Effects of tixocortol pivalate on gastrointestinal disease in systemic mastocytosis: a preliminary study

Mastocytosis: update on pharmacotherapy and future directions

INTRODUCTION

Mastocytosis is a disorder characterized by abnormal mast cell (MC) accumulation in skin and internal organs such as bone marrow. The disease follows a benign course in most patients with cutaneous and indolent systemic mastocytosis (SM); however, advanced variants associated with decreased life expectancy also exist. Pharmacotherapy of mastocytosis is aimed at the control of symptoms caused by MC mediator release, treatment of comorbidities and cytoreductive therapies in advanced variants.

AREAS COVERED

This article will cover the general treatment principles of anti-MC mediator and cytoreductive therapies of mastocytosis. The literature discussed was retrieved with PubMed using the search terms 'treatment of mastocytosis,' 'mastocytosis antimediator therapy' and looking for important cross-references.

EXPERT OPINION

Pharmacotherapy of mastocytosis should be individualized for each patient considering the category of disease, reduction of risk of anaphylaxis, constitutional symptoms and comorbidities including osteoporosis. Cytoreductive therapies are generally reserved for patients with aggressive mastocytosis (ASM), MC leukemia (MCL) and MC sarcoma (MCS); however, some patients with indolent disease and recurrent anaphylactic episodes not responsive to antimediator therapies may also be considered for cytoreduction on a case-by-case basis.

Gastrointestinal involvement and manifestations in systemic mastocytosis

Mastocytosis is a rare and heterogeneous disease characterized by various biological and clinical features with different prognosis and treatments. The disease is usually divided into 2 categories: a pure cutaneous and a systemic disease. Clinical features can be related to mast cells' mediators release or to pathological mast cells infiltration. The diagnosis of mastocytosis is based on clinical, biological, histological, and molecular international criteria. Among all manifestations of the disease, gastrointestinal (GI) symptoms are common and can significantly impair the quality of life. The aim of this article is to review the data regarding GI involvement in mastocytosis. Articles dealing with clinical, pathophysiological, and therapeutic aspects of mastocytosis GI tract involvement were searched for using PubMed. GI manifestations in mastocytosis are reviewed. Pathogenesis of GI symptoms in systemic mastocytosis and their treatment are critically discussed. The most frequent GI symptoms are abdominal pain, diarrhea, nausea, and vomiting. GI lesions may involve all the digestive tract, from the esophagus to the rectum. The histological diagnosis of GI involvement is difficult. The treatment of GI symptoms aims to prevent and limit mast cells degranulation and/or its consequences and more rarely to control tumoral mast cells infiltration. The high prevalence of GI symptoms in mastocytosis and their important functional impact deserves better characterization and treatment in order to improve patients' quality of life. Diagnosis of mastocytosis GI manifestations should be evoked in the case of unexplained severe GI disorders.

Systemic mastocytosis involving the gastrointestinal tract: clinicopathologic and molecular study of five cases

Systemic mastocytosis is an uncommon condition characterized by abnormal proliferation of mast cells in one or more organ. The specific D816V KIT mutation is present in most cases. Gastrointestinal symptoms occur commonly but histologic characterization of gastrointestinal involvement is incomplete. The purpose of this study was (1) to describe the clinicopathologic features in five patients with systemic mastocytosis involving the gastrointestinal tract and (2) to determine whether gastrointestinal involvement is associated with the usual D816V mutation or a different mutation. Clinical details were obtained from the hospital of origin or referring pathologist. Histologic features were documented in slides stained with hematoxylin and eosin, mast cell tryptase and CD117. Molecular analysis for the D816V KIT mutation was performed on formalin-fixed paraffin-embedded sections. Symptoms included diarrhea/loose stools (n=5), abdominal pain (n=4), vomiting (n=3) and weight loss (n=3). Other findings included cutaneous lesions of mastocytosis (n=4), malabsorption (n=2), hypoalbuminemia (n=2) and constitutional growth delay (n=1). Sites of gastrointestinal involvement included the colon (n=5), duodenum (n=3) and terminal ileum (n=3). Endoscopic/gross findings included mucosal nodularity (n=4), erosions (n=2) and loss of mucosal folds (n=2). In three patients the endoscopic appearance was considered consistent with inflammatory bowel disease. All cases showed increased mast cell infiltration of the lamina propria, confirmed by immunohistochemistry for mast cell tryptase and CD117. In two cases, mast cells had abundant clear cytoplasmic resembling histiocytes. Marked eosinophil infiltrates were present in four patients, in one patient leading to confusion with eosinophilic colitis. Architectural distortion was noted in three cases. The D816V KIT mutation was present in all four cases tested. In conclusion, gastrointestinal involvement by systemic mastocytosis is characterized by a spectrum of morphologic features that can be mistaken for inflammatory bowel disease, eosinophilic colitis or histiocytic infiltrates. Systemic mastocytosis involving the gastrointestinal tract is associated with the usual D816V KIT mutation.

