 Hello everyone. This is Dr. Sugiyani Mahapatra, a secondary PG resident from SCV Medical College and Hospital Kotak, presenting a paper in city bus 2023. I am presenting a rare case, interesting case. The case was my, the topic name is Multifocal Aven Sarcoma, clinically misdiagnosed as transverse myelitis, a pictorial review with city. To start with, we all know that Aven Sarcoma is the second most common childhood primary bone tumor after osteosarcoma. But here we have a rare case where we have Aven Sarcoma affecting multiple bones, having soft tissue expansion and a large posterior mediasional mass arising from the parapartibral region. So to start with the, with some brief clinical history, we have 10 year old child presented with complaints of inability to whack for two months, inability to move the both legs for one month, fever on and off for one month. Child was apparently well two months back to start with the developed weakness of the both lower limbs, gradually started inability to whack and unable to move both legs. Occasional fever was there, child was admitted to the pediatrics department of our college and treatment was started with a provisional clinical diagnosis of transverse myelitis. On routine chest X-ray PA view, they found a rounded opacity and the child was referred to us for CCT thorax evaluation. In CCT thorax evaluation, we found a soft tissue dense heterogeneously enhancing mass lesion in the posterior mediasinum in the right parapartibral region with internal coarse calciplication and a ill-defined heterogeneously enhancing soft tissue dense lesion in the left scapula with adjacent bony lytic lesions with periastial, speculated periastial reaction. These are the images, this is the scapula region of the left scapula and this is the huge posterior mediasinum mass arising from the parapartibral space. This is the same image. In CCT thorax examination, these parapartibral soft tissue lesions prompted us to go for abdomen CCT, abdomen pelvis examination because we thought of more of these lesions in abdomen and pelvis. So, we proceed for CCT abdomen pelvis examination of the same patient. And in CCT abdomen contrast enhanced abdomen pelvis examination, we found similar characteristics, similar morphology lesions that is soft tissue dense lesions with speculated thick periastial reactions like sunburst appearance in right iliac bone. Similar lesion also we found in the right femur just below the greater trochanter. This is the lesion. And also we found some parapartibral lesions in the lower vertebrae with which possibly encasing the both ureters causing right moderate and left mild hydrourator nephrosis. Also we found similar lesions in the pre sacral region with multiple lytic lesions in the vertebral body. So, by looking all these lesions in the CET images, we thought of a professional diagnosis radiologically as multifocal in sarcoma and we plan for biopsy from multiple sites. Then samples are taken from the scapular lesion, from the medicinal lesion and the right iliac bone lesion. And biopsy report confirmed it to be a case of aving sarcoma. And also we performed a CD marker like CD99 which also found to be positive. So, these are few images we have taken from our pathology department of the same patient which showing the small blue round cells and this image showing the CD99 positivity. So, our case has been proved to be a case of multifocal aving sarcoma proven in biopsy also. So, to discuss few points about aving sarcoma, it is the second most common primary bone tumor of the childhood after osteosarcoma, but in our case it is somewhat interesting because it has involved multiple bones with multiple soft tissue expansion. It mainly presents as destructive mothetane permeate evolution lesions with soft tissue expansion in the shaft of long bones with onion skin type of periostial reactions. Age group commonly involved 10 to 20 years, male-female ratio is 1.5 is to 1, slightly male males are more affected. In our case it is also a tenured male child. So, age is fitting and also sex is fitting. Location wise lower limb tumor is the most common site. There will be bones in 20% cases, upper limb 13% cases, spine and ribs also in 13% cases, skull and face in 2% cases. In our case it involved the femur, right femur, the right iliac bone, lept scapula and multiple vertebrae with para-vertebral soft tissue components. Clinical future wise when it involves a single lesion or single bone, mainly localized pain and swelling will be there, fever will be there and elevated ESR will be there, ESR or CR will be there. Imagining wise it is a meta-difficial or difficial tumor, central or medullary in origin, permeative destructive lesion with a wide zone of transition, soft tissue extension will be there. Hair on end or speculated periostial reaction is a specific feature of this tumor. Multilamilar onion skin peritoneal periostial reaction may be seen and codmen strangle is also seen in 25-27% of cases. These lesions will be seen both in X-rays and CT but CT will depict all these lesions in a better manner and in case of marrow involvement we will we can proceed for MRI. So to go with differential diagnosis we can take osteo sarcoma as a differential diagnosis then osteomyelitis, langerin cell osteocytosis, stress fractures and neuroblastoma if it is a case of less than five years of age. Then we can I can show the images of this in the study I can show. So this is the this is the study this is the this is the CCT abdomen CCT thorax study this is the midiastinal posterior midiastinal lesion possibly arising from the parapartibral soft tissue of the lesion. Here these are the soft tissue lesion of the scapula left scapula and this is CCT abdomen pelvis study. Here we can see the hair on end appearance or sunburst appearance, speculated periastial reaction in the right iliac bone. Also these lesions we can see in the femur also here right femur just below greater trochanter. We are also in the pre sacral region.