Osteolytic lesions, which are very rare, and osteoporotic fractures are ineligible for the diagnosis of AdvSM.

Novel treatment strategies for myeloproliferative neoplasms

Although the Janus kinase (JAK) inhibitor ruxolitinib has long been the only drug licensed for treatment of the classic Philadelphia chromosome negative (Ph^-) myeloproliferative neoplasms, years of drug development efforts have begun to bear fruit with the recent approval of a novel monopegylated interferon alfa-2b, ropeginterferon alfa, for patients with polycythemia vera without symptomatic splenomegaly in Europe. Several newer JAK inhibitors (fedratinib, pacritinib, momelotinib) have shown activity in phase 3 trials in patients with myelofibrosis but have, for various reasons, not yet received regulatory approval; all these agents, however, remain in active clinical development. Many other agents with diverse mechanisms of action are being explored in clinical trials in patients with myelofibrosis, both as single agents and in combination with ruxolitinib. Besides splenomegaly and symptoms, improvement of anemia has become a new focus of drug development in myelofibrosis. Ruxolitinib appears promising also in chronic neutrophilic leukemia, where mutations in CSF3R are common. Pemigatinib, a potent and selective inhibitor of fibroblast growth factor receptor (FGFR), has shown impressive efficacy in a small registration-directed trial in patients with FGFR1-rearranged myeloid/lymphoid neoplasms. Finally, avapritinib, a highly potent and selective inhibitor of KIT^D816V, has demonstrated unprecedented response rates in patients with advanced systemic mastocytosis.

Mast Cell Leukemia with Ascites and Multiple Organs Damage

Mast Cell Leukemia (MCL), a rare subtype of systemic mastocytosis is defined by bone marrow involvement as atypical and aleukemic mast cells, if more than 20% and less than 10% of peripheral WBCs are mast cells, respectively.

We met a case of aleukemic MCL presenting with anemia and ascites for 2 years, referred for BM evaluation, suspicious of leukemia. Our findings included BM involvement by diffused aggregates of oval- and spindle-shaped atypical mast cells, lacking mature mast cells and other hematopoietic cells. The mast cells were absent in peripheral blood smear. Further assessments showed positive reaction of mast cells metachromatic granules with Tryptase, Giemsa and Toluidine blue stains, the expression of CD117/KIT and CD45 by immunohistochemistery, and elevated level of serum Tryptase.

Radiologic investigations revealed generalized lymphadenopathy, and massive hepatosplenomegaly, followed by the cervical lymphadenectomy, and liver wedge biopsy. Suspicious peritoneal lesions were identified and underwent excisional biopsy. Microscopic evaluations showed lymph nodes and liver involvement by cancer cells and the same features in peritoneal seeding. Multiple organs damage progressed in few months and the patient died despite surgery and chemotherapy.

In conclusion, we report an extremely rare case of aleukemic MCL with multiple organs damage such as liver, peritoneum, spleen, gastrointestinal tract and BM, presenting by ascites. According to this case and previous parallel studies, we suggest some clinicopathologic features in favor of poor prognosis, including the presence of multiple organs damage, hepatomegaly, ascites, peritoneal seeding, the absence of mature mast cells and other hematopoietic cells in the BM, and elevated serum Tryptase level.

[Acute myeloid leukemia evolving from KIT D816-mutated systemic mastocytosis relapsing two months after completion of chemotherapy]

Here, we report the case of a 9-year-old girl with acute myeloid leukemia (AML) developed from systemic mastocytosis (SM). She experienced bladder and rectal disturbance due to an extramedullary nodule in the paraspinal region of the sacrum. Cytogenetic and genetic analyses of leukemic cells revealed the KIT D816Y mutation besides t (8;21) (q22:q22) /RUNX1-RUNX1T1. Despite receiving proton beam therapy after conventional chemotherapy, the patient relapsed after 2 months. As SM-AML with the KIT D816 mutation in adults exhibits a poor prognosis, hematopoietic stem cell transplantation is recommended. Owing to a few reports of SM-AML in children, the standard therapy for pediatric cases has not been established to date. Based on our experience and the related literature, the prognosis of childhood SM-AML could be as poor as in adults. Hence, further investigation, including mutational analyses of the KIT gene, is warranted to establish a risk-oriented strategy for managing childhood SM-AML.

Indolent systemic mastocytosis mimicking Crohn's disease

Mastocytosis is a rare and heterogeneous group of diseases whose common element is the presence of dense mast-cell infiltrates in various tissues. The gastrointestinal (GI) tract is frequently affected with vague and subtle manifestations, making the diagnosis of GI mastocytosis rather formidable and challenging. The diagnosis of the disease requires a high level of clinical suspicion and an index of familiarity. To our knowledge, this is the first case of indolent systemic mastocytosis with colonic ulcerations. Because of the unusual presentation of mastocytosis, it was initially misdiagnosed as Crohn’s disease; the diagnosis of mastocytosis was established after further evaluation of the patient’s history and further investigation. Systemic mastocytosis should therefore be considered in the differential diagnosis in patients presenting with abdominal manifestations that cannot be otherwise explained or attributed to common GI pathologies and in cases where the patient’s trajectory does not follow the expected course. More research is needed into the epidemiology and the non-classical presentation of systemic mastocytosis in order to increase awareness of the disease in the medical community.

Mastocytosis: One Word for Different Diseases

Mastocytosis is a neoplastic disease originating from tissue infiltration by transformed mast cells. The diagnosis requires a high grade of suspicion due to the large variety of presenting symptoms. The World Health Organization classification recognizes localized (cutaneous) and systemic forms of the disease, with these forms showing different degrees of aggressiveness. Mastocytosis is often a multiorgan disease, and its correct management requires a multidisciplinary team of experienced consultants to provide overall patient care. Bone marrow evaluation by molecular analyses, skeleton X-ray and abdominal scan together with allergologic and dermatologic evaluation constitute the essential diagnostic work-up for adult patients with mastocytosis. As clinical situations vary, treatment options range from the use of drugs to treat the symptoms, such as anti-H1 receptors and steroids, to UV irradiation, which is overwhelmingly used in patients with cutaneous mastocytosis (CM) or indolent systemic mastocytosis, to cytoreductive treatment to control life-threatening symptoms or organ damage in the more aggressive forms of the disease. Prognosis also widely differs among patients diagnosed with mastocytosis, with the spectrum ranging from an almost normal life expectancy for those with CM and to less than 1-year median overall survival for those with mast cell leukemia.