The mast cell and mast cell disease

A fully human anti-c-Kit monoclonal antibody 2G4 inhibits proliferation and degranulation of human mast cells

Given that mast cells are pivotal contributors to allergic diseases, various allergy treatments have been developed to inhibit them. Omalizumab, an anti-immunoglobulin E antibody, is a representative therapy that can alleviate allergy symptoms by inhibiting mast cell degranulation. However, omalizumab cannot reduce the proliferation and accumulation of mast cells, which is a fundamental cause of allergic diseases. c-Kit is essential for the proliferation, survival, and differentiation of mast cells. Excessive c-Kit activation triggers various mast cell diseases, such as asthma, chronic spontaneous urticaria, and mastocytosis. Herein, we generated 2G4, an anti-c-Kit antibody, to develop a therapeutic agent for mast cell diseases. The therapeutic efficacy of 2G4 antibody was evaluated in LAD2, a human mast cell line. 2G4 antibody completely inhibited c-Kit signaling by blocking the binding of stem cell factor, known as the c-Kit ligand. Inhibition of c-Kit signaling led to the suppression of proliferation, migration, and degranulation in LAD2 cells. Moreover, 2G4 antibody suppressed the secretion of pro-inflammatory cytokines, including granulocyte–macrophage colony-stimulating factor, vascular endothelial growth factor, C–C motif chemokine ligand 2, brain-derived neurotrophic factor, and complement component C5/C5a, which can exacerbate allergy symptoms. Taken together, these results suggest that 2G4 antibody has potential as a novel therapeutic agent for mast cell diseases.

The significance of CYP11A1 expression in skin physiology and pathology

CYP11A1, a member of the cytochrome P450 family, plays several key roles in the human body. It catalyzes the first and rate-limiting step in steroidogenesis, converting cholesterol to pregnenolone. Aside from the classical steroidogenic tissues such as the adrenals, gonads and placenta, CYP11A1 has also been found in the brain, gastrointestinal tract, immune systems, and finally the skin. CYP11A1 activity in the skin is regulated predominately by StAR protein and hence cholesterol levels in the mitochondria. However, UVB, UVC, CRH, ACTH, cAMP, and cytokines IL-1, IL-6 and TNFα can also regulate its expression and activity. Indeed, CYP11A1 plays several critical roles in the skin through its initiation of local steroidogenesis and specific metabolism of vitamin D, lumisterol, and 7-dehydrocholesterol. Products of these pathways regulate the protective barrier and skin immune functions in a context-dependent fashion through interactions with a number of receptors. Disturbances in CYP11A1 activity can lead to skin pathology.

Mastocytosis in Children

PURPOSE OF REVIEW

In this review, we examine the current understanding of the pathogenesis, clinical presentations, diagnostic tools, and treatment options of pediatric mastocytosis as well as the natural history of the disease.

RECENT FINDINGS

We discuss the emerging concept of mast cell activation syndrome. Mastocytosis in children presents most commonly as isolated cutaneous lesions and is a relatively rare occurrence with excellent prognosis and spontaneous regression often occurring by adolescence. Systemic mastocytosis with organ system involvement is a more serious condition and is likely to persist into adulthood.

Presentation of Telangiectasia Macularis Eruptiva Perstans as a Long-Standing Solitary Plaque Associated with Renal Carcinoma

Background:

Mastocytosis is a rare disease characterized by a primary pathological increase in mast cells in different tissues. The skin is the most frequently affected organ. Cutaneous mastocytosis, including urticaria pigmentosa, solitary mastocytoma, diffuse cutaneous mastocytosis, and telangiectasia macularis eruptiva perstans (TMEP), is usually distinguished from systemic mastocytosis. TMEP is characterized mainly by telangiectatic macules.

Objective and Methods:

We report a case of TMEP with an unusual clinical presentation as a solitary plaque of telangiectatic macules. A renal clear cell carcinoma was detected in a workup for systemic mastocytosis. We discuss the clinical and histological findings and treatment of TMEP.

