Plexiform Angiomyxoid Myofibroblastic Tumor of the Stomach

Abstract

Plexiform angiomyxoid myofibroblastic tumor (PAMT) is a recently described gastric tumor with a peculiar plexiform pattern, bland spindle cells and a myxoid stroma rich in arborizing blood vessels. PAMT of the stomach is a very rare tumor without distinctive clinical manifestations. In this study, we report a new case of PAMT which is the first Chinese case in English literature. A 47-year-old Chinese woman was admitted with a 6-month history of intermittent epigastric discomfort, and abdominal pain for 2 months. Gastroscopy showed an elevated mass in the anterior wall of the gastric antrum. Endoscopic ultrasound revealed a focal hypoechoic lesion protruding into the lumen. A laparoscopic distal gastrectomy was performed, and the patient made an uneventful recovery and remains well 1.5 years later. A diagnosis of PAMT was made by histopathology and immunochemistry.

An Update on Clinicopathological and Molecular Features of Plexiform Fibromyxoma

“…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].…”

“…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]. PF cases with severe clinical presentations, such as perforation [1, 21], infection [36], or considerable hemorrhage [53, 58, 63, 74], and with malignant suspicion, such as significant body weight loss [11, 72] or rapid tumor growth [16], should be addressed with aggressive radical surgical treatment rather than conservative management, despite the benign pathological results.…”

Plexiform Fibromyxoma: A Rare Gastric Tumor

“…Only few cases have been reported so far since the first case described in 2007 by Takahashi et al [ 1 ]. Until October 2016, only 19 immunohistochemically confirmed cases have been reported in the literature [ 3 ].…”

“…Plexiform fibromyxoma is a recently described gastric tumor with peculiar plexiform pattern, bland spindle cells, and a myxoid stroma invading the blood vessels [ 1 ]. The tumor almost exclusively occurs in the gastric antrum and may extend into the extra gastric soft tissues or into the duodenal bulb [ 2 , 3 ]. Histologically, typical plexiform intramural growth has multiple micronodules containing paucicellular to moderately cellular myxoid to collagenous and fibromyxoid neoplastic elements [ 4 ].…”

“…Frequent ulceration and mucosal and vascular invasion with no adverse significance are seen in these tumors [ 5 ]. Immunohistochemically the tumor cells are positive for α smooth muscle actin (SMA) and variable for CD10 and consistently negative for KIT, DOG1, CD34, Desmin, and S100 protein [ 1 , 3 , 6 ]. No KIT or platelet-derived growth factor receptor alpha mutations are present [ 2 ].…”