Laparoscopic and Endoscopic Cooperative Surgery for Plexiform Angiomyxoid Myofibroblastic Tumor

Abstract

Plexiform angiomyxoid myofibroblastic tumor (PAMT) is a recently described distinctive gastric mesenchymal entity with a peculiar plexiform pattern, bland spindle cells and a myxoid stroma rich in arborizing blood vessels. In this study, we report a new case of this rare gastric tumor resected by laparoscopic and endoscopic cooperative surgery (LECS). A 39-year-old Japanese man was admitted with a gastric mass. Gastroscopy showed an elevated mass in the anterior wall of the gastric antrum. Endoscopic ultrasound examination revealed a focal hypoechoic lesion protruding into the lumen. A partial gastrectomy by LECS was performed, and the patient made an uneventful recovery and remains well 9 months later. The tumor in this case depicted all the typical histopathologic and immunochemical features of gastric PAMT (c-kit negative and smooth muscle actin-positive). Especially, it was characterized by multiple nodules protruding outward within the serosa. Therefore, it is important that the resection line is determined on the serosa to ensure the complete resection of these nodules together.

Keywords: Gastric submucosal tumors; Laparoscopic and endoscopic cooperative surgery; Plexiform angiomyxoid myofibroblastic tumor.

Fig. 1

An upper gastrointestinal endoscopy and ultrasound examination. a There are SMTs on the antrum with focal ulceration of the mucosa. b Focal hypoechoic lesion protruding into the lumen.

Fig. 2

CT scan of the tumor. a Unenhanced CT image shows a inhomogeneous tumor mass in the antrum of the stomach. b, c Contrast-enhanced CT image revealed a tumor mass with an inhomogeneous, prominent enhancement in the late phase of contrast imaging. d Arrow indicates the enhanced small nodules in the serosa.

Fig. 3

Surgical findings. a Port site. b Small polypoid nodules on serosa was connected to the main tumor.

Fig. 4

Gross and histological examination. a 2.3 × 2.8 × 3.5-cm lobulated tumor showed a mixture of white-fibrous, myxomatous small polypoid nodules on serosa which were connected to the main tumor. b The tumor contains spindle-shaped bland tumor cells in a fibromyxoid stroma. HE. ×12.5.

Fig. 5

Immunohistochemistry (×200). The results of other markers were c-kit(–), CD34(–), S-100 protein(–), desmin(–) and EMA(–) but diffusely positive for smooth muscle actin consistent.