SYNCHRONOUS ADENOCARCINOMA AND STROMAL TUMOR OF THE STOMACH : A CASE REPORT.

1. SYNCHRONOUS ADENOCARCINOMA AND STROMAL TUMOR OF THE STOMACH : A CASE REPORT. NUNZIA SCIBETTA - LORENZO MARASA’ Department of Pathology, A.R.N.A.S. Civico, Palermo

2. INTRODUCTION • The simultaneous development of gastric mesen-chymal tumor and adenocarcinoma has been rarely documented in the literature. • The majority were reported in the Japanese literature and regard coexistent adenocarcinoma and leiomyo-ma or leiomyosarcoma of the stomach. • Recently, Maiorana et al [2000] report 6 cases with syn-chronous occurrence of epithelial and stromal tumors in the stomach. • We report a case of synchronous occurrence of ga-strointestinal stromal tumor (GIST) and adenocarcino-ma located in different regions of the stomach.

3. METHODS • A 88-year-old woman , with nausea and abdominal di-scomfort was subjected to esophago-gastro-duodeno-scopy, that showed a polypoid mass located on the an-trum. On small biopsy fragments, a pathologic diagno-sis of adenocarcinoma was rendered. She no showed family history of cancer. Abdominal computed tomogra-phic scans and thoracic radiographs performed had di-sclosed no metastatic deposits. • Partial gastrectomy was performed. Specimens had been fixed in 4% formaldehyde and embedded in para-plast. Sections were stained with H&E. • Immunohistochemistry was performed using a panel of antibodies directed against the following antigens:EMA, vimentin, desmin, muscle-specific actin, S100 protein, CD34, CD117, KI 67.

4. RESULTS • Grossly the stomach showed a polypoid, ulcerated mass of 5 cm of largest diameter located in the antrum, and a 0,5 cm, subserosal nodule, on section well-circumscribed, with smooth appearance, located in the lesser curvature. • Microscopic examination revealed that the exophytic mass was an intestinal-type adenocarcinoma infiltrating the submucosa, and the subserosal nodule was a GIST with epithelioid cells, with clear cytoplasm and well-defined cell membranes.The non neoplastic gastric mucosa showed chronic gastritis.

5. 2 1 1 2 1 . Intestinal-type, gastric adenocar- cinoma 2 . Intestinal–type, gastric adenocar-cinoma:immunoreactivity for CKAE1 3 2 3 3 2

6. 1 2 2 1 3 4 3 . Intramuscolar- subserosal gastric nodule 4 . The tumor is composed of epithe-lioid cells with clear cytoplasm 3 2 3 3 2

7. IMMUNOHISTOCHEMICAL EXAMINATION • Immunohistochemical reactions in the GIST were diffusely positive for CD34 and vimentin, focally positive for CD117, negative for EMA, S100 protein, desmin, muscle-specific actin. The mitoses were <5 mitoses/50HPF. Vimentin CD34 CD117

8. CONCLUSIONS • This coexistence of epithelial and stromal gastric tumor raises the question of whether such an occurrence is a simple incidental association, or the 2 lesions are connected by a causal relationship. Gene mutations might underlie tumor predisposition in patients harbouring a double gastric neoplasia, at present, however, no data are available to support this hypothesis. • A tumorigenic agent interacting with 2 neighboring tissues could produce development of tumors of different histotypes in the same organ and experimental evidence for this possibility has been provided. • Investigating the molecular alterations in cases such as this one will possibly shed interesting light on the mechanism of tumorigenesis. MAIN REFERENCE Maiorana A. et al.- Arch Pathol Lab Med 124 : 682 – 686 ; 2000.