[Stromal tumor of the ileum (GIST) at the same time as a renal carcinoma. Description of a case and review of the literature].

The gastrointestinal mesenchymal tumors from a heterogenous group that include several entities: leiomyomas, schwanomas and less differentiated tumors often referred as GIST. These neoplasm are uncommon and their clinical behaviour is most difficult to predict. We describe a malignant gastrointestinal stromal tumor of the ileum coexisting with renal cell carcinoma. The neoplasms were fixed in formaldehyde, embedded in paraffin and stained with hematoxylin-eosin. For immunohistochemical studies deparaffinized tissue sections were incubated with antibodies against vimentin, desmin, muscle specific actin, S100, CD34, GFAP, NSE and keratin. The epithelioid and spindle cells of ileal neoplasm were arranged in interlacing fascicle with occasional palisading and were positive for vimentin and CD34. Positivity for muscle specific actin was focally found. The renal neoplasm required differential diagnosis from metastatic GIST. The morphological and immunohistochemical investigations in our case were consistent with GIST coexisting with primitive renal cell carcinoma. One of the problems connected to the anatomo-clinical evaluation of GIST consist in the difficulty of making a prognosis. An almost complete review of the literature and view point on the topic has been performed. As a conclusion judging from papers regarding this argument, no clear parameters of biological behaviour exist excluding mitotic index.