Mastocytosis and the skin

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.

Diagnosis and treatment of systemic mastocytosis in Brazil: Recommendations of a multidisciplinary expert panel

Introduction: Systemic Mastocytosis comprises a group of neoplastic diseases characterized by clonal expansion and infiltration of mast cells into several organs. The diagnosis and treatment of this disease may be challenging for non-specialists. Objective: Make suggestions or recommendations in Systemic Mastocytosis based in a panel of Brazilian specialists.

Method and results: An online expert panel with 18 multidisciplinary specialists was convened to propose recommendations on the diagnosis and treatment of Systemic Mastocytosis in Brazil. Recommendations were based on discussions of topics and multiple-choice questions and were graded using the Oxford Centre for Evidence-Based Medicine 2011 Levels of Evidence Chart.

Conclusion: Twenty-two recommendations or suggestions were proposed based on a literature review and graded according to the findings.

Mast Cell Activation Disorders

Background and Objectives: Mast cell disorders comprise a wide spectrum of syndromes caused by mast cells' degranulation with acute or chronic clinical manifestations. Materials and Methods: In this review article we reviewed the latest findings in scientific papers about mast cell disorders with a particular focus on mast cell activation syndrome and mastocytosis in pediatric age. Results: Patients with mast cell activation syndrome have a normal number of mast cells that are hyperreactive upon stimulation of various triggers. We tried to emphasize the diagnostic criteria, differential diagnosis, and therapeutic strategies. Another primary mast cell disorder is mastocytosis, a condition with a long-known disease, in which patients have an increased number of mast cells that accumulate in different regions of the body with different clinical evolution in pediatric age. Conclusions: Mast cell activation syndrome overlaps with different clinical entities. No consensus was found on biomarkers and no clearly resolutive treatment is available. Therefore, a more detailed knowledge of this syndrome is of fundamental importance for a correct diagnosis and effective therapy.

Mast cell activation in the context of elevated basal serum tryptase: genetics and presentations

PURPOSE OF REVIEW

To describe inherited and acquired genetic variants and clinical entities associated with increased basal serum tryptase (BST), distinguish these levels from those which acutely rise due to mast cell activation, and finally to characterize the association between chronically elevated basal serum tryptase and episodic mast cell activation.

RECENT FINDINGS

Hereditary alpha-tryptasemia is a commonly inherited genetic cause for basally elevated serum tryptase and explains elevated BST in many individuals who do not have evidence of clonal myeloid or mast cell disease. When clonal myeloid disease is present, BST may be elevated and can be a biomarker of a number of disparate disorders of the myeloid compartment. Elevated BST is most commonly caused by hereditary alpha tryptasemia but may also be indicative of clonal myeloid disease. Clinical reports suggest that elevated BST is associated with increased risk for more severe systemic allergic reactions to a number of eliciting agents and exposures. Additional studies are needed to determine the role that inherited or acquired genetic variants associated with elevated BST and clonal or non-clonal myeloid diseases may play in these reactions.

Targeted Treatment Options in Mastocytosis

Mastocytosis refers to a heterogeneous group of disorders resulting from the clonal proliferation of abnormal mast cells and their accumulation in the skin (cutaneous mastocytosis when only in the skin, CM) or in various organs (systemic mastocytosis, SM). This leads to a wide variety of clinical manifestations resulting from excessive mediator release in CM and benign forms of SM (indolent SM, ISM) and from tissue mast cell infiltration causing multiorgan dysfunction and failure in more aggressive subtypes (aggressive SM, ASM, or mast cell leukemia). In addition, SM may be associated with hematological neoplasms (AHN). While treatment of ISM primarily aims at symptom management with anti-mediator therapies, cytoreductive and targeted therapies are needed to control the expansion of neoplastic mast cells in advanced forms of SM, in order to improve overall survival. Mast cell accumulation results from a gain-of-function mutation (mostly the D816V mutation) within the KIT tyrosine kinase domain expressed by mast cells and additional genetic and epigenetic mutations may further determine the features of the disease (ASM and AHN). Consequently, tyrosine kinase inhibitors and targeted therapies directed against the oncogenic signaling machinery downstream of KIT are attractive therapeutic approaches. A better understanding of the relative contribution of these genetic and epigenetic events to the molecular pathogenesis of mastocytosis is of particular interest for the development of targeted therapies and therefore to better choose patient subgroups that would best benefit from a given therapeutic strategy.

