An exceptional collision tumor: gastric calcified stromal tumor and pancreatic adenocarcinoma

An exceptional collision tumor: gastric calcified stromal tumor and pancreatic adenocarcinoma

Hicham Baba^1,&, Mohamed Elfahssi¹, Mohamed Said Belhamidi¹, Abderrahman Elhjouji¹, Ahmed Bounaim¹, Abdelmounaim Ait Ali¹, Khalid Sair, Aziz Zentar¹

¹Departement of surgery I, Mohamed V Teaching Military Hospital, Rabat 10100, Morocco

^&Corresponding author
Hicham Baba, Departement of surgery I, Mohamed V Teaching Military Hospital, Rabat 10100, Morocco

The collision tumor is defined as the existence of two different histologic types of carcinoma that are either contiguous or intermingled.

The patient was a 70-year-old male who presented with a 6-month history of vomiting, epigastric pain and weight loss. A gastroscopy revealed a large submucosal lesion originating in the fundus of the stomach and the biopsies were inconclusive. CT study revealed a 12x10x9 cm partially calcified mass with heterogeneous contrast enhancement on the fundal region and greater curvature of the stomach (Figure 1). The patient underwent a total gastrectomy associated to a distal splenopancreatectomy and segmental transverse colectomy (Figure 2). The final pathologic diagnosis was collision tumor of gastric GIST and pancreatic adenocarcinoma (Figure 3, Figure 4).

Collision tumor has been defined as two histologically differing tumors simultaneously involving the same organ with an equivocal intermediate transitional zone between them [1]. Our patient presents an exceptional case of collision tumor between two tumors arising from different organs. One case of an adenocarcinoma of the head of the pancreas associated with a low grade gastric stromal tumor was reported; however, the exact location of the gastric tumor was not specified [2]. Otherwise, the synchronous occurrence of GISTs and other primary tumors is considered an uncommon entity however such occurrence has been more frequently described in literature mainly in form of single case reports. This situation is almost always discovered incidentally as during surgery or staging exams of the primary disease. Further, GISTs have been reported to occur synchronously mostly with adenocarcinoma. Among the assumptions that have been invoked to explain synchronicity is that the environmental carcinogens might affect molecular pathways that are shared by mesenchymal and epithelial cells of the digestive tract [3]. The other particularity of our observation is GIST´s calcification which is not a usual clinicopathologic feature of this type of tumor. In a series of 29 cases, there are only three primary GISTs containing foci of calcification (10.3%) [4, 5].

If collision tumor in the same organ is uncommon and usually discovered incidentally; it is exceptional when it occurs between two tumors of adjacent organs.

The authors declare no competing interests.

All authors read and approved the final version of the manuscripts.

Figure 1: partially calcified mass with heterogeneous contrast enhancement on the fundal region and greater curvature of the stomach

Figure 2: specimen of resection

Figure 3: zone of collision between the gastric stromale tumor (left) and the pancreatic adenocarcinoma (right) (HEx40)

Figure 4: CD117 expression in stromal gastric tumor (x 10)

1. Bhagirath Majmudar, Robert Dillard, Philip William Susann. Collision carcinoma of the gastric cardia. Human Pathology. 1978; 9(4):471-473. PubMed | Google Scholar


2. M'sakni Issam, Rammeh S, Chelbi E, Sayari S, Zaouech A, Baltagi-Ben Jilani S, Zermani R. Adénocarcinome et tumeur stromale digestifs : association fortuite ou mécanisme oncogène commun? À propos de deux observations. Annales de Chirurgie. 2006 ; 131(8) :464-467. PubMed | Google Scholar


3. Ferreira Sheila S, Werutsky Gustavo, Toneto Marcelo Garcia, Alves Jarcedy Machado, Piantáemail Christina Duarte, Breunig Raquel Cristine, Brondani da Rocha Adriana, Griviciche Ivana, Garicochea Bernardo. Synchronous gastrointestinal stromal tumors (GIST) and other primary cancers: case series of a single institution experience. International Journal of Surgery. 2010; 8(4): 314-317. PubMed | Google Scholar


4. Kim C, Day S, Yeh K. Gastrointestinal stromal tumors: analysis of clinical and pathologic factors. Am Surg. 2001; 67(2):135-137. PubMed | Google Scholar


5. Lau S, Tam KF, Kam CK, Lui CY, Siu CW, Lam HS, Mak KL. Imaging of gastrointestinal stromal tumour (GIST). Clinical Radiology. 2004; 59(6): 487-498. PubMed | Google Scholar