Background: The diagnosis of osteosarcoma (OSA) depends on clinicopathological and radiological correlation. A biopsy is considered the gold standard for OSA diagnosis. However, since OSA is a great histological mimicker, diagnostic challenges exist. Immunohistochemistry (IHC) can serve as an adjunct for the histological diagnosis of OSA. Special AT-rich sequence-binding protein 2 (SATB2) was recently described as a reliable adjunct immunohistochemical marker for the diagnosis of OSA. Methods: We investigated the IHC expression of SATB2 in 95 OSA and 100 non-osteogenic bone and soft tissue tumors using a monoclonal antibody (clone EPNCIR30A). The diagnostic utility of SATB2 and correlation with clinicopathological parameters were analyzed. Results: SATB2 IHC was positive in 88 out of 95 cases (92.6%) of OSA and 50 out of 100 cases (50.0%) of primary non-osteogenic bone and soft tissue tumors. Of the 59 bone tumors, 37 cases (62.7%) were positive for SATB2, and of the 41 soft tissue tumors, 13 cases (31.7%) were positive for SATB2. The sensitivity of SATB2 as a diagnostic test was 92.6%, specificity 50%, positive predictive value 63.8%, and negative predictive value 87.7%. Conclusions Although SATB2 is a useful diagnostic marker for OSA, other clinical, histological and immunohistochemical features should be considered for the interpretation of SATB2.

BACKGROUND: Inflammatory myofibroblastic tumor is a histopathologically distinctive neoplasm of children and young adults. According to World Health Organization (WHO) classification, inflammatory myofibroblastic tumor is an intermediate-grade tumor, with potential for recurrence and rare metastasis. There are no definite histopathologic, molecular, or cytogenetic features to predict malignant transformation, recurrence, or metastasis. METHODS: A 5-year retrospective study of histopathologically diagnosed inflammatory myofibroblastic tumors of various anatomic sites was conducted to correlate anaplastic lymphoma kinase-1 (ALK-1) expression with histological atypia, multicentric origin of tumor, recurrence, and metastasis. Clinical details of all the cases were noted from the clinical work station. Immunohistochemical stains for ALK-1 and other antibodies were performed. Statistical analysis was done using Fisher exact test. RESULTS: A total of 18 cases of inflammatory myofibroblastic tumors were found during the study period, of which 14 were classical. The female-male ratio was 1:1 and the mean age was 23.8 years. Histologically atypical (four cases) and multifocal tumors (three cases, multicentric in origin) were noted. Recurrence was noted in 30% of ALK-1 positive and 37.5% of ALK-1 negative cases, whereas metastasis to the lung, liver, and pelvic bone was noted in the ALK-1 positive group only. CONCLUSIONS: Overall, ALK-1 protein was expressed in 55.6% of inflammatory myofibroblastic tumors. There was no statistically significant correlation between ALK-1 expression, tumor type, recurrence and metastasis. However, ALK-1 immunohistochemistry is a useful diagnostic aid in the appropriate clinical and histomorphologic context.
Antibodies ; Child ; Classification ; Coloring Agents ; Cytogenetics ; Humans ; Immunohistochemistry ; Liver ; Lung ; Lymphoma ; Myofibroblasts* ; Neoplasm Metastasis ; Pelvic Bones ; Recurrence ; Retrospective Studies ; Tertiary Care Centers* ; Tertiary Healthcare* ; World Health Organization ; Young Adult