Diffuse cutaneous mastocytosis responding to cyproheptadine

Diffuse Cutaneous Mastocytosis: A Current Understanding of a Rare Disease

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

When Mast Cells Run Amok: A Comprehensive Review and Case Study on Severe Neonatal Diffuse Cutaneous Mastocytosis

Neonatal diffuse cutaneous mastocytosis (NDCM) is defined as the infiltration of the epidermis by a clonal proliferation of mast cells, observed at birth, without initial signs of systemic involvement. The typical driver mutation is in the KIT gene. We report a rare case of a boy, born at term, already presenting at birth with generalized subcutaneous nodules on the face, scalp, trunk, back, hands, and feet. The spleen, liver, and inflammatory markers were normal at birth. Tryptase was significantly elevated. A bone marrow biopsy showed no mast cell involvement at age 2 months. A punch biopsy at age 2 months revealed CD117-positive cells diffusely infiltrating the skin, with subsequent DNA NGS sequencing for the formalin-fixed paraffin embedded tissue (FFPE) identifying the pathogenic NM_000222.3:c.1504_1509dup; p.(Ala502_Tyr503dup) variant in the KIT gene previously associated with cutaneous mastocytosis. At 2 years follow-up, he had splenomegaly and multiple cervical and inguinal adenopathy, while the skin nodules persisted, especially on the scalp with accompanying pruritus. He received oral and local sodium cromoglycate, oral antihistamines, antibiotic cream for skin infection, and iron supplementation; however, compliance to treatment was relatively low. The prognosis is difficult to predict, as he developed systemic involvement, failure to thrive, and mild psychomotor delay. A case aggregation of NDCM reported in the literature was performed to provide a comprehensive overview of this rare pathology, to better understand the prognosis. NDCM is a life-threatening disease with severe complications. Almost half had severe complications, such as mast hepatosplenomegaly, adenopathy, bacterial infections, mast cell leukaemia, and systemic involvement.

Pharmacotherapy of mast cell disorders

PURPOSE OF REVIEW

Mast cell disorders (MCDs) comprise mastocytosis and disorders referred to as mast cell activation syndrome and are caused by abnormal accumulation and/or activation of mast cells in tissues. Clinical signs and symptoms are protean; therefore, finding suitable treatment options for individual patients entails a challenge for clinicians. The purpose of this manuscript is to review the literature on the available therapeutic interventions in patients with MCD.

RECENT FINDINGS

Pharmacotherapy is mainly directed against the effects of mast cells and their mediators. The current recommendations are exclusively based on expert opinions due to the lack of controlled clinical trials. The targeted therapies aiming at blocking mutant KIT variants and/or downstream signaling pathways are currently being developed and may be considered in severely affected, therapy-refractory patients.

SUMMARY

There is currently no method for predicting the best available approach to control symptoms in individual patients with MCD. Therefore, a stepwise, individual-based approach in pharmacotherapy options appears to be most successful strategy and is recommended in all patients. The core component of the treatment in most patients is to control symptoms caused by mast cell mediator release, whereas cytoreductive therapies are mainly reserved for patients with advanced/aggressive systemic mastocytosis.

Neonatal onset diffuse cutaneous mastocytosis: a case report and review of the literature

Diffuse cutaneous mastocytosis is a rare variant of mast cell disease with widespread erythroderma, which is normally clinically apparent in early infancy. We report the case of a neonate who presented with diffuse erythrodermic rash and bullous lesions. Biopsy specimens showed a dense dermal infiltrate of mast cells. Serum histamine and tryptase levels were elevated. No somatic mutation of the c-kit gene was found. Blistering ceased at 5 months of age, but atopic dermatitis appeared at 6 months and allergic workup revealed a high level of food-specific IgE. Herein, we describe the case and provide the first review of the literature on neonatal onset diffuse cutaneous mastocytosis to clarify the prognosis of this condition.

