Oncocytoma and Oncocytic Carcinoma of the Salivary Glands, Single Institute Experience

BACKGROUND: Oncocytic neoplasms of the salivary glands are rare and the differential diagnosis between oncocytic carcinomas (OCs) and oncocytomas is difficult. We present 5 cases of oncocytoma and 3 cases of OC of the salivary glands with clinicopathological and immunohistochemical comparisons. METHODS: Eight cases of oncocytic neoplasms diagnosed at Asan Medical Center between 1998 and 2009 were reviewed for clinical data and histological features. Immunohistochemical staining for epidermal growth factor receptor (EGFR), human epidermal growth factor receptor 2 (Her-2), c-kit, p53, and Ki-67 was done. RESULTS: Cytological differences between oncocytomas and OCs were not obvious, but unequivocal infiltrative growths were identified in 3 cases, rendering the diagnosis of oncocytic carcinoma. When the remaining cases were classified as oncocytomas, there was no difference in age, size, and clinical symptoms between oncocytomas and OCs. Two of 3 OCs showed strong membranous expression of c-kit, but all oncocytomas were negative. The proportion of p53-positive cells was larger in OCs than oncocytomas. Her-2 or EGFR expression was absent, and Ki-67 labeling indices were less than 1% in all cases. CONCLUSIONS: An infiltrative growth pattern, strong membranous expression of c-kit, and an increased proportion of p53-positive cells are features that can differentiate OCs from oncocytomas of the salivary glands.

c-kitMutation and Immunohistochemical Expression in Gastrointestinal Stromal Tumors

BACKGROUND: Gastrointestinal stromal tumor (GIST) is the most common non-epithelial neoplasm arising in the gastrointestinal tract. The aim of this study is to investigate the correlation among the clinicopathologic features, presence of c-kit mutation, and immunohistochemical expression of c-kit in 61 cases of GISTs. METHODS: We divided the GISTs into three groups as benign, boderline and malignant, according to histologic grade. Exon 11 of the c-kit was amplified by PCR and sequenced. We performed immunohistochemical study for CD117, CD34, vimentin, SMA, desmin, and S-100 protein. RESULTS: Twenty-one cases were diagnosed as benign GISTs, 14 cases as borderline GISTs, and 26 cases as malignant GISTs. The shape, atypia, cellularity, and necrosis showed good correlations with the histologic grades of the GISTs.Mutations of exon 11 of the c-kit were detected in 3 benign GISTs, 4 borderline GISTs, and 13(%) malignant GISTs. Sequence analysis confirmed the deletion mutation (n=16) and the singlebase pair mutation (n=4). The immunohistochemical stainings showed myogenic differentiation(n=20), neurogenic differentiation (n=15), and neither myogenic or neurogenic differentiation(n=34). CONCLUSIONS: The GIST is the primitive mesenchymal tumor capable of divergent differentiation, and the mutation of the c-kit is a good parameter for the malignant GIST.

A Clinical and Immunohistochemical Study on Gastrointestinal Stromal Tumor / 대한소화기학회지

BACKGROUND/AIMS: As the relationship between gastrointestinal stromal tumors (GIST) and interstitial cells of Cajal had become clear, GIST is defined as CD117 positive mesenchymal tumors, and recognized as a new distinct entity among mesenchymal tumors presenting as gastrointestinal submucosal tumors (SMT). To evaluate GISTs in the category of SMTs, we analyzed mesenchymal SMTs immunohistochemically and clinicopathologically. METHODS: Forty-five patients with mesenchymal SMTs, who received surgical or endoscopic resection were retrospectively analyzed for clinical parameters. Immunohistochemical staining for CD117, CD34, NSE, SMA, and S-100 was also performed. RESULTS: Among 45 tumors, 41 (91.1%) expressed CD117 and were diagnosed as GIST. The most frequent location was the gastric body. Except esophageal location (73.3%), GISTs accounted for 100% of SMTs in the gastrointestinal tract. The mixed myoid-neural differentiated type and the spindle cell shape were most common. Metastasis was observed in 5 patients (11%). All of them had tumors larger than 5 cm and died. Their mean survival was 4.6 months. CONCLUSIONS: GIST accounted for majority (91.1%) of SMTs. The presence of metastasis and tumor size at the time of diagnosis indicate poor prognostic factors. Immunohistochemical study is necessary for exact diagnosis of GIST.