Clinical features of mastocytosis at pediatric patients

Mastocytosis is relevant to heterogeneous disease group characterized with redundant accumulation and proliferation of mast cells in tissues. The skin form of mastocytosis is mainly occurs in children. The article contains the current data on etiology, pathogenesis, classification, clinical forms, diagnosis, prophylactics and mastocytosis treatment at children.

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.

Systemic Mastocytosis: Clinical Update and Future Directions

Systemic mastocytosis (SM) is defined as the accumulation of abnormal mast cells (MC) in 1 or more extracutaneous tissues. Symptoms are due to either MC activation or organ infiltration and vary depending on disease subtype. More benign forms of SM, such as indolent SM, result in a life expectancy similar to the general population, while more aggressive subtypes, such as MC leukemia (MCL), have a median survival measured on the order of months. Treatment of indolent SM is directed at controlling the symptoms associated with MC activation. In advanced forms, such as aggressive SM and MCL, agents targeting MC proliferation such as KIT tyrosine kinase inhibitors, cladribine, and thalidomide may be provided. Newer agents based on preclinical rationale are also being actively investigated. However, the only potentially curative therapy for aggressive SM/MCL remains hematopoietic stem cell transplantation. Given that SM is a relatively rare disease, clinicians are often underprepared to evaluate, diagnose, and effectively treat this clinically heterogeneous condition. Here we seek to familiarize clinicians with this orphan disease and review current and future treatment approaches.

Symptomatic response to imatinib mesylate in cutaneous mastocytosis associated with chronic myelomonocytic leukemia

Mastocytosis is an uncommon disorder defined by increased and abnormal mast cells in one or more tissues. Cutaneous mastocytosis (cm) is limited to the skin, with varying degrees of rash, pruritus, and disfigurement. Systemic mastocytosis (sm) typically involves the bone marrow, sometimes in association with other bone marrow disorders, including chronic myelomonocytic leukemia (cmml). Mastocytosis has been associated with somatic mutations in the gene encoding the tyrosine kinase Kit, leading to identification of Kit as a therapeutic target. The Kit inhibitor imatinib mesylate is approved for aggressive sm. We present an unusual patient with disabling pruritus from telangiectasia macularis eruptiva perstans, a subtype of cm, and cmml, but with no evidence of systemic mast cell disease. She was treated with imatinib and experienced marked improvement in her pruritus. Concomitant cm and cmml have not previously been reported, and the present report is the first of successful imatinib therapy in an adult patient with cm.

Death from mast cell leukemia: a young patient with longstanding cutaneous mastocytosis evolving into fatal mast cell leukemia

   Mastocytosis is a broad term used for a group of disorders characterized by accumulation of mast cells in the skin with or without extracutaneous involvement. The clinical spectrum of the disease varies from only cutaneous lesions to highly aggressive systemic involvement such as mast cell leukemia. Mastocytosis can present from birth to adulthood. In children, mastocytosis is usually benign, and there is a good chance of spontaneous regression at puberty, unlike adult-onset disease, which is generally systemic and more severe. Moreover, individuals with systemic mastocytosis may be at risk of developing hematologic malignancies. We describe a girl who presented to us with a solitary mastocytoma at age 5 and later developed maculopapular cutaneous mastocytosis. At age 23, after an episode of anaphylactic shock, a bone marrow examination revealed mast cell leukemia. She ultimately died despite aggressive chemotherapy and bone marrow transplantation.

Telangiectasia macularis eruptiva perstans: more than skin deep

Systemic mastocytosis is a rare disease involving the infiltration and accumulation of active mast cells within any organ system. By far, the most common organ affected is the skin. Cutaneous manifestations of mastocytosis, including Urticaria Pigmentosa (UP), cutaneous mastocytoma or telangiectasia macularis eruptive perstans (TMEP), may indicate a more serious and potentially life-threatening underlying disease. The presence of either UP or TMEP in a patient with anaphylactic symptoms should suggest the likelihood of systemic mastocytosis, with the caveat that systemic complications are more likely to occur in patients with UP. TMEP can usually be identified by the typical morphology, but a skin biopsy is confirmative. In patients with elevated tryptase levels or those with frequent systemic manifestations, a bone marrow biopsy is essential in order to demonstrate mast cell infiltration. Further genetic testing for mutations of c-kit gene or the FIP1L1 gene may help with disease classification and/or therapeutic approaches. Rarely, TMEP has been described with malignancy, radiation therapy, and myeloproliferative disorders. A few familial cases have also been described. In this review, we discuss the clinical features, diagnosis and management of patients with TMEP. We also discuss the possible molecular pathogenesis and the role of genetics in disease classification and treatment.

