Gastrointestinal stromal tumors (GIST).

BACKGROUND/AIMS: Gastrointestinal stromal tumors (GIST) are the most frequent non-epithelial tumors of the alimentary tract. The interstitial cells of Cajal or more primitive progenitor mesenchymal cells are suggested as their cells of origin. GIST's occur throughout the gastrointestinal tract but are generally located in the stomach and the intestine. About 70% of GIST's are immunohistochemically positive for CD34 and more than 90% for c-kit protein (CD117). About two thirds of GIST's are malignant. The tumor size, mitotic rate, cellularity and nuclear pleomorphism are the most important parameters characterizing the biological behavior of tumors. The diagnostic procedures are similar to those of other gastrointestinal neoplasms but only a half of the patients will have correct preoperative histological diagnosis. GIST's can be cured only by surgery. The procedure of choice, if possible, is resection without extended lymphadenectomy. Radiation and chemotherapy are generally ineffective. METHODOLOGY: 22 patients were operated on for GISTs in our department between 1996 and 2003. RESULTS: All but one proved to be benign. The patients were all asymptomatic after the operation except the malignant case. In his case an irresectable local recurrence developed later. CONCLUSIONS: GIST is a rare neoplasm of the GI tract. The only possibility for treatment of GISTs is surgical removal.

[A case of ossifying fibromyxoid tumor]. / Ossificaló fibromyxoid tumor esete.

Recently described entity: ossifying fibromyxoid tumour of soft parts is presented. Schwann cell nature of the proliferating cells was demonstrated by immunohistochemical means. This special kind of nerve sheath tumors is characterised by pathological differentiation of the cells, resulting bone and in some cases additional cartilage formation. As for biological behaviour: in spite of occasional histological evidences of malignancy, no distant metastases are to be expected. Local aggressivity and recurrences may occur, thus designation is preferable as semimalignant or according to more modern terms as low-grade malignant tumour.

Distribution of calcitonin-containing parafollicular cells of the thyroid in patients with chronic lymphocytic thyroiditis: a clinical, pathological and immunohistochemical study.

The C-cell hyperplasia of the thyroid gland is recognized as precursor to medullary carcinoma, particularly in multiple endocrine neoplasias, however it can be associated with hypercalcemic states and follicular tumours as well. The authors analysed 46 of their cases with Hashimoto's and/or lymphocytic thyroiditis from the immunohistological point of view with the aim of determining to what extent is C-cell hyperplasia associated with these pathological pictures. C-cell hyperplasia was demonstrated on sections of intraoperative preparations with the immunoperoxidase method with anticalcitonin MoAb. Moderate, focal C-cell hyperplasia was found in 17.4% (8 patients), extensive focal hyperplasia similarly in 17.4% (8 patients). Diffuse C-cell hyperplasia occurred in 1 case (2.2%). These results suggest the possibility that in the case of diffuse or more pronounced focal hyperplasia the serum calcitonin concentration of these patients is also elevated. Further clinical and pathological studies are needed to find out whether there is some pathogenetic relationship between chronic lymphocytic thyroiditis and C-cell hyperplasia or whether the finding is coincidental, and to establish what degree of C-cell hyperplasia is associated with elevated serum calcitonin levels. This relationship has been unknown until the present time, whereas it can be of great clinical significance, in part because of the changes in serum calcitonin levels, in part for screening out the MEN IIa type and working out the operating strategy.

[Aspiration cytology in the diagnosis of gastrointestinal tumors]. / A tápcsatorna daganatainak aspirációs citológiai vizsgálatáról.

Early experiences with the new endoscopic aspiration cytology method in the diagnosis of gastrointestinal malignancies are discussed. It was performed in five patients in case of gastric and cardiac cancers and in fifteen ones of colon tumours. Results are compared with those of biopsies and brush cytologies. The new method is quick, reliable and suggested to be widely used in the gastrointestinal endoscopy.