Regulation of mast cell responses in health and disease

Mast cells are multifunctional cells that initiate not only IgE-dependent allergic diseases but also play a fundamental role in innate and adaptive immune responses to microbial infection. They are also thought to play a role in angiogenesis, tissue remodeling, wound healing, and tumor repression or growth. The broad scope of these physiologic and pathologic roles illustrates the flexible nature of mast cells, which is enabled in part by their phenotypic adaptability to different tissue microenvironments and their ability to generate and release a diverse array of bioactive mediators in response to multiple types of cell-surface and cytosolic receptors. There is increasing evidence from studies in cell cultures that release of these mediators can be selectively modulated depending on the types or groups of receptors activated. The intent of this review is to foster interest in the interplay among mast cell receptors to help understand the underlying mechanisms for each of the immunological and non-immunological functions attributed to mast cells. The second intent of this review is to assess the pathophysiologic roles of mast cells and their products in health and disease. Although mast cells have a sufficient repertoire of bioactive mediators to mount effective innate and adaptive defense mechanisms against invading microorganisms, these same mediators can adversely affect surrounding tissues in the host, resulting in autoimmune disease as well as allergic disorders.

Urticária pigmentosa em adulto com apresentação clínica exuberante

A mastocitose é afecção rara e heterogênea, caracterizada por aumento da densidade dos mastócitos na pele e em outros órgãos, para a qual não há tratamento específico. Descreve-se um caso de urticária pigmentosa em paciente adulta com quadro clínico exuberante.

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.

Beyond chronic myelogenous leukemia

The myeloproliferative disorders (MPDs) are chronic malignant conditions originating from the clonal expansion of a multipotential hematopoietic stem cell. These diseases include polycythemia vera (PV), essential thrombocythenia, atypical chronic myeloid leukemia, idiopathic hypereosinophilic syndrome (HES), agnogenic myeloid metaplasia with myelofibrosis, and others. Receptor tyrosine kinases-the platelet-derived growth factor receptors (PDGFRs) and c-Kit-and their respective ligands have been implicated in the pathogenesis of MPDs. For example, a constitutively activated PDGFR fusion tyrosine kinase (FIP1L1-PDGFRA) was identified in some patients with HES, a disease characterized by sustained overproduction of eosinophils that has been classified by the World Health Organization as a chronic subtype of the MPDs. Imatinib is a selective inhibitor of PDGFRs, c-Kit, Abl and Arg protein-tyrosine kinases, as well as Bcr-Abl, the oncogenic tyrosine kinase that causes chronic myeloid leukemia. The efficacy of imatinib in treating HES, systemic mast cell disease, chronic myelomonocytic leukemia associated with PDGFRbeta fusion genes, and (to a lesser extent) PV and idiopathic myelofibrosis was reviewed from institutional experience and a review of the literature. In 3 studies that involved 11 patients with PV, 10 patients had reductions in phlebotomy with imatinib. Eight studies of 42 patients with HES indicated that 70% achieved complete hematologic remissions with imatinib. Four studies of 6 patients with MPD indicated responses with imatinib in 5 patients. Insight into the molecular pathogenesis of MPDs will improve the definitions of different disease categories and suggests that signal transduction inhibition is likely to be an increasingly important treatment option in the future.

Mastocytosis and the skin

The most frequent site of organ involvement in individuals with any form of mastocytosis is the skin. Cutaneous lesions include urticaria pigmentosa, mastocytoma, diffuse and erythematous cutaneous mastocytosis, and telangiectasia macularis eruptiva perstans. The major histologic feature is an increase in the number of mast cells in the dermis. Treatment depends on the type of skin lesions.

Treatment of systemic mast cell disorders

The heterogeneous nature of disease manifestations in mastocytosis requires the individualization of therapy to each patient's clinical presentation and prognosis. The mainstay of treatment for most categories of mastocytosis are H1 and H2 antihistamines with the addition of corticosteroids for more severe symptoms. This article presents a summary of treatment strategies for indolent and aggressive forms of mastocytosis along with a discussion of future therapeutic directions.