Skin manifestations of hormone-secreting tumors

Endocrine and metabolic diseases, besides affecting other organs, can result in changes in cutaneous function and morphology and can lead to a complex symptomatology. Dermatologists may see some of these skin lesions first, either before the endocrinologist, or even after the internist or specialist has missed the right diagnosis. Because some skin lesions might reflect a life-threatening endocrine or metabolic disorder, identifying the underlying disorder is very important, so that patients can receive corrective rather than symptomatic treatment. In this issue, we will review various hormone-secreting tumors, including pituitary disorders (Cushing's syndrome and acromegaly), hyperthyroidism, glucagonoma, carcinoid syndrome, mastocytosis, and hyperandrogenism. We will focus on clinical manifestations, mainly cutaneous, followed by a brief discussion on how to make the diagnosis of each condition in addition to treatment options.

Anesthesia in children with mastocytosis--a case based review

INTRODUCTION

Mastocytosis is a rare heterogeneous disease of bone marrow origin which arises as a consequence of abnormal growth and/or accumulation of clonal mast cells in one or more organs. Sixty-five percent of patients with mastocytosis are children in whom it usually regresses around puberty. Adult patients with mastocytosis have been identified as at high risk of widespread mast cell degranulation in the perioperative period, this finding has not been reported in pediatric patients. This information has been repeated in mastocytosis websites where it has the potential to cause disproportionate alarm in parents.

METHODS

We considered our experience of six children with mastocytosis together with a review of the literature to examine other reports of anesthesia in children with mastocytosis. Our literature search found 57 general anesthetics in 39 children with mastocytosis. In addition, we searched for information about current consensus in diagnosis, classification and treatment of mastocytosis and in vitro and in vivo studies looking at mast cell behavior in response to drugs commonly used during anesthesia.

DISCUSSION

The literature search revealed that general anesthesia has precipitated life threatening complications in adult patients with systemic mastocytosis (SM) but no such complications have been described in children with mastocytosis. Our own experience with children with mastocytosis is of uneventful anesthesia. Advances in the understanding of the genetic basis of mastocytosis suggest that pediatric cutaneous mastocytosis (CM) and SM are different entities. SM in children is extremely rare and is associated with elevated baseline serum tryptase. There are few reports of anesthesia in this group.

CONCLUSION

The risks for most pediatric patients are overstated by mastocytosis websites. Most pediatric patients with CM do not appear to be at risk of widespread mast cell degranulation during anesthesia but because of the small number of cases reported, the risk cannot be ascertained with confidence. Children with SM and a high baseline serum tryptase (marker of mast cell burden) may merit extra precautions but experience in this subgroup is even more limited. Drugs which cause minimal histamine release can be selected from the range of drugs available in most pediatric centers without compromise to technique.

Gastrointestinal manifestations of dermatologic disorders

The skin and the gastrointestinal tract may be affected concurrently by the same diseases. Pathogenetically, these conditions may be primarily dermatologic diseases involving the gastrointestinal (GI) tract or systemic diseases involving the skin, GI tract, and liver simultaneously. The correct diagnosis of such conditions relies on the ability of the gastroenterologist to recognize the underlying dermatologic disorder. The goal of this clinical review article is to increase gastroenterologists' awareness and understanding of some of these conditions. Case vignettes are presented and the relevant literature reviewed for epidermolysis bullosa, mastocytosis, hereditary hemorrhagic telangiectasia, and melanoma. This review focuses on increasing gastroenterologists' ability to recognize, diagnose, comprehend, and manage patients with these dermatologic conditions who have GI manifestations. Advances in molecular genetics that provide insight into the underlying pathophysiology and histopathology of these lesions are highlighted.

