 Good afternoon everyone, today I'm going to be presenting my paper on incidents of secondary and neurosomal bonuses in cases of giant cell tumour. I'm Dr. Ruben Winston, I'm a GR3 from MGA Medical College in Mumbai, so coming to the introduction, giant cell tumour or GCT of the bone is an uncommon relation representing up to 9.5% of primary bone neoplasms and it is thought to originate from the undifferentiated cells of the supporting tissue of bone marrow. It is most commonly seen in early adulthood with peak incidents in the second to third decade with a slight female preponderance and usually seen in a skeletally matured patient with fused devices. The location of the GCT is the most important feature for the diagnosis since approximately up to 99% of the lesions are extant up to within 1 cm of the subcortical bone. The stroma of the GCT contain numerous thin walled vascular channels often with areas of hemorrhage and are presumed to be in association with secondary and neurosomal bonuses or ABC formation. Cystic components that indicate a secondary ABC may be reported in up to 14% of GCT. The aim of the study was to evaluate the incidence of secondary ABC in cases of a giant cell tumour. The objective was to evaluate the imaging findings of cases of GCT and check for any secondary ABC changes within them and compare it with the available literature. So the source of data for the study were cases of GCT around the knee joint including proximal tibia and distal femur and who had undergone an MRI at the Territory Care Centre in Kamate. A brief patient history was collected from the reference clinician and post-op follow-up was also done to confirm the diagnosis. The method was a retrospective study. It was done over a period of 6 months from January to June of 2021 on 10 patients who had painful swelling over the knee and MRI findings which were consistent with giant cell tumour. The MRI was done on a Toshiba 1.5 Tesla machine using surface coil for the knee. A sample size was 10 patients. Inclusion criteria, it inclusion was for all patients who had MRI findings of giant cell tumour. Only patients of giant cell tumour around the knee including proximal tibia and distal femur were included in the study. Other locations of GCTs were not included in the study. So after the study, after the retrospective study was done on 10 patients, it was found that out of the 10 patients, only two of the cases showed secondary changes of aneurysmal bond cyst formation within the GCT. Of the 10 cases included, 7 of them were females and 3 of them were males. Out of the 8 cases of GCT was in the proximal tibia while just two cases were in the distal femur. Both of the positive cases which had secondary ABC changes, the diagnosis was confirmed on histopathological correlation post the surgical excision. So this were the imaging findings. So the two positive cases X-rays have been included. So the first one, the X-ray A, APN lateral of around the knee joint, so there is a lytic expansile lesion in the proximal tibia extending up to the articular surface. It has shown multiple separations within it and no matrix is seen. The borders are pretty well defined, it is associated with cortical thickening. And yeah, so these findings were most likely the size of a giant cell tumor. And the second B, the BX-ray shows a similar, very similar lesion noted in the distal femur extending up to the articular surface with similar lytic expansile lesion. So MRI picture of the same cases. So this was the first one was a 19 year old female who had a mass lesion showing low signal on T1, multi-chambered high signal intensities on T2 weighted images. And a few of the chambers showed fluid fluid levels, the arrow is pointing to it which appeared to show blooming on susceptibility weighted imaging as well. On post-contrast study, the solid component of the mass lesion showed enhancement, well cystic component showed just peripheral enhancement and no central enhancement. It appeared to slightly involve the soft tissue on the posterior aspect with mild enhancement noted in the surrounding soft tissue as well. And incidentally, a CT was also done pre-op and in the soft tissue window, which is the second image on axial sections, we can see there is a fluid level noted with one part of the fluid showing hyper dense, hyper density on CT scan. So probably areas of hemorrhage and on the bony window in coronal images, it shows that there was in fact a cortical break, cortical thinning was present and cortical break was noted in the lateral aspect with soft tissue involvement being suspected on the MRI in the same location as well. So all put together, these findings were most likely suggestive of a GCT with a secondary ABC changes. And the other positive case in this study was a 60 year old male. He had similar come, he had similar findings in his distal femur, which showed multiple lytic cystic solid mass lesion in extending up to the articular surface with multiple separations within. There were areas of low T1 and T2 signal on, there were low signal areas on T1 and T2 weighted images in the mass lesion. And that area on susceptibility weighted or gradient images showed blooming. So that was suspected to be areas of hemorrhage or areas with permanent blood products and incidentally as the arrow points, they were very subtle but areas of fluid levels as well. So this was also the, I mean given diagnosed as case of GCT with secondary ABC changes. Both cases on HPE post excision, post surgical excision was confirmed, the diagnosis was confirmed to be GCT with a secondary ABC change. Coming to the discussion part, GCT is a primary bone tumor that occupies predominately in the meta epifysial region of long bones. It is seen in mature skeleton in young adults with 80% of the cases seen in ages 20, between 20 to 40 years. And more nearly all of them occurring in tubular long bones. So 50% of the GCT is seen in distal femur and proximal tibia. And it may be seen in other locations as well with the less common sites being flat bones like ribs in skull, patella, sternum and clavicle as well. On X-ray, there is a characteristic purely lytic lesion with destruction seen extending to the end of the subarticular surface with mineralization is being absent. And it is a lytic lesion. The center of most radial center is mostly a dilution with increasing density towards the periphery. These tumors are usually within the bone and they may present with cortical thinning and causing cortical thinning giving a characteristic axial thinning of the cortex or it could also be a bit more aggressive and extend a bit destroy the cortex and extend into the soft tissue surrounding surrounding soft tissue as we saw in one of the cases. On MRI, it is MRI is the best imaging modality as of now for imaging because of its superior contrast resolution and multiple and our imaging capabilities. And it is useful in differentiating the extra urges extent and the articular surface involvement. However, when we when we want to look at the cortical destruction and if it is extending beyond the cortex CT is still superior to MRI. So on an MRI we can see low grade low intensity and heterogeneously hyper intensity on T2 weighted images. And the solid part of the lesion is slightly contains sinusoidal vessels which predisposes to hemorrhage and they may have extensive hemocytic deposition within the tumor as due to this reason and may show low low intense low signal intensity on T1 and T2 weighted images and they may show blooming on gradient images. Now the ABC component in GCT is not relatively less common as come in as in given in the literature it is seen in up to 14% of the cases and case of GCT with prominent ABC element may have a slightly more aggressive appearance on radiograph reflecting the expand cell cystic component. Now cystic areas are typically well seen on CT and MR imaging with ABC showing multiple fluid fluid levels in both modalities. The lesion containing proximal sorry prominent ABC component the solid region the solid part of the GCT often lobular areas found predominantly in the periphery mostly towards the periphery of the neoplasm while cystic areas towards the center and also the cystic areas enhanced with the thin and delicate peripheral and septate pattern. So there is peripheral enhancement and on contrast study the solid and solid part of the GCT appears to enhance diffusely reflecting the hyper vascular tissue which is already confirmed by in the pathological pathological analysis while the diagnosis of a secondary ABC does not exactly change the course of action for this treatment which is excision surgical excision of the tumor biopsy in it is important in cases of in the diagnostic part of this tumor since the biopsy taken from the cystic area may result in a wrong diagnosis. So care has to be taken to be mentioned in the report of in case there is a secondary ABC. So in conclusion it is noted that cases of giant cell tumor in case of giant cell tumor there is a slight predilection for the development of a secondary ABC within them with an incidence of about 40 to 14 to 20% as seen in the study therefore a careful review of the imaging findings must be done to exclude the potential of an ABC that may be secondary to an underlying tumor. Thank you. And these are my references. These are the five references I had used.