Conclusions:

TMEP is a rare form of mastocytosis, which occurs mainly in adults, generally has a good prognosis, and little tendency to urticate or show constitutional symptoms. Clinicians should consider this disorder when confronted with a progressive atypical telangiectatic lesion. However, the malignant neoplasm also found in this patient is of uncertain significance.

Adult Onset of Xanthelasmoid Mastocytosis: Report of a Rare Entity

Xanthelasmoid or pseudoxanthomatous mastocytosis is an extremely rare variant of diffuse cutaneous mastocytosis. Herein, we describe an adult male with cutaneous mastocytosis showing multiple widespread yellowish ovoid papules like eruptive xanthoma. A 60-year-old male visited our outpatient clinic with a 1-year history of generalized yellowish, ovoid, and skin color papular eruption located on the trunk, groin, extremities, with the modest pruritus. Vital signs were stable, and Darier's sign was negative. No other subjective and objective signs were detected during the examination. No abnormality was detected in his diagnostic laboratory tests. Skin biopsy was taken, and histopathologic examination revealed proliferation of mast cells with ovoid and spindle nuclei with distinct cytoplasm borders around the capillaries, which was compatible with mastocytosis. Antihistamine was prescribed for pruritus control which was successful, but eruptions were persistent, and even 1-year phototherapy was not useful.

Two Cases of Telangiectasia Macularis Eruptiva Perstans Demonstrated by Immunohistochemistry for C-Kit (CD 117)

Telangiectasia macularis eruptiva perstans (TMEP) is an uncommon form of cutaneous mastocytosis that occurs exclusively in adults. Histologically, TMEP presents with scattered mast cells lined up around the dilated capillaries and venules of the superficial vascular plexus. In some cases, the number of mast cells falls within the range observed in normal skin and therefore cannot be detected by routine histologic examination. We used immunohistochemical staining for c-kit (CD 117) for the definitive diagnosis in two patients with TMEP. One of them was successfully treated with topical application of pimecrolimus.

Echinometrin: a novel mast cell degranulating peptide from the coelomic liquid of Echinometra lucunter sea urchin

Echinometra lucunter is an abundant sea urchin found in Brazilian waters. Accidents caused by this animal are common and are characterized by the penetration of the spines in the skin, which raises an inflammatory reaction through mechanical trauma as well as by the presumable action of toxins. Additionally, there have been reports of inflammatory reaction after the consumption of raw sea urchin eggs. In this work, we have isolated a peptide from E. lucunter coelomic fluid that could elicit inflammatory reactions, such as paw edema, leukocyte recruitment and diminishment of the pain threshold. This peptide was termed Echinometrin. Moreover, the peptide administration was able to produce in vivo degranulation of mouse mast cells, in a dose-response manner. The peptide was 'de novo' sequenced by mass spectrometry and its synthetic analog could reproduce all the observed effects. Sequence alignment indicates that this peptide is comprised in vitellogenin, an abundant nutrient protein present in the gametogenic cells of sea urchins, making it possible that echinometrin would be a cryptide with pro-inflammatory effects.

A concise, practical guide to diagnostic assessment for mast cell activation disease

As recognition of mast cell (MC) involvement in a range of chronic inflammatory disorders has increased, diagnosticians’ suspicions of MC activation disease (MCAD) in their chronically mysteriously inflamed patients have similarly increased. It is now understood that the various forms of systemic mastocytosis - diseases of inappropriate activation and proliferation of MCs seemingly driven by a small set of rare, usually constitutively activating mutations in assorted MC regulatory elements - comprise merely the tip of the MCAD iceberg, whereas the far larger and far more clinically heterogeneous (and thus more difficult to recognize) bulk of the iceberg consists of assorted forms of MC activation syndrome (MCAS) which manifest little to no abnormal MC proliferation and may originate from a far more heterogeneous set of MC mutations. It is reasonable to suspect MCAD when symptoms and signs of MC activation are present and no other diagnosis better accounting for the full range of findings is present. Initial laboratory assessment should include not only routine blood counts and serum chemistries but also a serum total tryptase level, which helps direct further evaluation for mastocytosis vs MCAS. Appropriate tissue examinations are needed to diagnose mastocytosis, while elevated levels of relatively specific mast cell mediators are sought to support diagnosis of MCAS. Whether assessing for mastocytosis or MCAS, testing is fraught with potential pitfalls which can easily yield false negatives leading to erroneous rejection of diagnostic consideration of MCAD in spite of a clinical history highly consistent with MCAD. Efforts at accurate diagnosis of MCAD are worthwhile, as many patients then respond well to appropriately directed therapeutic efforts.