Systemic mastocytosis: a concise clinical and laboratory review

CONTEXT

Systemic mastocytosis is characterized by abnormal growth and accumulation of neoplastic mast cells in various organs. The clinical presentation is varied and may include skin rash, symptoms related to release of mast cell mediators, and/or organopathy from involvement of bone, liver, spleen, bowel, or bone marrow.

OBJECTIVE

To concisely review pathogenesis, disease classification, clinical features, diagnosis, and treatment of mast cell disorders.

DATA SOURCES

Pertinent literature emerging during the last 20 years in the field of mast cell disorders.

CONCLUSIONS

The cornerstone of diagnosis is careful bone marrow histologic examination with appropriate immunohistochemical studies. Ancillary tests such as mast cell immunophenotyping, cytogenetic/molecular studies, and serum tryptase levels assist in confirming the diagnosis. Patients with cutaneous disease or with low systemic mast cell burden are generally managed symptomatically. In the patients requiring mast cell cytoreductive therapy, treatment decisions are increasingly being guided by results of molecular studies. Most patients carry the kit D816V mutation and are predicted to be resistant to imatinib mesylate (Gleevec) therapy. In contrast, patients carrying the FIP1L1-PDGFRA mutation achieve complete responses with low-dose imatinib therapy. Other therapeutic options include use of interferon-alpha, chemotherapy (2-chlorodeoxyadenosine), or novel small molecule tyrosine kinase inhibitors currently in clinical trials.

Unusual cutaneous findings of urticaria pigmentosa and telangiectasia macularis eruptiva perstans associated with marked myelofibrosis

Mastocytosis is a heterogeneous group of disorders characterized by mast cell hyperplasia in the bone marrow, liver, spleen, lymph nodes, gastrointestinal tract, and skin. We present a patient with malignant mastocytosis of 11 years' duration. This case highlights the cutaneous findings of mastocytosis with systemic involvement, yet the patient maintains a relatively normal lifestyle with only minimal discomfort and only borderline normochromic anemia. Thus his course is not truly that of malignant mastocytosis but of indolent systemic mastocytosis with cutaneous findings of telangiectasia macularis eruptiva perstans (TMEP).

Pathogenesis, clinical features, and treatment advances in mastocytosis

Systemic mastocytosis (SM) is characterized by the abnormal growth and accumulation of mast cells (MC) in one or more organs. The interaction between the cytokine stem cell factor (SCF) and its cognate receptor, the c-kit receptor tyrosine kinase (KIT), plays a central role in regulating MC growth and differentiation. Whereas germline and somatically acquired activating mutations of KIT have been identified in SM, the issue as to whether individual KIT mutation(s) are necessary and sufficient to cause MC transformation remains unclear based on currently available data. Activating mutations of platelet-derived growth factor receptor-alpha (FIP1 L1-PDGFRA) are identified in a significant number of SM cases that have associated eosinophilia. To date, as with gastrointestinal stromal tumors, activating mutations of KIT and PDGFRA appear to be alternative and mutually exclusive genetic events in SM. The World Health Organization has specified criteria for classification of SM into six major subtypes: cutaneous mastocytosis, indolent systemic mastocytosis (ISM), systemic mastocytosis with an associated clonal hematological non-mast-cell disorder (SM-AHNMD), aggressive systemic mastocytosis (ASM), mast cell leukemia, and mast cell sarcoma. The ability to molecularly classify individual SM cases based on the presence or absence of specific mutations allows for molecularly targeted therapy in a growing number of cases. Imatinib mesylate therapy might result in complete remission of SM cases with wild-type KIT, certain KIT mutations, such as F522C, or the FIP1L1-PDGFRA fusion gene, but not of D816V-KIT-bearing SM. For the latter, interferon-alpha and 2-CdA are potential first- and second-line therapeutic options. Other drugs under investigation include novel tyrosine kinase inhibitors, as well as NF-kappaB inhibitors, which might display greater selectivity towards D816V-KIT as compared to wild type KIT. The pathogenesis of mastocytosis, its major clinical subtypes, and recent treatment advances are discussed in this chapter.

