Cytogenetic and molecular aberrations and worse outcome for male patients in systemic mastocytosis.

In systemic mastocytosis (SM), the clinical features and survival vary greatly. Patient-related factors determining the outcome in SM are largely unknown. Methods: We examined the impact of sex on the clinical features, progression-free survival (PFS), and overall survival (OS) in 3403 patients with mastocytosis collected in the registry of the European Competence Network on Mastocytosis (ECNM). The impact of cytogenetic and molecular genetic aberrations on sex differences was analyzed in a subset of patients. Results: Of all patients enrolled, 55.3% were females. However, a male predominance was found in a subset of advanced SM (AdvSM) patients, namely SM with an associated hematologic neoplasm (SM-AHN, 70%; p < 0.001). Correspondingly, organomegaly (male: 23% vs. female: 13%, p = 0.007) was more, whereas skin involvement (male: 71% vs. female: 86%, p = 0.001) was less frequent in males. In all patients together, OS (p < 0.0001) was significantly inferior in males, and also within the WHO sub-categories indolent SM, aggressive SM (ASM) and SM-AHN. PFS was significantly (p = 0.0002) worse in males when all patients were grouped together; due to low numbers of events, this significance persisted only in the subcategory smoldering SM. Finally, prognostically relevant cytogenetic abnormalities (10% vs. 5%, p = 0.006) or molecular aberrations (SRSF2/ASXL1/RUNX1 profile; 63% vs. 40%, p = 0.003) were more frequently present in males. Conclusions: Male sex has a major impact on clinical features, disease progression, and survival in mastocytosis. Male patients have an inferior survival, which seems related to the fact that they more frequently develop a multi-mutated AdvSM associated with a high-risk molecular background.

Aleukemic leukemia presenting with paranoid psychosis.

Mast cells not only synthesize and release serotonin, but also express and are activated through multiple serotonin receptors. Low blood serotonin level might define a specific subset of patients with systemic mastocytosis (SM) who are more likely to present with neurologic and gastrointestinal complaints. Mast cell leukemia (MCL) is a rare and aggressive type of systemic mastocytosis, and psychiatric manifestations in its course have not been well-characterized. We describe herein a unique patient with a KIT D816V mutation positive a leukemic leukemia variant of systemic mastocytosis with gastrointestinal involvement, presenting with a severe and sustained paranoid delusional illness. While diarrhea improved with the use of histamine H1 and H2 receptor antagonists, the psychosis did not, and the disease followed a dramatic course with a rapidly fatal outcome. As there is paucity of literature, diagnosis of MCL presenting with psychiatric symptoms remains a diagnostic challenge and warrants clinicians to be alert of this rare possibility.

Mast cell leukemia with rapidly progressing portal hypertension.

Reported herein is an autopsy case of mast cell leukemia, a rare form of systemic mastocytosis, complicated with portal hypertension. A 52-year-old woman presented with urticaria-like skin symptoms, anemia, and thrombocytopenia. Atypical mast cells (CD2+, CD25+, CD117+) with toluidine blue metachromasia were found in the peripheral blood and on bone marrow aspiration smears. Chemotherapy with cytosine arabinoside and idarubicin was ineffective and the patient died of multi-organ failure with rapidly progressing hepatosplenomegaly and large-volume ascites 3 months after admission. At autopsy the bone marrow, spleen, liver, and lymph nodes were extensively infiltrated by atypical tumor cells with occasional bi- or multi-lobated nuclei. They were positive for mast cell tryptase and possessed an activating mutation of the c-kitgene (D816V). Ascites (2200 mL) and non-ruptured esophageal varices with submucosal hemorrhage indicated the presence of severe portal hypertension. Although there was no evidence of liver cirrhosis, the hepatic sinusoids were clogged with tumor cells, with a tendency to be more severe in the perivenular areas, and the lumens of central veins were obliterated by tumor cell infiltration. The present case demonstrates that non-cirrhotic portal hypertension due to blocking of sinusoidal and venous flow could be a serious complication in mast cell leukemia.

Purification of tryptase from a human mast cell line.

The neutral protease tryptase has been isolated from a human mast cell line, HMC-1. The HMC-1 line was established from the peripheral blood of a patient with mast cell leukemia and maintained as continuously proliferating clones in vitro and as solid mast cell tumors in nude mice. HMC-1-derived tryptase was purified by sequential chromatography on Dowex 1, DEAE 5 PW, and heparin-agarose. Purified tryptase has an apparent molecular weight of 150,000, as determined by molecular sieve HPLC, but migrates as a doublet of bands of 32/35,000 on SDS-PAGE gels. Maximal enzymatic activity was observed at pH 8.5. Cleavage of tosyl-L-arginine methyl ester by purified tryptase was inhibited by dansyl-L-glutamyl-glycyl-L-arginine chloromethyl ketone 2 HCl, HgCl2, tosyl-L-lysine chloromethyl ketone, leupeptin, and PMSF but not by benzamidine, aprotinin, tosyl-L-phenyl-alanine chloromethyl ketone, soybean trypsin inhibitor, human plasma, ovomucoid inhibitor, or lima bean trypsin inhibitor. Microsequencing of purified tryptase yielded an amino terminal sequence that was identical to that previously reported for human pituitary-derived tryptase.