A concise, practical guide to diagnostic assessment for mast cell activation disease

As recognition of mast cell (MC) involvement in a range of chronic inflammatory disorders has increased, diagnosticians’ suspicions of MC activation disease (MCAD) in their chronically mysteriously inflamed patients have similarly increased. It is now understood that the various forms of systemic mastocytosis - diseases of inappropriate activation and proliferation of MCs seemingly driven by a small set of rare, usually constitutively activating mutations in assorted MC regulatory elements - comprise merely the tip of the MCAD iceberg, whereas the far larger and far more clinically heterogeneous (and thus more difficult to recognize) bulk of the iceberg consists of assorted forms of MC activation syndrome (MCAS) which manifest little to no abnormal MC proliferation and may originate from a far more heterogeneous set of MC mutations. It is reasonable to suspect MCAD when symptoms and signs of MC activation are present and no other diagnosis better accounting for the full range of findings is present. Initial laboratory assessment should include not only routine blood counts and serum chemistries but also a serum total tryptase level, which helps direct further evaluation for mastocytosis vs MCAS. Appropriate tissue examinations are needed to diagnose mastocytosis, while elevated levels of relatively specific mast cell mediators are sought to support diagnosis of MCAS. Whether assessing for mastocytosis or MCAS, testing is fraught with potential pitfalls which can easily yield false negatives leading to erroneous rejection of diagnostic consideration of MCAD in spite of a clinical history highly consistent with MCAD. Efforts at accurate diagnosis of MCAD are worthwhile, as many patients then respond well to appropriately directed therapeutic efforts.

Solitary mastocytoma of the eyelid

Mastocytosis is a heterogeneous group of diseases characterized by the proliferation and abnormal infiltration of mast cells in tissue. These collections of mast cells are called mastocytomas. Solitary mastocytomas are cutaneous lesions, most commonly involving the extremities and trunk. Rubbing a cutaneous mastocytoma lesion leads to the release of histamine and other chemical mediators causing the lesion to become elevated and urticarial, similar to an allergic reaction. We describe a rare location of a presumed solitary mastocytoma of the lower eyelid in a young otherwise healthy child.

Systemic mastocytosis presenting as intraoperative anaphylaxis with atypical features: a report of two cases

Two cases of perioperative cardiovascular collapse are presented that were associated with markedly elevated mast cell tryptase levels shortly after the event, leading to the assumption that an immunoglobin E-mediated, drug-induced anaphylaxis had occurred. However, the clinical picture in both cases was atypical and subsequent skin testing failed to identify a triggering drug. Further blood tests, some weeks later, revealed persistently elevated baseline levels of mast cell tryptase. In both cases bone marrow biopsy and genetic testing confirmed the diagnosis of mastocytosis. We present evidence and speculate that mast cell degranulation was triggered by tourniquet release in the first case and by exposure to peanuts in the second. An atypical presentation of anaphylaxis should alert the anaesthetist to the possibility of previously undiagnosed mastocytosis.

Caso clínico de urticaria pigmentosa en el adulto

Objetivo: El objetivo de esta presentación de caso es mostrar el abordaje, seguimiento, tratamiento y medidas que se tomaron para un paciente adulto con urticaria pigmentosa, la cual es una enfermedad poco frecuente en la práctica diaria y que es un reto para el diagnóstico del médico general. Resultados y Conclusiones La urticaria pigmentosa es una de las formas más comunes de las mastocitosis, las cuales corresponden a una serie de procesos caracterizados por un aumento anormal de los mastocitos en diversos órganos y tejidos corporales. En la urticaria pigmentosa la manifestación es exclusiva de la piel, caracterizada por la presencia de lesiones maculopapulares de 2.5 a 5 mm de diámetro, de un color que puede oscilar entre rojo y café, distribuyéndose generalmente en tronco y extremidades respetando palmas y plantas, cerca de la mitad de los lesiones presenta rubor localizado, prurito y ampollas. Su incidencia y prevalencia son desconocidas sin embargo su aparición es más común en niños que en adultos. El diagnostico depende en gran manera de un adecuado examen físico complementado con estudios de laboratorio e histopatología. El tratamiento de elección constituye la administración de antihistamínicos orales. [Avila J, Cala J, Rodriguez J, Torres V.Urticaria pigmentosa. MedUNAB 2012; 15(1):63-67].

