Gastric plexiform fibromyxoma resected by endoscopic submucosal dissection after observation of chronological changes: A case report

Abstract

A 66-year-old man was diagnosed with a gastric submucosal tumor. Endoscopic ultrasound (EUS) revealed an iso/hypoechoic mass in the third layer. No malignant cells were detected in a histological examination. Yearly follow-up endoscopy and EUS showed the slow growth of the tumor. Endoscopic submucosal dissection (ESD) was performed and a glistening tumor was resected. The lesion showed a multinodular plexiform growth pattern consisting of spindle cells with an abundant fibromyxoid stroma that was rich in small vessels. The tumor was diagnosed as plexiform fibromyxoma (PF) by immunohistochemistry. Although difficulties are associated with reaching a diagnosis preoperatively, chronological changes on EUS may contribute to the diagnosis of PF. ESD may also be useful in the diagnosis and treatment of PF.

An Update on Clinicopathological and Molecular Features of Plexiform Fibromyxoma

“…Some lymph nodes display enlargement with reactive changes [19, 67]. Vascular or lymphatic involvement was observed in 5 cases [11, 60].…”

“…Since PF is currently considered a benign disease (though not yet verified by convincing evidence), conservative management may be suitable for PF patients, and particularly for the elderly or selected patients with surgically contraindicated comorbidities [72]; at least, more conservative surgical management than partial gastrectomy could be feasible [23]. However, vascular and lymphatic invasion were reported by Miettinen et al and Kawara et al [11, 60], and PF usually develops in a nodular and plexiform pattern with unclear tumor margins [1, 30, 64], suggesting that the possibility of malignancy or local recurrence cannot be fully excluded [9, 73]. Therefore, regardless of the operative technique, we suggest that complete resection still be the first consideration when treating PF rather than consideration of the conservativeness of the operative technique [30, 64, 71].…”

“…Three cases were reported to have died for unknown causes at 2 months, 14.5 years, and 25.5 years after diagnosis [11]. Vascular or lymphatic invasion was noted in 5 cases, none of which had adverse significance on prognosis [11, 60].…”

Loss of the PTCH1 tumor suppressor defines a new subset of plexiform fibromyxoma

“…While slow growth and lack of metastases suggest an indolent natural history, these so-called “benign” tumors often present with upper gastrointestinal bleeding and gastric outlet obstruction. Although the cell of origin remains unknown, PF generally occurs in the gastric muscularis propria and frequently invades into the mucosa and submucosa [1–4]. Histologically, PF is characterized by a multinodular plexiform growth pattern, diffuse myxoid stroma and prominent thin arborizing capillaries.…”

Uninodular Fibromyxomatous Gastric Tumor Resected by Endoscopic Submucosal Dissection

“…Because plexiform fibromyxomas often extend into the muscular layer, endoscopic treatment is not indicated, making laparotomy or laparoscopic surgery the preferred options (3, 6, 7). Two endoscopic treatments for plexiform fibromyxoma have been attempted (12) as far as we can ascertain. However, preoperative EUS revealed a thickened muscle layer in one case, and the resection margin was unknown, so the indication for endoscopic treatment is unclear.…”