Gastrointestinal stromal tumor with a platelet-derived growth factor receptor-alpha mutation

A 44-year-old man visited a local hospital, complaining of abdominal pain. The patient presented with muscular guarding in the upper abdomen and moderate anemia (hemoglobin, 6.7 g/dL). Computed tomography revealed a 9.0-cm tumor adjacent to the stomach and massive ascites (Panel A). The patient was diagnosed with hemoperitoneum caused by tumor rupture, and underwent laparotomy. Pathological examination revealed that the excised tumor was microscopically composed of cytoplasm-rich polygonal cells that were immunohistochemically positive for CD34 but negative for KIT (Panel B). Gene analyses revealed that the tumor had a deletion mutation in exon 18 (del 842-845) of platelet-derived growth factor receptor alpha (PDGFRA). Based on this finding, confirmative diagnosis of gastrointestinal stromal tumor (GIST) of the stomach was made. Despite tumor rupture, which is a significant risk factor for recurrence, the patient was postoperatively followed up without adjuvant treatment with imatinib because the PDGFRA-mutated GIST was reportedly resistant to the tyrosine kinase inhibitor (1). Eight years after the surgery, the patient is alive with no evidence of disease recurrence.

Clinical points

• KIT-negative, epithelioid-type GISTs of the stomach should be examined for PDGFRA mutations.
• PDGFRA-mutated GISTs are clinically indolent in general.
• Tumor gene analysis should be considered before starting adjuvant imatinib therapy.

Acknowledgments

Funding: None.

Footnote

Provenance and Peer Review: This article was commissioned by the editorial office, Gastrointestinal Stromal Tumor for the series “Images in Clinical Medicine”. The article did not undergo external peer review.

Conflicts of Interest: The authors have completed the ICMJE uniform disclosure form (available at http://dx.doi.org/10.21037/gist.2019.01.01). The series “Images in Clinical Medicine”was commissioned by the editorial office without any funding or sponsorship. TK serves as the unpaid guest editor of the series and serves as an unpaid editorial board member of Gastrointestinal Stromal Tumor from Oct 2018 to Sep 2020. The other authors have no conflicts of interest to declare.

Ethical Statement: The authors are accountable for all aspects of the work in ensuring that questions related to the accuracy or integrity of any part of the work are appropriately investigated and resolved. All procedures performed in studies involving human participants were in accordance with the ethical standards of the institutional and/or national research committee(s) and with the Helsinki Declaration (as revised in 2013). Written informed consent was obtained from the patient for publication of this case report and any accompanying images.

Open Access Statement: This is an Open Access article distributed in accordance with the Creative Commons Attribution-NonCommercial-NoDerivs 4.0 International License (CC BY-NC-ND 4.0), which permits the non-commercial replication and distribution of the article with the strict proviso that no changes or edits are made and the original work is properly cited (including links to both the formal publication through the relevant DOI and the license). See: https://creativecommons.org/licenses/by-nc-nd/4.0/.

References

1. Heinrich MC, Corless CL, Demetri GD, et al. Kinase mutations and imatinib response in patients with metastatic gastrointestinal stromal tumor. J Clin Oncol 2003;21:4342-9. [Crossref] [PubMed]