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Collision tumour involving a rectal gastrointestinal stromal tumour with invasion of the prostate and a prostatic adenocarcinoma

Laura Macías-García1*, Haydee De la Hoz-Herazo1, Antonio Robles-Frías1, María J Pareja-Megía1, Juan López-Garrido1 and José I López2

Author Affiliations

1 Unidad de gestión clínica de Oncohematología y Anatomía Patológica, Hospital Universitario de Valme, Carretera de Cádiz s/n, 41014, Sevilla, Spain

2 Department of Anatomic Pathology, Hospital Universitario Cruces, Instituto BioCruces, University of the Basque Country, Barakaldo, Bizkaia, Spain

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Diagnostic Pathology 2012, 7:150  doi:10.1186/1746-1596-7-150

Published: 30 October 2012



Gastrointestinal stromal tumours (GISTs) are the most common primary mesenchymal neoplasia in the gastrointestinal tract, although they represent only a small fraction of total gastrointestinal malignancies in adults (<2%). GISTs can be located at any level of the gastrointestinal tract; the stomach is the most common location (60-70%), in contrast to the rectum, which is most rare (4%). When a GIST invades into the adjacent prostate tissue, it can simulate prostate cancer. In this study, we report on a case comprising the unexpected collision between a rectal GIST tumour and a prostatic adenocarcinoma.


We describe the complexity of the clinical, endoscopic and radiological diagnosis, of the differential diagnosis based on tumour biopsy, and of the role of neoadjuvant therapy using imatinib prior to surgical treatment.


Although isolated cases of coexisting GISTs and prostatic adenocarcinomas have previously been described, this is the first reported case in the medical literature of a collision tumour involving a rectal GIST and prostatic adenocarcinoma components.

Virtual slides

The virtual slide(s) for this article can be found here: webcite.

Gastrointestinal stromal tumour; Mixed tumours; Prostatic adenocarcinoma; Imatinib