Diagnosis and treatment of cutaneous mastocytosis in children: practical recommendations

Cutaneous mastocytosis in children is a generally benign disease that can present at birth and is often associated with mast cell mediator-related symptoms including pruritus, flushing, and abdominal pain with diarrhea. The most common form of presentation is urticaria pigmentosa, also referred to as maculopapular mastocytosis. Flares of lesions are induced by triggers such as physical stimuli, changes in temperature, anxiety, medications, and exercise. The skin lesions are typically present on the extremities. Symptoms respond to topical and systemic anti-mediator therapy including antihistamines and cromolyn sodium. Remission at puberty is seen in a majority of cases. Progression to systemic mastocytosis with involvement of extracutaneous organs is not common. The cause of cutaneous mastocytosis is unknown and familial cases are rare. Mutations of c-kit have been observed in the skin of those affected. The diagnosis is established on clinical grounds and the findings on skin biopsy. Bone marrow studies are recommended if there is suspicion of progression of disease to an adult form, if cytoreductive therapy is contemplated, or if skin lesions remain present and/or tryptase levels remain elevated after puberty. The use of chemotherapy, including kinase inhibitors, is strongly discouraged unless severe hematologic disease is present, since malignant evolution is extremely rare.

Burning mouth syndrome and mast cell activation disorder

Burning mouth syndrome (BMS), a chronic diffuse oral pain syndrome affecting ∼1% of the general population, is diagnosed when explanatory oral pathology and other identifiable causes are absent. BMS has been recognized for decades, but its etiology remains unknown and has not previously been attributed to mast cell disease. Three cases of BMS are reported in which evidence of an underlying mast cell activation disorder (MCAD) was found; all 3 patients' oral pain responded well to MCAD-directed therapy. Mediators released from mast cells have a wide range of local and remote effects and potentially may cause the neuropathic changes and/or inflammation thought to lead to the symptoms of BMS. Mast cell disease either in oral tissue or at sites remote from the mouth should be considered in the differential diagnosis of BMS.

Mastocytosis in pregnancy

OBJECTIVE

Mastocytosis is a rare disorder characterized by abnormal accumulation of mast cells in various organs. Clinical complaints include pruritus, cutaneous flushing, dyspepsia, and episodes of anaphylaxis, and are usually the result of local and systemic mast cell mediator release. The triggers include a variety of factors including drugs, exercise, stress, anxiety, and temperature extremes.

CASE REPORT

A 26-year-old primigravida at 40 weeks' gestation with urticaria pigmentosa presented to our hospital. She was diagnosed with cutaneous mastocytosis based on pathologic examination of her skin biopsy. There were no complications during pregnancy, except for cutaneous manifestations with pruritus and premature uterine contractions at 27 weeks' gestation. After admission, antihistamine agents were administered during labor to treat the above symptoms, and antibiotic agents were given for prophylaxis of chorioamnionitis. Labor pain was successfully managed with warm showers, frequent position changes and massage, and therefore, epidural analgesia was not carried out. After 6 hours of labor, the patient gave birth to a healthy female infant via normal spontaneous vaginal delivery with right mediolateral episiotomy. Neither local anesthetic agents nor antibiotic agents caused any reaction. The postpartum period was uneventful.

CONCLUSION

Pregnant women with mastocytosis should be treated symptomatically and should avoid factors that may exacerbate symptoms of disease. Clinicians should be aware of preterm labor during pregnancy. As a preventive measure, resuscitation equipment should be available during the labor, delivery and postpartum period to treat unanticipated hypotension and shock.

