Sasidharan, Siny VellukaraKumar, VinuPai, Radha RVasudevan, Sheela2015-11-102015-11-102014-10Sasidharan Siny Vellukara, Kumar Vinu, Pai Radha R, Vasudevan Sheela. A clinicopathological and immunohistochemical study of malignant peripheral nerve sheath tumors. International Journal of Research in Medical Sciences. 2014 Oct-Dec; 2(4): 1307-1312.2320-60712320-6012http://imsear.searo.who.int/handle/123456789/165433Background: Malignant Peripheral Nerve Sheath Tumor (MPNST) is a rare aggressive sarcoma that develops within a peripheral nerve and forms a diagnostic challenge in view of its varied histomorphology. This short series highlights the clinicopathological spectrum of 11 cases of MPNST and the incidence of neurofibromatosis 1 (NF1) association. Methods: This retrospective and descriptive study on MPNST was done in the department of pathology, Kasturba medical college Mangalore (Manipal University), India over a period of three years from January 2008 to December 2010. Cases which were histopathologically diagnosed as MPNST were reviewed & immunostains was done where ever indicated to rule out the differentials. Results: A total of 11 cases of MPNST were documented with a wide age range of 17-85 years. Male:female ratio was 2.6:1. Extremities (63.64%) were found to be the most common site. Location wise most of the tumors were deep seated (63.64%) and maximum cases were high grade (54.55%). NF1 association was seen in 2 cases. Heterologous elements in the form of chondroid differentiation was seen in one case. Immunostain with S-100 was focally positive in all the cases. Conclusion: MPNST is a highly aggressive sarcoma with poor prognosis characterized by a challenge in its diagnosis as it has several mimics. Its diagnosis necessitates the incorporation of clinicopathological features and IHC with S-100 protein.enMalignant peripheral nerve sheath tumorNeurofibromatosis (NF-1),Heterologous differentiationArticle