Immunoreactivity for CD25 in gastrointestinal mucosal mast cells is specific for systemic mastocytosis

Systemic mastocytosis (SM) is characterized by the accumulation of neoplastic mast cells in bone marrow and other organs. Gastrointestinal (GI) symptoms are common in both SM and cutaneous mastocytosis [urticaria pigmentosa (UP)], and are usually caused by the release of histamine and other inflammatory mediators. Occasionally, neoplastic mast cells may also directly infiltrate the GI tract. Previous studies have suggested that enumeration of the mast cells in GI biopsies may help establish the diagnosis of SM. However, mast cells have been reported to be increased in various inflammatory diseases, and mast cell density has not been systematically evaluated in other GI disorders. Recently, expression of CD25 by mast cells in bone marrow has been shown to be specific for SM. The purpose of this study was (1) to quantitate and compare mast cells in mucosal biopsies from patients with SM involving the GI tract, UP with GI symptoms, and a control group of diverse inflammatory disorders, and (2) to determine whether immunostaining for CD25 can be used to distinguish neoplastic from reactive mast cells in GI biopsies. Seventeen GI biopsies from 6 patients with SM; 17 GI biopsies from 5 patients with UP; and 157 control cases including 10 each normal stomach, duodenum, terminal ileum, and colon, Helicobacter pylori gastritis, bile reflux gastropathy, peptic duodenitis, celiac disease, Crohn disease, ulcerative colitis, lymphocytic colitis, and collagenous colitis, 20 biopsies from 16 patients with irritable bowel syndrome, 8 biopsies from 5 patients with parasitic infections, and 9 biopsies from 7 patients with eosinophilic gastroenteritis were immunostained for mast cell tryptase, c-kit (CD117), and CD25. Mucosal mast cells were quantitated, and the presence or absence of CD25 expression on mast cells was determined. In SM patients, mast cells in the small intestine and colon numbered >100/high-power field (HPF) in nearly all cases (mean 196/HPF; range 74 to 339). This was significantly higher than in GI biopsies from UP patients (mean 17/HPF; range 8 to 32, P<0.0001) and all inflammatory diseases (P<0.01). Mast cell density in other disorders ranged from a mean of 12/HPF in H. pylori gastritis to 47/HPF in parasitic infections. Interestingly, all SM biopsies (and none of the other cases) contained aggregates or confluent sheets of mast cells. In addition, mast cells in all SM cases were positive for CD25, whereas GI mucosal mast cells in UP and all other control cases were negative. In conclusion, quantitation of mast cells can be helpful to diagnose SM in GI mucosal biopsies, although mast cells are also markedly increased in parasitic infections. Aggregates or sheets of mast cells are only seen in SM. Immunoreactivity for CD25 in GI mucosal mast cells is specific for SM and can be used to confirm the diagnosis.

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.

[Treatment of systemic mastocytosis]

BACKGROUND

Systemic mastocytosis is a rare disease, characterized by mast cells proliferation in various organs. Two types of clinical manifestations can be distinguished: those related to mast cells mediators release and those related to tumoral proliferation involving different organs, these later defining aggressive systemic mastocytosis. Until recently, treatment was mainly symptomatic, without anti tumoral effect.

RECENT FACTS

These last years, advances have been made in the understanding of the disease with the discovery of the c-kit oncogene mutation and the approach of the disease as a myeloproliferative disorder.

PERSPECTIVES

Based on experiences acquired in the treatment of this kind of disorders, evaluation of new therapeutics, such as cladribine or combination of interferon-alpha and cytarabine is in progress. At least, tyrosine kinase inhibitors, a new family of molecules, are able of inhibiting some types of the mutated c-kit protein and one of them, imatinib mesylate, has shown a great efficacy in the treatment of gastro intestinal stromal tumors (GIST) which also involves the c-kit mutation. By analogy, treatment of patients with c-kit susceptible mutation might be treated with this molecule.

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.

Gastrointestinal abnormalities and involvement in systemic mastocytosis

Recent studies have shown that involvement of the gastrointestinal tract is much more frequent than originally reported in patients with systemic mastocytosis. Seventy percent to 80% of patients with systemic mastocytosis are found to have gastrointestinal symptoms when a careful history is taken, and abnormalities in the gastrointestinal tract are frequently detected by endoscopic studies, functional studies of absorption, and barium studies. Because of the rarity of the disease, there are few prospective studies of gastrointestinal involvement, so the actual frequency of upper and lower gastrointestinal lesions is unknown. Furthermore, there have been no studies correlating endoscopic abnormalities of the lower gastrointestinal tract with the presence or absence of diarrhea, which is a frequent symptom (mean, 43% [range 14%-100%]). A review of gastric acid studies reveals that a proportion of patients develop gastric acid hypersecretion because of the hyperhistaminemia, which can result in ulcer disease that in turn can cause dyspeptic pain, small intestinal mucosal damage, and malabsorption. In some patients gastric acid hypersecretion in the range seen in Zollinger-Ellison syndrome can develop. A number of studies suggest that the prevalence of peptic ulcer disease has been underestimated in these patients and is certainly higher than the general population. The exact physiologic basis for the diarrhea or nondyspeptic abdominal pain remains largely unknown in these patients. Whereas some studies suggest small intestinal mucosal abnormalities are responsible for most cases of malabsorption not associated with gastric acid hypersecretion, this supposition also remains unproven. Hepatomegaly, portal hypertension, splenomegaly, and ascites occur frequently in patients with systemic mastocytosis, especially those with category II through IV disease. Whereas the histology of the liver and spleen and alterations in hepatic function studies have been well studied, the pathogenesis of each of these abnormalities has not been well studied, and almost all the information comes from a few well-studied case reports.

Southwestern Internal Medicine Conference: mastocytosis: developments during the past decade

Mastocytosis is a spectrum of disorders characterized by an aberrant proliferation of tissue mast cells. Although this disease process often affects the skin, it may involve multiple organs. The clinical disorder varies according to patient age, the clinical manifestations demonstrated, and the extent of the mast cell proliferative process. A myriad of clinical symptoms occur, and these may be localized to the organ system involved or may be systemic, depending on whether there is local or generalized mast cell mediator release. Diagnosis includes the demonstration of increased tissue mast cells in involved organs as well as increased levels of biochemical mediators. Patients with cutaneous involvement only have the best prognosis. Treatment is directed toward stabilizing mast cell mediator release and blocking the effects of those mediators generated.