Bacterial translocation to mesenteric lymph nodes increases in chronic portal hypertensive rats

PURPOSE

Bacterial translocation is a frequent complication in portal hypertension related to cirrhosis in the human clinical area. The aim of this study was to verify the existence of intestinal bacterial translocation to mesenteric lymph nodes in male Wistar rats with triple partial portal vein ligation during short- (48 h) and long-term (1 month) postoperative evolution.

RESULTS

At 48 h, ileal total aerobes bacteria (p < 0.001) and Lactobacillus decrease in sham-operated (SO) and portal hypertensive (PH) rats. At 1 month, ileal Enterococci and Streptococcus sp. show a statistically significant decrease in SO- and PH-rats. Lactobacillus decreases in the colon in SO- (p < 0.01) and in PH-rats (p < 0.001). At 1 month, colonic Enterococci decreases compared to control (p < 0.001) and SO-rats (p < 0.01). These intestinal microfloral changes are associated with bacterial translocation to mesenteric lymph nodes at 48 h (50%; p = 0.004) and 1 month (100%; p < 0.001) of postoperative evolution in PH-rats.

CONCLUSIONS

The enlargement of the stenosed portal tract related to triple partial portal vein ligation in the rat, since it increases the resistance to the portal blood flow, may be a key factor involved in one of the pathological consequences of portal hypertension, as is bacterial translocation to mesenteric lymph nodes.

[Mastocytosis. A challenge in anaesthesiology]

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

Increased angiogenesis and mast cells in the centre compared to the periphery of vitiligo lesions

The larger number of T-lymphocytes in the periphery of vitiligo lesions and their association with angiogenesis are reported. The objective of this study was to investigate angiogenesis, VEGF and mast cell in vitiligo lesions. Specimens of 30 patients' biopsies, from lesional and perilesional nondepigmented skin were stained for mast cells, CD34 and VEGF. The evaluation was made by image analysis and the measured variables were statistically analyzed. A significantly increased number of CD34 and VEGF positive vessels and mast cells were detected in the centre of the lesion than in the periphery (p < 0.0001, p < 0.0001 and p = 0.001). There was a positive correlation of CD34, VEGF and mast cell number between the centre and the periphery of the lesions (r = 0.877, p < 0.0001; r = 0.946, p < 0.0001 and r = 0.863, p < 0.0001, respectively). The increased angiogenesis and mast cell numbers in the area where lymphocyte number is lower may be explained with the stepwise inflammatory process in vitiligo.

Diffuse cutaneous mastocytosis with generalized bullae

We report on a 9-month-old female infant with multiple tense bullae and erosions covering the entire body, including the face, scalp, and trunk. The histopathological examination revealed sub-epidermal bullae with a dense dermal cellular infiltrate. The infiltrate was identified as a collection of mast cells using toluidine blue and Giemsa stains. The direct immunofluorscence was negative. A diagnosis of cutaneous diffuse mastocytosis with generalized bullae was made based on these clinical and histopathological findings. In cases with diffuse cutaneous mastocytosis with generalized bullae, systemic involvement is more frequent and more severe compared to other types of cutaneous mastocytosis. Some lethal outcomes have been reported. This is the first reported case of diffuse cutaneous mastocytosis in the Korean literature.

Cutaneous mastocytosis. Getting beneath the skin of the issue: a case report

An eleven month old girl presented with chronic urticaria since three months of age. There was a generalised hyperpigmented maculo-papular rash. Darier sign was positive. The skin biopsy showed plenty of spindle shaped mast cells with eosinophilic cytoplasm infiltrating the dermis and the appendiceal structures. The diagnosis of cutaneous mastocytosis (urticaria pigmentosa) was made. The child received symptomatic relief with chronic oral hydroxyzine and ranitidine therapy. Automated epinephrine self-injectors usually prescribed in this condition for self-management of anaphylactic episodes were not available. Intramuscular administration of (1:1000) diluted adrenaline via a disposable tuberculin syringe was taught to the mother. A medical bracelet containing her diagnosis and instructions in emergency was custom-made for her.

