[5] Estimated frequency of PAMT is less than 1/150 compared to that of gastrointestinal stromal tumors (GISTs).
PAMT is considered as a benign tumor, due to its histological features such as the presence of bland tumor cells, low proliferation index, low mitotic-rate, absence of necrosis and vascular invasion and no recurrence.
Most patients present certain symptoms including anaemia due to hematemesis, ulceration, gastric outlet obstruction, fistulating abscess formation, intermittent epigastric discomfort and abdominal pain, nausea, vomiting, weight loss, or could be asymptomatic with incidental finding.
[7] Immunohistochemically, the tumour cells show positive staining for vimentin and smooth muscle actin (SMA).
The tumour cells are generally negative for CD117, DOG1, SMA, Caldesmon, CD34, Epithelial membrane antigen (EMA), Cytokeratin or Anaplastic lymphoma kinase (ALK).
[5] Microscopically, the gastric wall shows a characteristic multinodular plexiform pattern of the tumour.
[11] Further studies could provide more information about its histogenesis and molecular signature that could be applied in targeted therapeutic approach.