case_images: PMC9958242_01
case_images: Maximum abduction possible at the index visit
case_images: cureus-0015-00000034217-i01.jpg
case_images: PMC9958242_01_cureus-0015-00000034217-i01.jpg
case_images: FIG1
case_images: Restricted abduction up to 80  and flexion up to 70  on examination were noted at the index visit (Figure 1). The skin over the swelling was mobile and not fixed to the underlying tissues, with no sinuses, dilated veins, or scars (Figure 1).
case_images: Maximum possible abduction on the second visit with an increase in the size of the swelling
case_images: cureus-0015-00000034217-i02.jpg
case_images: PMC9958242_01_cureus-0015-00000034217-i02.jpg
case_images: FIG2
case_images: A plain radiograph at the index visit
case_images: cureus-0015-00000034217-i03.jpg
case_images: PMC9958242_01_cureus-0015-00000034217-i03.jpg
case_images: FIG3
case_images: Multiple septa were seen traversing the lesion, and a characteristic soap bubble appearance was noted (Figure 3).
case_images: A plain radiograph on the second visit showed an increase in the size of the lesion
case_images: cureus-0015-00000034217-i04.jpg
case_images: PMC9958242_01_cureus-0015-00000034217-i04.jpg
case_images: FIG4
case_images: On subsequent presentation, a repeat radiographic study showed a notable enlargement in the size of the lesion as compared to that of the index visit, along with a pathological fracture that was also seen during the index visit at the diaphyseal end of the tumor (Figure 4).
case_images: An MRI showed multiple cortical breaches and soft tissue extension; the articular surface was breached with tumor tissue eroding the articular cartilage. A: coronal image; B: axial image.
case_images: cureus-0015-00000034217-i05.jpg
case_images: PMC9958242_01_cureus-0015-00000034217-i05.jpg
case_images: FIG5
case_images: Histopathology examination . Large multinucleated osteoclast-like cells (yellow arrow)
case_images: cureus-0015-00000034217-i06.jpg
case_images: PMC9958242_01_cureus-0015-00000034217-i06.jpg
case_images: FIG6
case_images: A core biopsy was performed for a histopathological diagnosis, and a giant cell tumor was confirmed (Figure 6).
case_images: Preoperative templating for customizing the megaprosthesis
case_images: cureus-0015-00000034217-i07.jpg
case_images: PMC9958242_01_cureus-0015-00000034217-i07.jpg
case_images: FIG7
case_images: Preoperative planning was carried out, and templating for customizing the megaprosthesis was done (Figure 7).
case_images: Postoperative X-ray with the customized prosthesis in situ
case_images: cureus-0015-00000034217-i08.jpg
case_images: PMC9958242_01_cureus-0015-00000034217-i08.jpg
case_images: FIG8
case_images: Reconstruction was performed by using the customized megaprosthesis with a cemented stem (Figure 8), and rotator cuff muscles were passed through the slot designed in the proximal part of the prosthesis and reflected and sutured on themselves.