Guidelines for Safe Surgery in Patients with Systemic Mastocytosis

Systemic mastocytosis (SM) is a rare disorder with important perioperative implications. The physiological stress of operative procedures and a variety of anesthetic and analgesic medications can be triggers of acute exacerbation of this condition. We present two patients with systemic mastocytosis. One underwent open left inguinal hernia and umbilical hernia repair and the other laparoscopic ventral hernia repair. The literature for perioperative management of patients with SM is extensively reviewed. Both patients were treated preoperatively with intravenous antihistamines and steroids to minimize SM reactions. The first patient underwent uneventful open left inguinal hernia repair and umbilical hernia repair under spinal anesthesia. The second patient underwent general anesthesia. A composite mesh was used to repair a 9 x 12-cm Swiss cheese incisional hernia at the site of previous surgery. After the administration of neostigmine and glycopyrrolate, she developed a generalized rash without any hemodynamic instability. The patient was treated with intravenous Solu-Medrol and Benadryl and was extubated successfully and had an unremarkable postoperative course. Patients with SM require careful perioperative management for surgery under spinal and general anesthesia. These patients can undergo surgical procedures safely and effectively without compromising the standard of care.

Non-solid oncogenes in solid tumors: EML4-ALK fusion genes in lung cancer

It is generally accepted that recurrent chromosome translocations play a major role in the molecular pathogenesis of hematological malignancies but not of solid tumors. However, chromosome translocations involving the e26 transformation-specific sequence transcription factor loci have been demonstrated recently in many prostate cancer cases. Furthermore, through a functional screening with retroviral cDNA expression libraries, we have discovered the fusion-type protein tyrosine kinase echinoderm microtubule-associated protein like-4 (EML4)-anaplastic lymphoma kinase (ALK) in non-small cell lung cancer (NSCLC) specimens. A recurrent chromosome translocation, inv(2)(p21p23), in NSCLC generates fused mRNA encoding the amino-terminal half of EML4 ligated to the intracellular region of the receptor-type protein tyrosine kinase ALK. EML4-ALK oligomerizes constitutively in cells through the coiled coil domain within the EML4 region, and becomes activated to exert a marked oncogenicity both in vitro and in vivo. Break and fusion points within the EML4 locus may diverge in NSCLC cells to generate various isoforms of EML4-ALK, which may constitute approximately 5% of NSCLC cases, at least in the Asian ethnic group. In the present review I summarize how detection of EML4-ALK cDNA may become a sensitive diagnostic means for NSCLC cases that are positive for the fusion gene, and discuss whether suppression of ALK enzymatic activity could be an effective treatment strategy against this intractable disorder.

Cutaneous mastocytosis: a review focusing on the pediatric population

Cutaneous mastocytosis can be divided into 4 different clinical variants--urticaria pigmentosa, solitary mastocytoma, diffuse cutaneous mastocytosis, and telangiectasia macularis eruptiva perstans. Skin findings are often accompanied by symptoms secondary to mast cell release of mediators. These symptoms can be both localized to the skin lesion and systemic because of the release of mediators into the bloodstream. The majority of pediatric cases of cutaneous mastocytosis show a good prognosis with gradual resolution of both symptoms and skin lesions. This article will review each of the 4 clinical presentations focusing on pediatric-onset of disease while reviewing the literature.

Pediatric mastocytosis: routine anesthetic management for a complex disease

BACKGROUND

Pediatric mastocytosis consists of a spectrum of clinical variants characterized by increased numbers of resident mast cells in various organ systems. Mast cells are instrumental in mediating anaphylaxis and patients with mastocytosis are at risk to develop provoked and unprovoked episodes of anaphylaxis.

METHODS

We examined perianesthetic records of patients with pediatric mastocytosis who were anesthetized for diagnostic and surgical procedures from 1993 to 2006. In addition, we conducted a literature review of the anesthetic experience in pediatric mastocytosis.

RESULTS

Twenty-two patients with pediatric mastocytosis, with a median age of 3.2 yr (range, 6 mo-20 yr) at the time of the procedure, were anesthetized for 29 diagnostic and surgical procedures. All variants of the disease are represented in this series. Most patients had a history of flushing, pruritus, gastro-esophageal reflux diseases, and abdominal pain; one patient had a history of spontaneous anaphylaxis. Routine anesthetic techniques were used and, despite the complexity of the disease, the perioperative courses were uncomplicated and without serious adverse events.

