title: Multiple sporadic gastrointestinal stromal tumours arising at different gastrointestinal sites: pattern of involvement of the muscularis propria as a clue to independent primary GISTs.
abstract: Multifocal sporadic gastrointestinal stromal tumours (GISTs) may be misinterpreted as recurrent or metastatic disease, leading to inappropriate treatment. As molecular analysis is generally not available in routine practise, histological criteria that would facilitate diagnosis of multiple primary GISTs in routine slides are needed. We studied 14 GISTs (mean size, 2.7 cm) from six men and one woman (mean age, 70 years) applying morphological features and direct sequencing of KIT, PDGFRA, BRAF, and KRAS. Diagnosis was synchronous in five and metachronous in two patients. Paired tumours originated in stomach/small bowel (n = 5), duodenum/jejunum (n = 1), and stomach/oesophagus (n = 1) and revealed spindle (n = 10) and mixed spindle and epithelioid (n = 4) phenotype. Tumours were well circumscribed and have involved the muscularis propria in a pattern typical of primary GISTs. Different somatic KIT mutations were found in tumours from four patients. One patient had a KIT-mutated and a BRAF-mutated (V600E) tumour. Two patients had wild-type tumours. No PDGFRA or KRAS mutations were detected. Our results underscore the molecular heterogeneity of sporadic multifocal GISTs. The characteristic involvement of the muscularis propria and the site-typical morphology and immunophenotype facilitated the diagnosis of primary GISTs in all cases and correlated with molecular findings, emphasising the value of conventional histology in recognising independent primary GISTs.
authors: Institute of Pathology, University Hospital, 91054 Erlangen, Germany. abbas.agaimy@uk-erlangen.de
authors: Abbas
authors: A
authors: Agaimy
authors: Bruno
authors: B
authors: Märkl
authors: Hans
authors: H
authors: Arnholdt
authors: Peter H
authors: PH
authors: Wünsch
authors: Luigi M
authors: LM
authors: Terracciano
authors: Stephan
authors: S
authors: Dirnhofer
authors: Arndt
authors: A
authors: Hartmann
authors: Luigi
authors: L
authors: Tornillo
authors: Michel P
authors: MP
authors: Bihl
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D004386:Duodenum / Q000378:metabolism / Q000473:pathology; D004947:Esophagus / Q000378:metabolism / Q000473:pathology; D005260:Female; D005753:Gastric Mucosa / Q000378:metabolism; D005770:Gastrointestinal Neoplasms / Q000235:genetics / Q000378:metabolism / Q000473:pathology*; D046152:Gastrointestinal Stromal Tumors / Q000235:genetics / Q000378:metabolism / Q000473:pathology*; D041981:Gastrointestinal Tract / Q000378:metabolism / Q000473:pathology*; D006801:Humans; D015994:Incidence; D007583:Jejunum / Q000378:metabolism / Q000473:pathology; D008297:Male; D008875:Middle Aged; D009092:Mucous Membrane / Q000378:metabolism / Q000473:pathology*; D009154:Mutation / Q000235:genetics; D011518:Proto-Oncogene Proteins / Q000235:genetics / Q000378:metabolism; D048493:Proto-Oncogene Proteins B-raf / Q000235:genetics / Q000378:metabolism; D019009:Proto-Oncogene Proteins c-kit / Q000235:genetics / Q000378:metabolism; D016283:Proto-Oncogene Proteins p21(ras); D020796:Receptor, Platelet-Derived Growth Factor alpha / Q000235:genetics / Q000378:metabolism; D012189:Retrospective Studies; D013270:Stomach / Q000473:pathology; D018631:ras Proteins / Q000235:genetics / Q000378:metabolism
chemical_list: C117307:KRAS protein, human; D011518:Proto-Oncogene Proteins; D019009:Proto-Oncogene Proteins c-kit; D020796:Receptor, Platelet-Derived Growth Factor alpha; C482119:BRAF protein, human; D048493:Proto-Oncogene Proteins B-raf; D016283:Proto-Oncogene Proteins p21(ras); D018631:ras Proteins