High mast cell density associated with granulomatous formation in tuberculous lymphadenitis.

Mast cells are one of the main inflammatory cells involved in the pathogenesis of tuberculosis. Previous reports revealed that mast cells participated in both acute and chronic states of infection with Mycobacterium tuberculosis through direct contact or indirect enhancement by releasing mediators. The authors evaluated mast cell density on tissue sections of tuberculous lymphadenitis stained with 0.1% toluidine blue from 45 cases, all of which were retrieved from the surgical pathology files of King Chulalongkorn Memorial Hospital from 1999 to 2006. A number of mast cells were correlated semiquantitatively with granulomas which were formed by aggregation of epithelioid histiocytes, multinucleated giant cells, and caseous necrosis. We found that mast cell density was significantly increased in lymph nodes with greater granuloma involvement (p = 0.030) and multinucleated giant cell formation (p = 0.010). These findings indicate a significant correlation between mast cell density and the granulomatous formation responsible for M. tuberculosis.

RET proto-oncogene expression of papillary thyroid carcinomas in Thai patients.

BACKGROUND: Ret proto-oncogene activation has been found in papillary thyroid carcinoma with different frequencies according to geographic location. The rate of expression ranges from 0-100 percent in the literature. This gene expression has also been studied in many Asian countries but it has never been studied in Thailand. OBJECTIVE: To study the frequency of the RET expression and their roles in predicting prognosis of papillary thyroid carcinoma among Thai patients treated at King Chulalongkorn Memorial Hospital, Bangkok, Thailand. MATERIAL AND METHOD: One hundred and one cases of papillary carcinomas were studied with immunohistochemistry for RET antibodies. All slides with routine staining were reviewed to classify cell variants and record other prognostic parameters such as size, multicentricity, extrathyroid invasion. The clinical data such as age and sex were also included for analyses. RESULTS: Forty-seven of the total 101 cases (46.5%) showed positive RET protein staining. The mean age among patients with RET negative neoplasms was 43.9 years compared with 39.8 years in RET positive group (p = 0.16). The average size of the tumors without RET expression was 2.5 cm, slightly larger than the RET positive tumors (2.1 cm)(p = 0.26). Extrathyroid invasion of the RET-positive tumors was found to be 33.2 percent while the RET negative neoplasms had 38.8 percent of this feature (p = 1). According to AMES score, the RET positive cases had only 11 percent of high-risk tumors, whereas the RET negative group comprised 23.1 percent of high-risk malignancies (p = 0.20). There was no significant difference in RET expression among cell variants (p = 1). CONCLUSION: The study of 101 papillary thyroid carcinomas at the King Chulalongkorn Memorial Hospital disclosed high frequency of RET expression (46.5%) and this is the only data among Thai patients that has ever been documented in the literature. Although, the gene expression in the tumor tends to be associated with good prognostic features but it was not distinct enough to be statistically significant.

Association between different variants of papillary thyroid carcinoma and risk-group according to AMES (age, metastasis, extent and size) classification system.

OBJECTIVE: To study the association between cell variants of papillary carcinoma and AMES (Age, Metastasis, Extent and Size) risk classification. MATERIAL AND METHOD: One hundred and twenty-one cases of papillary thyroid carcinomas were subclassified for cell type and risk-groups according to AMES classification system. Correlations between both variables are evaluated RESULTS: Among different cell variants of papillary carcinoma, solid cell pattern has the highest proportion of high-risk tumor classified by the AMES criteria, comprising 75% followed by tall cell subtype with 33.3% of high risk patients. Conventional papillary carcinoma has only 8.3% of high-risk group. Follicular and encapsulated variants as well as microcarcinoma (< 1 cm) are all categorized as low-risk neoplasms. CONCLUSION: The present study indicates that there is association between cell variants and AMES prognostic index. The authors, therefore, emphasize the importance of cell variants in predicting the prognosis of papillary carcinoma.