CONCLUSIONS

We reviewed the main features of pediatric mastocytosis, its anesthetic and perioperative implications, and describe a practical approach to the anesthetic management of pediatric patients with the disease. Although many drugs used routinely in anesthesia reportedly caused mast cell degranulation, deviations from routine anesthesia techniques are not necessarily warranted. However, an understanding of the anesthetic implications of the disease and meticulous preparation to treat possible adverse events are advised.

Recent advances in the understanding of mastocytosis: the role of KIT mutations

Mastocytosis is a heterogeneous disorder characterised by the expansion and accumulation of mast cells in different organs and tissues. Mast cell physiology is closely dependent on activation of the stem cell factor/Kit signalling pathways and accumulating evidences confirm the physiopathological key role of activating KIT mutations (typically D816V) in mastocytosis and their relationship with the clinical manifestations of the disease. This paper reviews the most recent advances in the understanding of the molecular mechanisms associated with KIT mutations in mastocytosis, including recent data about the use of new therapies targeting the Kit molecule and its associated downstream signalling pathways.

Anetodermic mastocytosis: response to PUVA therapy

Mastocytosis is a group of disorders characterized by the accumulation of mast cells in different tissues and organs. The skin is the most frequently involved organ (90% of cases) where mastocytosis may show a heterogenic clinical expression. Anetodermic lesions are an unusual clinical presentation of mastocytosis. We report a case of anetodermic mastocytosis in a 26-year-old man, with sparse lesions and a benign course. PUVA therapy obtained excellent results in this case. Darier's sign should be investigated in patients with anetodermic lesions of unclear origin in order to exclude cutaneous mastocytosis.

Cutaneous mastocytosis: demographic aspects and clinical features of 55 patients

BACKGROUND

Mastocytosis is a rare, heterogeneous group of disorder with abnormal increase of mast cells in one or more organ systems.

OBJECTIVE

To evaluate the demographic and clinical features of cutaneous mastocytosis (CM).

METHODS

Records of 55 patients with cutaneous mastocytosis were retrospectively analysed.

RESULTS

Of the 22 females and 33 males, 80% had urticaria pigmentosa/maculopapular CM and 20% had mastocytoma. Of all cases, 81.8% had first lesions in childhood. The most common presentation was involvement of trunk together with extremities. Thirteen (23.6%) patients had history of bulla; Darier's sign was positive in 34 of 38 patients. Itching was the most common complaint, provocated by hot weather/bath.

CONCLUSION

Clinical presentations of urticaria pigmentosa/maculopapular CM and mastocytoma are similar regarding gender, age of onset, age of diagnosis, and presence of Darier's sign and history of bulla. In contrast to mastocytoma, urticaria pigmentosa/maculopapular CM lesions were frequently located on trunk together with extremities.

Interstitial cystitis in a woman with systemic mastocytosis

Studies have reported detrusor mastocytosis in patients with interstitial cystitis. The author describes a patient with systemic mastocytosis who was confirmed to have detrusor mastocytosis and interstitial cystitis. She responded to therapy with pentosanpolysulfate. The literature on systemic mastocytosis and the role of mast cells in the pathophysiology of interstitial cystitis are reviewed.

The role of c-KIT in tumorigenesis: evaluation in canine cutaneous mast cell tumors

The c-KIT proto-oncogene has been implicated in the pathogenesis of several neoplastic diseases, including gastrointestinal stromal tumors and mastocytosis in humans, and mast cell tumors (MCTs) in canines. Cutaneous MCTs are common neoplasms in dogs and have a variable biologic behavior. The goal of this study was to define the prognostic significance of c-KIT mutations identified in canine MCTs and the associations between c-KIT mutations, KIT localization, and KIT expression levels. Microdissection and polymerase chain reaction were performed on 60 MCTs to identify c-KIT mutations. Anti-KIT antibodies were used for immunohistochemical evaluation of KIT localization. Forty-two MCTs were included in a tissue microarray, and KIT expression was quantified using immunofluorescence. Canine MCTs with c-KIT mutations were significantly associated with an increased incidence of recurrent disease and death. c-KIT mutations were also significantly associated with aberrant protein localization; however, the level of KIT expression did not correlate with either c-KIT mutations or changes in protein localization. Considering the high prevalence of canine MCTs and the central role of c-KIT in the tumorigenesis of certain tumors, canine MCTs are an excellent model for characterizing the role of c-KIT in neoplastic diseases and is a potential target for novel therapeutic agents in clinical trials.

