Plexiform angiomyxoid myofibroblastic tumor of the stomach

Abstract

Plexiform angiomyxoid myofibroblastic tumor of the stomach is a unique mesenchymal tumor that we first described in 2007. The tumor is very rare, and to date, only 18 cases confirmed by immunohistochemistry have been reported in the literature. The patients' ages ranged from 7 to 75 years (mean, 43 years), and the male-to-female ratio was approximately 1:1. Representative clinical symptoms are ulceration, associated upper gastrointestinal bleeding (hematemesis), and anemia. The tumors are located at the antrum in all cases, and grossly, the tumor is whitish to brownish or reddish, and forms a lobulated submucosal or transmural mass. Microscopically, the tumor is characterized by a plexiform growth pattern, the proliferation of cytologically bland spindle cells, and a myxoid stroma that is rich in small vessels and positive for Alcian blue stain. Immunohistochemically, the tumor cells are positive for alpha-smooth muscle actin and negative for KIT and CD34. Differential diagnoses include gastrointestinal stromal tumor and other mesenchymal tumors of the gastrointestinal tract. Some authors proposed that this tumor should be designated as "plexiform fibromyxoma", but this designation might cause confusion. The tumor is probably benign and thus far, neither recurrence nor metastasis has been reported.

Plexiform Angiomyxoid Myofibroblastic Tumor (PAMT) of Stomach with Synchronous Bilateral Cystic Ovarian Neoplasms, a Rare Case Presentation

“…Two years later, Miettinen et al described a series of similar tumors, and they advocated the use of the appellation "plexiform fibromyxoma" and estimated that the frequency of PAMT is less than 1/150 that of GIST [4,5]. Till now only 29 cases of Plexiform Angiomyxoid Myofibroblastic Tumour (PAMT) have been reported, including our present case .The prevalence rate of PAMT are not dependent upon the gender with almost equal distribution among the sexes (M:F=13:16).The average tumor size varies in range (1.5-15 cm), but most are a few cm in size (mean: 6.0 cm) [1,2].…”

“…However, the bland nuclear features, low proliferative index and absence of necrosis, vascular invasion, recurrence or metastasis in all PAMT cases reported to date justify its characterization as a benign tumor [2,4] but association of this with cystic ovarian disease is of true concern. Currently, complete excision remains the treatment of choice [1].…”

“…Plexiform Angiomyxoid Myofibroblastic Tumor (PAMT) is a recently identified mesenchymal tumor of the stomach, which was first described in the year 2007 and was added in the 2010 WHO classification of tumors of the digestive system [1]. It closely resembles with other gastric tumors but distinctly varies in clinical management as well as the histopathology and immunohistochemistry.…”

Management of Gastrointestinal Stromal Tumour: Current Practices and Visions for the Future

“…GIST was excluded, and the patient was diagnosed with a plexiform angiomyxoid myofibroblastic tumour of the stomach. This is a very rare tumour that, although entirely benign, has a high tendency to bleed and can therefore be life-threatening [50,51]. a Low-power view of a plexiform angiomyxoid myofibroblastic tumour of the stomach.…”

Gastric plexiform angiomyxoid myofibroblastic tumour

“…6 PAMT classically occurs in the antro-pyloric region of the stomach with a wide range of age distribution (7e75 years) with a mean age group of 43 years. 9 Male and females are equally affected. 9 The presenting clinical features are related to the either the mass effect i.e., gastric outlet obstruction such as epigastric pain, nausea, emesis, weight loss or due to ulceration of the overlying mucosa.…”