Background: The aim of study was to determine the relative frequency of malignant lymphoma according to World Health Organization (WHO) classification in Korea. Methods: A total of 3,998 cases diagnosed at 31 institutes between 2005 and 2006 were enrolled. Information including age, gender, pathologic diagnosis, site of involvement and immunophenotypes were obtained. Results: The relative frequency of non-Hodgkin lymphoma (NHL) and Hodgkin lymphoma (HL) was 95.4% and 4.6%, respectively. B-cell lymphomas accounted for 77.6% of all NHL, while T/ natural killer (T/NK)-cell lymphomas accounted for 22.4%. The most frequent subtypes of NHL were diffuse large B-cell lymphoma (42.7%), extranodal marginal zone B-cell lymphoma (MZBCL) of mucosa-associated lymphoid tissue (19.0%), NK/T-cell lymphoma (6.3%) and peripheral T-cell lymphoma (PTCL), unspecified (6.3%), in decreasing order. The relative frequency of HL was nodular sclerosis (47.4%), mixed cellularity (30.6%), and nodular lymphocyte predominant (12.1%) subtypes. Compared with a previous study in 1998, increase in gastric MZBCL and nodular sclerosis HL, and slight decrease of follicular lymphoma, PTCL, and NK/T-cell lymphoma were observed. Conclusions: Korea had lower rates of HL and follicular lymphoma, and higher rates of extranodal NHL, extranodal MZBCL, and NK/T-cell lymphoma of nasal type compared with Western countries. Changes in the relative frequency of lymphoma subtypes are likely ascribed to refined diagnostic criteria and a change in national health care policy.

The signal transducer and activator of the transcription (Stat)-family of proteins are latent cytoplasmic transcription factors that transmit signals from cytokines and growth-factor receptors to the nucleus. Stat proteins, especially Stat3 and Stat5, are constitutively activated in various solid tumors and hematological malignancies. However, the role of Stat3 signaling in gastric carcinoma has not yet been fully determined. This study was conducted to investigate the clinical value of phospho-Stat3 expression in gastric carcinoma. Expression of phospho-Stat3 (Tyr705), vascular endothelial growth factor (VEGF), p53, and Bcl-2 was determined by immunohistochemical staining of tissue microarrays from 137 cases of resected gastric cancer specimens. We evaluated the relationships among phospho-Stat3, VEGF, p53, and Bcl-2 expression and the correlation between expression of these proteins and various clinicopathological factors, including overall survival. Phospho-Stat3 nuclear expression was observed in 18.2% of the cases. Of the total number of cases, 68.6% were positive for VEGF, 40.1% for p53, and 11.7% for Bcl-2. Phospho-Stat3 expression correlated with VEGF (p=0.021) and Bcl-2 (p=0.005) expression. Positive phospho-Stat3 staining was significantly associated with poor pathological grade. However, there was no significant difference in other clinicopathological parameters, such as tumor stage (T, N, M), pathological type, relapse-free survival, and overall survival between the phospho-Stat3-positive and -negative groups. Co-expression of phospho-Stat3 and VEGF was found in many patients with N3 and Stage IV disease. These results suggest that phospho-Stat3 expression might be associated with angiogenesis, anti-apoptosis, and tumor progression. Further studies are needed to determine the role of phospho-Stat3 in gastric cancer.

Mucoepidermoid carcinoma of the liver is a rare variant of cholangiocarcinoma, containing both mucus-secreting glandular cells and squamous cells mixed in nests. We report a case of mucoepidermoid carcinoma of the liver in a 69-year-old woman who presented with a 1-week history of fever, chills, and right flank pain. On admission, she was not jaundiced, and under a provisional diagnosis of liver abscess, a pigtail catheter was inserted into the abscess cavity. We performed right hepatectomy and partial excision of the diaphragm 1 month later. Microscopically, the tumor was composed of solid and invasive nests of epidermoid and mucin-producing cells with desmoplastic stroma. The epidermoid component of the tumor contained intercellular bridges and individual cell keratinization. Alcian blue and Periodic acid-Schiff (PAS) staining confirmed that there was mucin in the cytoplasm of mucus-secreting cells. The tumor cells, intrahepatic bile ducts, and ductules were consistently reactive with cytokeratin (CK) 7 and negative for CK20. The adjacent nonneoplastic liver cells were CK 7-/CK20-, and P63 immunostaining was positive in the epidermoid cells. The tumor was diagnosed as mucoepidermoid carcinoma arising from the intrahepatic bile duct. Despite aggressive surgical treatment, the patient died of multiple liver metastases 4 months after the right hepatectomy.

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Fifty three bile specimens from 42 patients were reviewed to assess the diagnostic role of the bile cytology and to define more reliable cytologic indicators of malignancy. Forty three bile specimens came from 34 patients with malignant biliary strictures and 10 bile specimens were from eight patients with benign conditions. There were no false positives. The diagnostic specificity of bile cytology was 100% while diagnostic sensitivity was 55.8%. Overall diagnostic accuracy was 64.2%. We identified four key criteria as cytologic indicators of malignancy among 20 variables by using multiple regression analysis: loss of honeycomb arrangement, hyperchromatism, increased N/C ratio, and coarse chromatin. When bile specimens with three or more of these four criteria are thought to represent malignancy, the sensitivity of diagnosis of malignancy was 65.2%, specificity was 90% and diagnostic accuracy was 69.8%.