Treatment of Systemic Mastocytosis

It is an exciting time in the treatment of systemic mastocytosis. Major advances in the past 2 decades have helped to define the molecular abnormalities associated with this disease and to delineate pathways involved in its pathogenesis. This has directly translated into the development of novel targeted therapies. These therapies hold great promise to patients and health care providers that a "cure" for systemic mastocytosis may someday be obtainable.

Anesthetic management of a labouring parturient with urticaria pigmentosa

PURPOSE

To report the anesthetic management of labour pain and Cesarean section in a patient with urticaria pigmentosa at risk for systemic mastocytosis. CLINICAL: A 37-yr-old patient with a history of urticaria pigmentosa and an allergic reaction to a local anesthetic agent was seen in consultation at 36 weeks gestation. She previously tested negative for an allergy test to lidocaine. Recommendations to avoid systemic mastocytosis included: avoidance of histamine-releasing drugs, using lidocaine for labour epidural, and regional anesthesia in case of a Cesarean section. The patient presented at term in labour. Intravenous fentanyl was used for early labour, followed by a combined spinal-epidural. The spinal contained lidocaine and fentanyl, but because of pruritus, the epidural infusion contained lidocaine only. Most likely because of tachyphylaxis to lidocaine, an epidural bolus of lidocaine with epinephrine failed to provide adequate anesthesia for a Cesarean section. The block was supplemented with nitrous oxide by mask, with fentanyl postdelivery. Postoperative pain control was managed with an epidural infusion of lidocaine and fentanyl for three days. The patient was discharged without complications four days postsurgery.

CONCLUSION

Proper allergy testing prior to pregnancy is important to help the management of labour pain and anesthesia for Cesarean section in a patient at risk for systemic mastocytosis.

An unusual presentation of mastocytosis: unilateral swelling of the vulva

Mastocytosis is a primary, abnormal accumulation of mast cells associated with a broad range of local and systemic symptoms. We report two female adolescents with episodic, unilateral, swelling of the labia majora that was discovered to be an unusual presentation of mastocytosis. Mastocytosis is frequently misdiagnosed because of its rarity and variable clinical presentation, which often mimics other conditions. In the appropriate setting, mastocytosis should be included in the differential diagnosis of labium majus swelling.

Antihistamines in Dermatology

Along with antibiotics, antihistamines are the most widely used systemic drugs in dermatology. This is attributable to the major role played by histamine in common diseases such as urticaria and atopic eczema. Of the currently recognised four subtypes of G protein-coupled histamine receptors, only the H1 and H2 subtypes have been positively identified in human skin. Traditionally believed to be competitive antagonists of histamine, H1 and H2 antihistamines are now considered to behave as inverse agonists. By consensus, H1 antihistamines are classified as 'first generation' (associated with troublesome side-effects including somnolence, anti-adrenergic and atropine-like actions) and 'second-generation' compounds (in which these side-effects are reduced or absent). The main indications for H1 antihistamines in skin are suppression of pruritus in urticaria and atopic eczema, both of which are associated with increased mast cell numbers and tissue histamine levels. However the evidence basis for use in atopic eczema is ambiguous and controversial, even though these drugs are widely used in practice. Currently, significant side-effects are mainly confined to the first-generation compounds and are especially troublesome in the elderly. Psychomotor impairment may persist throughout the day following administration. Anti-cholinergic and anti-alpha-adrenergic blockade and cardiotoxicity (torsade de pointes) may also occur with first-generation antihistamines. Two early low-sedation second-generation antihistamines caused arrhythmias in a small number of patients but these compounds have now been withdrawn. Generally, the second-generation H1 antihistamines are well tolerated.