Systemic Mastocytosis: Clinical Manifestations and Differential Diagnosis

Mast cells produce symptoms by local and remote effects of mediator release and by their presence in increased numbers in normal tissue and bone marrow, where they damage and impair normal organ function. Moreover, mast cells are long-lived and heterogeneous in their response to secretagogues and to inhibitors of mediator release. Clinicians sorting out the diagnosis of SM on the basis of presenting signs and symptoms continue to have their diagnostic skills challenged because of the rarity of this disorder, the fact that many symptoms of SM are present in more common disorders, and the multiple guises that SM may assume at the time of presentation.

Rare syndromes

Dermatologists may also encounter patients presenting with skin lesions that reflect an underlying endocrine disorder not commonly seen in daily practice. Some of these endocrine disorders include glucagonoma, neurofibromatosis type 1, McCune-Albright syndrome, multiple endocrine neoplasia, the Carney complex, carcinoid tumors, and mastocytosis. The clinical syndrome classically associated with glucagonoma includes necrolytic migratory erythema, weight loss, diabetes mellitus, anemia, cheilitis, venous thrombosis, and neuropsychiatric symptoms. The hallmarks of neurofibromatosis type 1 are the multiple café-au-lait spots and associated cutaneous neurofibromas. Other presenting features include freckling, peripheral neurofibromas, Lisch nodules, bone abnormalities, tumors, neurologic abnormalities and hypertension. McCune-Albright syndrome is characterized by café-au-lait spots, polyostotic fibrous dysplasia, sexual precocity, and hyperfunction of multiple endocrine glands. Multiple endocrine neoplasia type 2A is characterized by medullary thyroid cancer, pheochromocytoma, and primary parathyroid hyperplasia. In some patients with multiple endocrine neoplasia type 2A, cutaneous lichen amyloidosis may also be present. Multiple endocrine neoplasia type 2B is characterized by medullary thyroid cancer and pheochromocytoma but not hyperparathyroidism. The syndrome also includes mucosal neuromas, typically involving the lips and tongue, intestinal ganglioneuromas and a marfanoid habitus. Multiple endocrine neoplasia type 1 is an autosomal dominant predisposition to tumors of the parathyroid glands (four-gland hyperplasia), anterior pituitary, and pancreatic islet cells; hence, the mnemonic device of the "3 Ps"; multiple cutaneous lesions (angiofibromas and collagenomas) are frequent in patients with multiple endocrine neoplasia type 1. Carney complex may be viewed as a form of multiple endocrine neoplasia because affected patients often have tumors of two or more endocrine glands, including primary pigmented nodular adrenocortical disease (some with Cushing's syndrome), pituitary adenoma, testicular neoplasms, thyroid adenoma or carcinoma, and ovarian cysts. Additional unusual manifestations include psammomatous melanotic schwannoma, breast ductal adenoma, and a rare bone tumor, osteochondromyxoma. Carcinoid syndrome is the term applied to a constellation of symptoms mediated by various humoral factors elaborated by some carcinoid tumors; the major manifestations are diarrhea, flushing, bronchospasm, and cardiac valvular lesions. Mast cell diseases include all disorders of mast cell proliferation. These diseases can be limited to the skin, referred to as "cutaneous mastocytosis," or involve extracutaneous tissues, called "systemic mastocytosis." Patients present with urticaria pigmentosa, mastocytoma, or diffuse cutaneous mastocytosis. Systemic involvement may be gastronintestinal, hematologic, neurologic, and skeletal.

Shortness of Breath, Syncope, and Cardiac Arrest Caused by Systemic Mastocytosis

During a 3-month period, a 33-year-old man presented to the emergency department on 4 occasions with dyspnea, palpitations, and syncope. His initial presentation was accompanied by acute myocardial injury and ventricular fibrillation. An extensive evaluation spanned the 3 months and included echocardiography, cardiac catheterization, electrophysiology study, tilt-table evaluation, pulmonary angiography, electroencephalography, and serum and urine analysis. Diagnosis eluded clinicians until a rash was recognized to be urticaria pigmentosa, and biopsy of the rash then implicated mastocytosis. Since the initiation of pharmacotherapy nearly 5 years ago, the patient has remained asymptomatic. This case demonstrates that systemic mastocytosis can present as recurrent syncope and even as cardiac arrest. Diagnosis of this rare but potentially fatal disease is made particularly challenging by its protean manifestations.

