J Gastric Cancer.  2017 Sep;17(3):277-281. 10.5230/jgc.2017.17.e22.

Plexiform Angiomyxoid Myofibroblastic Tumor of the Stomach: a Rare Case

• Kim SM
• An JY
• Choi MG
• Lee JH
• Sohn TS
• Kim KM
• Kim S
• Bae JM

• KMID: 2389832
• DOI: http://doi.org/10.5230/jgc.2017.17.e22

Abstract

Plexiform angiomyxoid myofibroblastic tumor (PAMT) of the stomach is a very rare mesenchymal tumor of the gastrointestinal tract. We report a case of asymptomatic gastric PAMT that was pathologically confirmed after surgical resection. The tumor had a multinodular plexiform growth pattern, bland-looking spindle cells, and an Alcian blue-positive myxoid stromal matrix rich in small blood vessels. Immunohistochemistry analysis revealed that the tumor cells of the PAMT were positive for smooth muscle actin (SMA) and negative for c-kit, CD34, S-100 protein, epithelial membrane antigen (EMA), and desmin. PAMT should be differentiated from other submucosal tumors of the stomach by immunohistochemical findings. Considering the benign features of this tumor, observation without resection may be an option for the treatment of PAMT if the tumor is asymptomatic.

Keyword

Stomach; Neoplasms; Mesenchymal tumor

MeSH Terms

Actins
Blood Vessels
Desmin
Gastrointestinal Tract
Immunohistochemistry
Mucin-1
Muscle, Smooth
Myofibroblasts*
S100 Proteins
Stomach*
Actins
Desmin
Mucin-1
S100 Proteins

Figure

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  Fig. 1 Esophagogastroduodenoscopy shows a smooth, normal mucosa-covered elevated lesion at the gastric antrum.

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  Fig. 2 Computed tomography shows a well-marginated cystic lesion, suspected to be a GIST, glomus tumor, or neuroendocrine tumor. GIST = gastrointestinal stromal tumor.

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  Fig. 3 (A) Tumor surgically removed by laparoscopic wedge resection. Cut section shows a well-defined whitish and firm mass. (B) Tumor demonstrates infiltrative growth of cellular areas into smooth muscle bundles in the muscularis propria. (C) Tumor shows loose myxoid areas (left part) and cellular areas (right part) admixed with smooth muscle cells. (D) Smooth muscle fibers and tumor cells positive for smooth muscle actin (×200). (E) Tumor cells negative for c-kit. Mast cells were positively stained as an internal positive control (arrows).

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