Gastrointestinal tumors in transplantation: Two case reports and review of literature

Abstract

Background: Gastrointestinal stromal tumors (GISTs) are the most common mesenchymal tumors of the gastrointestinal tract. As most of them harbor a KIT mutation (75%), selective kinase inhibitors are the therapeutic option and show a sustained objective response among patients with metastatic or unresectable GISTs. A well-known higher risk of neoplasm has been described among renal transplant recipients (RTRs). Nevertheless, only few cases of GIST onset among transplant patients have been reported in the literature.

Case summary: Here, we describe 2 cases of gastric GIST occurring during the follow-up of RTRs. We also review the existing literature concerning GIST occurrence in transplant patients. In total and in association with our 2 cases, 16 patients have been reported. The median age was 59.5 years and 69% were male. With a median tumor size of 45 mm, no patient displayed metastatic dissemination at diagnosis. Time from transplantation to diagnosis was highly variable between 5 mo and 21 years. Histopathological data mostly revealed high risk of progression (43%). Death increased to 29% during follow-up. Surgical treatment was systematically performed when the tumor was operable (94%). The use of adjuvant therapy was uncommon (19%).

Conclusion: GISTs represent rare but potentially severe malignant complication among transplant patients.

Keywords: Case report; Gastrointestinal stromal tumors; Imatinib mesylate; Kidney transplantation; Proto-oncogene protein c-KIT; Transplantation.

Figure 1

Histopathological features of case 1 gastrointestinal stromal tumor. A: Hematoxylin and eosin staining showing exophytic development of a tumor from the mucosa musculus (magnification, 2.5 ×); B: Hematoxylin and eosin staining showing spindle cell morphology composed of relatively uniform cells arranged in short fascicles (magnification, 20 ×); C: Immunohistochemistry showing strong positive staining for the protooncogene c-KIT (white asterisk; magnification, 5 ×); D: Immunohistochemistry showing strong positive staining for discovered on gastrointestinal stromal tumor protein 1 (white asterisk; magnification, 5 ×). M: Mucosa; MM: Mucosa musculus; T: Tumor.