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 NUNZIA SCIBETTA - LORENZO MARASA’ Department of Pathology, A.R.N.A.S. Civico, Palermo

2. INTRODUCTIONINTRODUCTION  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.  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. METHODSMETHODS  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.  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. RESULTSRESULTS  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.  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. Intestinal–type, gastric adenocar- cinoma: immunoreactivity for CKAE1 1 2 2 3 1 23 2 3 1. Intestinal-type, gastric adenocar- cinoma

6. 3. Intramuscolar- subserosal gastric nodule 1 2 2 3 1 23 2 3 4. The tumor is composed of epithe- lioid cells with clear cytoplasm 34

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. VimentinCD117CD34

8. CONCLUSIONSCONCLUSIONS  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 MAIN REFERENCE Maiorana A. et al.- Arch Pathol Lab Med 124 : 682 – 686 ; Maiorana A. et al.- Arch Pathol Lab Med 124 : 682 – 686 ; 2000. 2000.  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 MAIN REFERENCE Maiorana A. et al.- Arch Pathol Lab Med 124 : 682 – 686 ; Maiorana A. et al.- Arch Pathol Lab Med 124 : 682 – 686 ; 2000. 2000.