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Near-Fatal Mastocytosis Mimicking as Malignant Vasovagal Syncope

Year: 2025

Type: article

Abstract: BACKGROUND: Severe apparent reflex syncope may have other causes. CASE SUMMARY: A young girl was investigated for recurrent faints expected to be caused by reflex syncope, but ultimately complicated by cerebral ischemic lesions. A diagnosis of systemic mastocytosis (bone marrow mastocytosis) was finally made, after documentation of short-living abnormal coagulation tests and transient elevated tryptase levels. DISCUSSION: Severe mastocytosis-related vasoplegia can be the underlying cause of syncope and prolonged cerebral ischemia. Mastocytosis is a clonal disorder stemming from an acquired somatic mutation leading to the accumulation of atypical mast cells carrying the risk of massive and brutal release of mediators such as histamine, tryptase, and coagulation factors. TAKE-HOME MESSAGE: Systemic mastocytosis should be systematically considered in case of any unexplained hypovolemic shock or recurrent syncope with vasovagal features.

Source: JACC Case Reports

DOI: 10.1016/j.jaccas.2025.106290