engleski

Review of Gastrointestinal Stromal Tumors in 2005-2015: A Single-Center Experience

Background: Gastrointestinal stromal tumor (GIST) is a very rare tumor type, although it is the most common primary mesenchymal tumor of the gastrointestinal tract (GIT). It's clinical spectrum spans from benign to malignant. Biopsy and immunohistochemical staining (IHS) are crucial for differentiation GISTs from other mesenchymal masses in GIT. Aim: To contribute to the collection of pathohistological data of GISTs such as dimension, localization, mitotic rate, malignant potential and immunohistochemical charachteristics. Also to present the sensitivity of IHS with DOG1. Materials and methods: UHC Rijeka provided pathohistological and immunohistochemical data of GIST biopsies from 2005 to 2015. Basic statistic was used to represent consequiental features of this tumor type. Results: Altogether, biopsy was performed on 89 patients and their mean age was 62.9±14.0. 43 patients (48.3%) were male and 46 (51.7%) were female. Most GISTs (48.3%) were localized in stomach. Other localizations were: small intestine (36.0%), large intestine (6.7%), rectum (4.5%), retroperitoneum (3.4%) and omentum (1.1%). The mean dimension was 6.34±4.63 cm. Most GISTs were histologically charachteristic spindle cell tumors (84.3%), while epithelioid (3.4%) and mixed histology (12.3%) were less common. Malignant potential was found in 33.7% of tumors, 65.2% tumors were benign, while 1.1% had insecure malignant potential. Low mitotic rate (< 5 mitoses) was present in 67.4% GISTs and 32.6% had high mitotic rate (> 5 mitoses). The most specific antibody in IHS is DOG1, which is used in our center since 2012. 25 GISTs were stained with DOG1 to confirm the diagnosis and this antibody has given 100% positive result. Conclusion: IHS (CD117, vimentin and especially DOG1) is unavoidable to differentiate GIST from other mesenchymal tumors such as leiomyoma, leiomyosarcoma, schwannoma and synovial sarcoma. When GIST diagnosis is allocated it is of high importance to classify tumor's prognostic group, based on prognostic factors such as tumor size and mitotic rate, which directs further treatment protocol.

gastrointestinal stromal tumor; immunohistochemical staining; spindle cells; mitotic rate; prognostic group

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