Myxoid epithelioid gastrointestinal stromal tumor harboring an unreported PDGFRA mutation: report of a case and review of the literature.

Abstract

Activating mutations of platelet-derived growth factor receptor α (PDGFRA) are detected in a significant proportion of gastrointestinal stromal tumors (GISTs), in addition to the more frequent mutation in c-kit. GISTs with PDGFRA mutations have been found to have several characteristic morphological features, sometimes allowing to discriminate them from GISTs with c-kit mutations. Among these, epithelioid morphology in tumor cells and tumor-infiltrating mast cells are powerful predictors of PDGFRA mutations. Although myxoid stroma by itself is not so much a reliable predictor of PDGFRA mutation, myxoid stroma in conjunction with epithelioid morphology in tumor cells is a powerful predictor of mutations in this gene. GISTs showing either weak or negative immunoreactivity for c-kit and epithelioid cells with myxoid stroma are called myxoid epithelioid GISTs, which typically show PDGFRA mutation. Herein, we presented a case of a 59-year-old woman with myxoid epithelioid GIST of the stomach. A unique finding in this case was eosinophil infiltration, probably more numerous than mast cells; mast cell infiltration is known to be usually found in myxoid epithelioid GIST. The existence of a similar mechanism in eosinophil and mast cell recruitment via tumor-producing stem cell factor is speculated. Mutational analyses revealed a PDGFRA exon 18 mutation: D842_H845del, D846N. Combined deletion and substitution mutation has been reported in rare instances, but to the best of our knowledge, D846N has not been documented.

• Authors: Shogo Tajima, Akihiko Ohata, Kenji Koda, Yasuhiko Maruyama
• Journal: International journal of clinical and experimental pathology (Int J Clin Exp Pathol) Vol. 8 Issue 5 Pg. 5821-9 ( 2015) ISSN: 1936-2625 [Electronic] United States
• PMID: 26191304 (Publication Type: Case Reports, Journal Article, Review)

Chemical References

• Biomarkers, Tumor
• Receptor, Platelet-Derived Growth Factor alpha

Topics

• Base Sequence
• Biomarkers, Tumor (analysis, genetics)
• Biopsy
• DNA Mutational Analysis
• Epithelioid Cells (chemistry, pathology)
• Exons
• Female
• Gastrectomy
• Gastrointestinal Stromal Tumors (chemistry, genetics, pathology, surgery)
• Gastroscopy
• Genetic Predisposition to Disease
• Humans
• Immunohistochemistry
• Middle Aged
• Molecular Sequence Data
• Phenotype
• Receptor, Platelet-Derived Growth Factor alpha (genetics)
• Sequence Deletion
• Stomach Neoplasms (chemistry, genetics, pathology, surgery)
• Tomography, X-Ray Computed