Mastocytosis and Hymenoptera allergy

PURPOSE OF REVIEW

Mastocytosis is a rare disease with associations with anaphylactic reactions to Hymenoptera stings. The purpose of this review is to examine these associations with regard to prevalence, diagnosis, treatment and prognosis in the insect-venom-allergic population.

RECENT FINDINGS

Systemic mastocytosis is overrepresented in the Hymenoptera-allergic population and is associated with an increased risk of more-severe reactions following field stings or sting challenges, lack of sensitization to venoms by skin test or radioallergosorbent test, increased side effects to venom immunotherapy, reduced efficacy of venom immunotherapy and treatment failures. Serum tryptase determinations are a simple and reliable screening procedure for systemic mastocytosis. Patients with elevated values should be referred to specialized centers for confirmatory diagnosis including bone marrow histology.

SUMMARY

The diagnosis of systemic mastocytosis should be considered in Hymenoptera-allergic patients showing any of the management problems associated with this disease. Patients with mastocytosis and Hymenoptera allergy require special attention, mainly because of reduced safety and efficacy of venom immunotherapy. Whether or not venom immunotherapy is given, such patients should continue to carry an Epipen indefinitely.

Management of patients with systemic mastocytosis: review of M. D. Anderson Cancer Center experience

Mastocytosis is characterized by mast cell proliferation that may be limited to the skin (cutaneous mastocytosis) or may involve one or more extracutaneous organs, e.g., the bone marrow (systemic mastocytosis; SM). This study objective is to evaluate the features and outcome of patients referred to M. D. Anderson Cancer Center (MDACC) with SM. A search of the MDACC database from 1944 to 2002 was conducted for patients with SM and review of their clinical charts. Eighteen patients with mastocytosis were identified in the MDACC database; 15 (11 males and 4 females) had SM and available information. Two had associated myelodysplastic syndrome (MDS), and one had acute myeloid leukemia (AML). The median age was 58 years (range 31-80). Nine patients were treated with subcutaneous interferon-alpha, and only 1 experienced temporary control of the disease. Three of these patients were then treated with imatinib mesylate: transient improvement was noted in two patients. One patient underwent stem cell transplantation as first therapy and achieved complete remission; this patient had associated MDS and is now in complete remission for 8 years. The patient with associated AML was treated with high-dose cytarabine and idarubicin; he has been in complete remission for 16 months. One patient was treated with induction chemotherapy consisting of high-dose cytarabine and 2CDA but expired due to sepsis. Three patients received symptomatic therapy only; these were the only 3 patients who presented with normal blood counts. SM is rare and has no effective standard of care. Collaboration among academic centers to accrue enough patients to evaluate novel therapeutic strategies is needed.

[Mastocytosis: advances in molecular diagnosis and therapeutics]

Systemic mastocytosis is a rare myeloproliferative-like disease, characterized by an abnormal proliferation of mast cells in various organs. Two types of clinical manifestations can be distinguished: those related to release of mast cell mediators release and those related to tumor proliferation involving different organs, these later defining systemic mastocytosis. Until recently, treatment was mainly symptomatic, without anti tumor effect. These last years, advances have been made in the understanding of the disease with the discovery of the presence, in a number of patients, of mutations of the c-kit oncogene, coding for the receptor of the major growth factor for mast cells. These mutations induce autophosphorylation of the c-kit receptor in the absence of its ligand, the Stem Cell Factor. Based on experiences acquired in the treatment of myeloproliferative disorders, evaluation of new therapeutics, such as cladribine or interferon-alpha, is in progress. Finally, it would be possible to design, in the very next future, new tyrosine kinase inhibitors targeting specifically the mutant forms of c-Kit found in patients suffering from systemic mastocytosis.

Urticaria pigmentosa

Urticaria pigmentosa (UP), resulting from the accumulation of excessive numbers of mast cells in the skin, is the most common form of cutaneous mastocytosis. Observations highlight the diversity of this disease. Clonal expansion of early hematopoietic progenitor cells carrying activating mutations in KIT seems to be the basis of adult-onset UP. New pathogenetic findings are leading to the development of new diagnostic surrogate markers of disease and therapeutic approaches targeting neoplastic mast cells. Promising strategies may arise from an increased understanding about the cause of mastocytosis and the signaling pathways initiated by kit activation.

