Desmoid tumor is a rare benign tumor derived from fibrous sheath or musculoaponeurotic structure. The tumor is benign histologically but considered as malignant clinically because it has high propensity on infiltrative growth with local invasion and tendency to recurrence after local excision. Especially, when this tumor happens to be in the intra-abdomen, the prognosis is worse because it can cause intestinal obstruction, ureter obstruction and, fistula formation. It also can invade major vessels in abdomen. This tumor occurs more frequently in patients with familial adenomatous polyposis (FAP), in post-partume women, and at old surgical incision site. However, in this case, the patient had neither previous surgery nor a FAP history. We report a rare case of the young male patient who presented with an acute abdomen and underwent laparotomy and was found to have an intra-abdominal desmoid tumor with abscess formation.
Abdominal Abscess/diagnosis ; Adult ; Diagnosis, Differential ; Fibromatosis, Abdominal/*diagnosis/pathology/surgery ; Humans ; Male ; Peritoneal Neoplasms/*diagnosis/pathology/surgery ; Tomography, X-Ray Computed

OBJECTIVETo study the clinicopathologic features, immunophenotype and differential diagnosis of plexiform angiomyxoid myofibroblastic tumor (PAMT) of the stomach.

METHODSThe clinical and pathologic findings of 3 cases of PAMT in the gastric antrum were retrospectively analyzed. Immunohistochemical study was carried out and the literature was reviewed.

RESULTSThe age of patients ranged from 31 to 47 years. The male-to-female ratio was 1:2. The clinical presentation included epigastric pain and distension. Endoscopically, the tumor mass protruded into the gastric cavity at the antrum and ranged from 4.5 cm to 8.0 cm in greatest dimension. One of the tumors studied was associated with surface ulceration. Histologically, the tumors were located in the gastric wall. They were composed of bland spindle cells and small vessels arranged in a plexiform or nodular pattern within a myxoid stroma. Immunohistochemical study showed that the spindle cells were consistently positive for smooth muscle actin and muscle-specific actin. There was focal staining for h-caldesmon, desmin in case 3 and focal positive for epithelial membrane antigen, CAM5.2 in case 1. Further, CD10 and progesterone receptor were positive in case 3.

CONCLUSIONSPAMT represents a rare novel mesenchymal tumor of the stomach, with a propensity of gastric antral involvement. The distinctive pathologic features help to differentiate this entity from other benign and malignant tumors.

Actins ; metabolism ; Adenomyoma ; metabolism ; pathology ; Adult ; Antigens, CD34 ; metabolism ; Diagnosis, Differential ; Female ; Fibromatosis, Abdominal ; metabolism ; pathology ; Follow-Up Studies ; Gastrectomy ; methods ; Gastrointestinal Stromal Tumors ; metabolism ; pathology ; Humans ; Male ; Middle Aged ; Myofibroma ; metabolism ; pathology ; surgery ; Myxoma ; metabolism ; pathology ; surgery ; Proto-Oncogene Proteins c-kit ; metabolism ; Stomach Neoplasms ; metabolism ; pathology ; surgery