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

Adenocarcinoma ; pathology ; Adenomatoid Tumor ; metabolism ; pathology ; surgery ; Adenomyoma ; pathology ; Adult ; Antibodies, Monoclonal, Murine-Derived ; metabolism ; Biomarkers, Tumor ; metabolism ; Calbindin 2 ; metabolism ; Diagnosis, Differential ; Female ; Follow-Up Studies ; Humans ; Keratins ; metabolism ; Leiomyoma ; pathology ; Lymphatic Vessel Tumors ; metabolism ; pathology ; Middle Aged ; Uterine Neoplasms ; metabolism ; pathology ; surgery ; Young Adult

BACKGROUND/AIMS: Ampullary adenomyoma is a benign lesion whose malignant potential has yet to be confirmed. Despite its benign nature, adenomyoma is frequently misdiagnosed as a carcinoma or adenoma and is overtreated by extensive surgery. This study was performed to analyze the clinical, pathological, and immunohistochemical features of adenomyomas in the ampulla of Vater. METHODS: Nine cases of adenomyoma in the ampulla of Vater, diagnosed in Chungbuk National University Hospital between 2008 and 2011, were enrolled in this study. We reviewed the clinical data on the symptoms, laboratory data, and radiologic findings of the abdominal computed tomography and endoscopic retrograde cholangiopancreatography. For pathological analysis, all the slides were reviewed by one pathologist, and immunohistochemical stainings with antibodies against cytokeratin 7 (CK7), cytokeratin 20 (CK20), alpha-smooth muscle actin (alpha-SMA), and Ki-67 antigen were performed. RESULTS: All the cases were CK7 positive and CK20 negative. A strong cytoplasmic expression of alpha-SMA was confirmed in all cases. The Ki-67 index was less than 1% in eight cases and 5% in one case. Four cases underwent endoscopic papillectomy, and one case received surgical ampullectomy during colorectal cancer surgery. Five cases that underwent endoscopic or surgical treatment remained symptom-free for three years. Four cases that were closely observed with repeated endoscopic examinations exhibited no interval changes in the papillary lesions. CONCLUSIONS: Endoscopic biopsy and immunohistochemistry can aid in the diagnosis of ampullary adenomyomas. Endoscopic papillectomy or surgical ampullectomy is adequate for the treatment of symptomatic ampullary adenomyomas.
Actins/metabolism ; Adenomyoma/*pathology/surgery ; Aged ; Ampulla of Vater/*pathology ; Cholangiopancreatography, Endoscopic Retrograde ; Common Bile Duct Neoplasms/*pathology/surgery ; Female ; Humans ; Immunohistochemistry ; Keratin-20/metabolism ; Keratin-7/metabolism ; Ki-67 Antigen/metabolism ; Male ; Middle Aged ; Retrospective Studies ; Tomography, X-Ray Computed ; Treatment Outcome