Scarring alopecia associated with mastocytosis

BACKGROUND

Mastocytosis is comprised of a group of heterogeneous diseases involving various organs. Urticaria pigmentosa is the most common manifestation of cutaneous mastocytosis; others include mastocytoma, diffuse mastocytosis, and telangiectasia macularis eruptiva perstans.

METHODS

We describe a case of indolent mastocytosis presenting as scarring alopecia. The scalp biopsy revealed a perifollicular and dermal inflammatory infiltrate composed predominantly of mast cells, which was confirmed by tryptase and Giemsa stains.

RESULTS

The preponderance of mast cells in the biopsy prompted testing for urine N-methylhistamine levels, which were elevated and confirmed the diagnosis of mastocytosis. This is the first report of mastocytosis presenting as scarring alopecia.

CONCLUSIONS

This case suggests that the diagnosis of mastocytosis should be entertained in patients presenting with scarring alopecia accompanied by an intense mast cell infiltrate on scalp biopsy and also supports the notion that mast cells may be involved in the pathogenesis of alopecia.

Assessment of the extent of cutaneous involvement in children and adults with mastocytosis: relationship to symptomatology, tryptase levels, and bone marrow pathology

BACKGROUND

Cutaneous involvement occurs in most patients with systemic mastocytosis.

OBJECTIVE

We sought to determine whether the extent of cutaneous involvement is predictive of systemic disease.

METHODS

In a prospective survey of 48 adults and 19 children, the extent and density of cutaneous lesions were compared with patient history, symptoms, internal organ involvement, serum total mast cell tryptase level, and bone marrow pathology.

RESULTS

Cutaneous lesions in children were of a greater mean and maximum diameter, but similar in extent and density compared with lesions in adults. In adults with skin lesions, the extent of lesions correlated to disease duration. Adults with extensive cutaneous disease experienced more pruritus and flushing. Fatigue, splenomegaly, and hepatomegaly were more frequent in adults without cutaneous involvement; and in those with a greater density of lesions and disease duration. Increased tryptase levels were found in children and adults with systemic disease and correlated to skin lesion density and bone marrow pathology.

CONCLUSION

An examination of the extent and density of cutaneous lesions in adults helps identify those with more extensive extracutaneous disease and, thus, requiring a more thorough evaluation.

Mastocytosis

Mastocytosis is defined by a pathological increase in mast cell numbers in tissues. Recent clinical observations on rare manifestations highlight the diversity of this disease. The diagnosis is now aided by new surrogate markers. At the molecular level, recent studies have reinforced the role of activating mutations in KIT in the etiology of mastocytosis. These findings provide a conceptual basis for the development for new therapeutic strategies.

Mastocytosis: review of clinical and experimental aspects

Mastcytosis is a rare disease characterized by an abnormal increase of mast cells in tissues. The skin is the organ most frequently involved, but mast cells also accumulate in the bone marrow, gastrointestinal tract, lymph nodes, spleen, and liver. Recent studies suggest that activating mutations of c-kit, a protooncogene encoding for the receptor (kit) of stem cell factor, are a possible cause of some forms of mastocytosis. In addition, an increased rate of chromosomal aberrations has been found. Despite significant advances in research on mastocytosis, curative treatment is not yet available. Current management is based on avoidance of mediator-releasing triggers and symptomatic treatment.

Mastocytosis: molecular mechanisms and clinical disease heterogeneity

Systemic mastocytosis has one unifying feature: an unexplained and pathologic increase in mast cells in specific tissues. This observation, along with clinical disease heterogeneity has long suggested that mastocytosis is a disease of complex etiology. At the same time, the last decade has witnessed significant progress in identifying the critical elements that regulate mast cell growth and development. Human mast cells are now known to arise from CD34(+) progenitors, particularly under the influence of stem cell factor (SCF). This information in turn led to the critical observation that a substantial number of patients with mastocytosis exhibit activating mutations in c-kit, the receptor for SCF. And while this observation may well be key in understanding mastocytosis, this mutation alone does not explain all heterogeneity. It now appears that other influences such as genetic polymorphisms within the host may influence the course of disease in those with KIT mutations; and that the search for additional molecular events capable of creating disease diversity must continue.