Osteochondroma is the most common bone tumor representing 20%–50% of all benign bone tumors and 10%–15% of all bone tumors. Osteochondroma has similar radiological appearance in both solitary and multiple forms; the latter is an autosomal dominant disorder termed hereditary multiple exostoses. Associated complications of osteochondroma include deformity, fracture, neurovascular compromise, bursa formation, and malignant transformation. Measurement of the cartilage cap thickness is an important index suggesting secondary malignancy of osteochondroma. The upper limit of cap thickness after skeletal maturation is 1.5 cm which can be reliably measured on ultrasound or magnetic resonance imaging. Hereditary multiple exostoses are linked to the mutations of different exostoses genes located on chromosome 8, 11, and 19. We reported cases of two siblings presented with multiple osteochondromas managed by surgical excision. We evaluated their clinical and radiological presentation, genetic correlations and compared with the literature.

The coexistence of multiple synchronous primary malignancies is uncommon. The coexistence of hepatocellular carcinoma (HCC) and renal cell carcinoma (RCC) is even rarer. We present a case of a 44-year-old male patient with a history of chronic hepatitis B and a right renal mass treated by radical nephrectomy. At the 2-month follow-up, a new lesion was detected in the left lobe of the liver. Postsurgery histologic evaluation with immunohistochemical study of both lesions confirmed the renal and hepatic lesions to be RCC and HCC, respectively.

Background: To determine the molecular subtypes and correlation between molecular subtypes and histopathological features in breast cancer in Vietnam and Italy. Material and method: 88 patients with invasive breast carcinoma (BC) in both Hue Central Hospital and Hue University Hospital in Vietnam during 1 year from April 2016 to April 2017 as well as 235 patients from the same category of women in Sassari University Hospital, Italy during the year 2016 were collected. All patients were examined for immunohistochemistry (IHC) with four markers ER, PR, HER2, and Ki67. The immunofluorescence in situ hybridization (FISH) test was applied for cases with HER2 (2+)/ IHC. Results: Breast cancer in Vietnam had the highest Luminal B (LB) rate, at 37.5%, followed by HER2 enrich (22.7%) and triple-negative breast cancer accounting for 21.6%. Luminal A (LA) accountd for the lowest proportion (18.2%). In contrast, breast cancer in Italy has the highest rate of Luminal A (54%), LB accounted for 34.5%, triple-negative occupied 10.6% and HER2 enrichment has a very low rate (0.9%). There was a statistically significant correlation between molecular subtypes and pathological features such as histologic grade, axillary lymph node, and stage of disease in both Vietnamese and Italian groups (p<0.005). Most breast cancers in Vietnam and Italy belong to the Luminal A with low histologic grade, early-stage disease, and no metastasis. No statistically significant association was found between molecular subtypes and tumor size in the Vietnamese breast cancer group. By contrast, this association was statistically significant with p<0.05 in Italy. Conclusion: There is a significant difference in the molecular subtypes and the correlation between molecular subtypes and histopathological features between Vietnamese and Italian breast cancers. The two more common subtypes in Vietnam are LB and HER2, while in Italy they are LA and LB. The rate of HER2 subtypes in Vietnam is much higher than in Italy Key words: Invasive breast carcinoma, molecular subtype, Vietnam, Italy

Background: The gastrointestinal tract is the most common site of extranodal Non-Hodgkin lymphoma, accounting for 20% to 40% of all extranodal lymphomas. This study aims to accomplish the objective: classify the prevalent histopathological patterns of gastrointestinal lymphoma according to WHO 2019 classification based on histopathology and immunohistochemistry. Subjects and methods: A cross-sectional study sampled on 76 gastrointestinal lymphoma patients to be examined and treated at The Hue University of Medicine and Pharmacy Hospital and Viet Nam National Cancer Hospital from January 2021 to June 2022. Results: B cell and T cell Lymphoma made up 97.4% and 2.6%, respectively; among them, the most common pattern was diffuse large B-cell lymphoma (59.2%,), Mucosa-associated lymphoid tissue lymphoma (17.1%), Mantle cell lymphoma (15.8%), Follicular lymphoma (2.6%), High-grade B-cell lymphoma (1.3%), and Small lymphocytic lymphoma (1.3%). The most frequent position was the stomach (60.5%), the rectum and colon, small intestine, and ileocecal region at 19.7%, 10.5%, and 9.3%, respectively. Conclusions: Using histopathology and immunohistochemistry can classify the majority of gastrointestinal Non - Hodgkin lymphoma according to the WHO 2019 classification. Immunohistochemistry plays an important role in the classification of gastrointestinal lymphomas. Key words: gastrointestinal lymphoma, WHO 2019 classification, immunohistochemistry

Introduction: Cancer is malignant disease, one of the leading cause of deadth at the global level. The determination of origin of tumors is really essential for not only prognosis but also effective treatment orientation for cancerous patients. Objective: Defining histopathological types of malignant epithelial tumors and determining the origin of tumors by CK7, CK20 and other immunohistochemical markers. Patients and methods: A cross-sectional study of 50 patients diagnosed carcinoma and CK7, CK20 and other immunohistochemical markers stain at Hue University of Medicine and Pharmacy Hospital from January, 2020 to December, 2020. Results: The results of histopathological types: lymph node metastatic carcinoma took up the highest percentage (30%), followed by lung cancer, hepatocellular cell carcinoma, gastric cancer and other organs with 28%, 18%, 10% and 2% respectively. The value of expression of CK7, CK20 and other immunohistochemical markers in differentiated diagnosis of the origin of tumors: CK7, CK20 positive 46%, 12% respectively. The combination of expression of CK7 and CK20: the co-expression of CK7 and CK20 with positive and negative was 2%, 44% respectively; the expression of CK7 positive and CK20 negative and vice versa was 44% and 10% respectively. CKAE1/3 with TTF1 (11/19), P63 (7/14), CEA (6/6), Ki-67 (13/2) and CK19 (10/6) had high positive percentage. Conclusion: Lymph node metastatic carcinoma was one of the most popular histopathological type. There was a statistically significant relationship between the expression of CK7 and CK20. The use of CK7, CK20 and other immunohistochemical markers can assist pathologists in determining exactly the origin of malignant tumors. Key words: carcinoma, CK7/CK20, histopathology, immunohistochemistry, metastasis.