Immunohistochemical Evaluation of Myxoid Sarcomas- A Tertiary Care Hospital Experience

Abstract

Introduction: Myxoid sarcomas are a rare and heterogeneous group of tumours exhibiting overlapping histomorphological features with varied biological behaviour. Hence, additional ancillary techniques like Immunohistochemistry (IHC) are necessary for definite diagnosis and categorisation of the myxoid sarcomas. Aim: To identify the distribution of myxoid sarcomas among patients and also to evaluate the utility of basic IHC in the diagnosis of myxoid sarcomas. Materials and Methods: This was six years retrospective observational cross-sectional study carried out in the Department of Pathology, Madras Medical College and Rajiv Gandhi Government General Hospital, Chennai, Tamil Nadu, India, during the period of January 2008 - December 2013. Relevant pathological data of all the myxoid sarcomas reported during the study period were retrieved from the medical records. Corresponding Haematoxylin and Eosin (H&E) stained slides were reviewed and IHC was done using a panel of markers for confirmation. Results: Among the 57 myxoid sarcomas, 46% occurred in the age group of 41-60 years with a striking male preponderance (74%). Myxofibrosarcoma was the most common histological type (33.33%). All cases of myxofibrosarcoma were positive for vimentin while two cases showed focal Smooth Muscle Actin (SMA) positivity and one case showed focal CD34 positivity. Low grade fibromyxoid sarcomas were positive for only vimentin. Myxoid liposarcomas and extra-skeletal myxoid chondrosarcomas showed vimentin and S100 positivity. Myxoid Dermato Fibrosarcoma Protuberans (DFSP) was positive for vimentin and CD34 while synovial sarcoma with myxoid change was positive for vimentin and Pancytokeratin (Pan CK). Myxoid Malignant Peripheral Nerve Sheath Tumour (MPNST) showed 100% vimentin and S100 positivity while CD34 was positive in 12.5% of cases. Leiomyosarcoma with myxoid change was positive for vimentin, SMA, desmin and Pan CK. Conclusion: IHC is a valuable adjunct to light microscopy for the diagnosis of myxoid sarcomas.