Multiple non-metastatic gastrointestinal stromal tumors: Differential features

Introduction: gastrointestinal stromal tumors (GISTs) are spe cific, generally KIT (CD117)-positive, mesenchymal tumors of the digestive tract displaying KIT or PDGFRA gene mutations. Clini cally, they tend to present as solitary tumors of the intestinal wall; more rarely, multiple tumors may occur in one or more organs. Objective: to review the morphological, immunohistochemi cal and molecular features of multiple, non-metastatic forms of GIST. Sources: review of the literature on Medline, and authors’ own experience. Conclusions: multiples GISTs may occur in three different contexts: as spontaneous lesions (in both adults and children); due to familial GIST syndrome (autosomal dominant inheritance); or in association with specific syndromes (e.g. Carney’s triad, Car ney-Stratakis syndrome, type I neurofibromatosis). Outside these contexts, the existence of multiple GISTs is deemed to be the re sult of tumor metastasis, and therefore indicative of advancedstage disease. Clinicians need to be aware of these variants, whose prognosis and treatment differ.