case_images: PMC10858809_01
case_images: Frontal (A) and lateral (B) left knee radiographs show a well-defined proximal tibial lytic lesion with a sclerotic narrow zone margin centered in the proximal metaphysis. The left knee MRI coronal STIR (C) and sagittal T1 fat-saturated post-contrast image (D) show a well-defined proximal tibial lesion with central T2 hyperintensity and a thin rim of T2 sclerotic hypointensity. There is extensive edema in the surrounding bone marrow and soft tissues. Histopathological assessment (E and F) shows infiltration by round or polyhedral chondroblasts with abundant eosinophilic cytoplasm and well-defined cell borders. The nuclei are oval, hyperlobulated with grooves. Pericellular lace-like or chicken wire-type calcification among degenerative chondroblasts can be seen focally. There is also a chondroid matrix and scattered osteoclast-type giant cells. Postoperative radiographs (G) show the tumor cavity curetted and filled with bone graft substitute.. STIR: Short TI inversion recovery.
case_images: cureus-0016-00000052129-i01.jpg
case_images: PMC10858809_01_cureus-0016-00000052129-i01.jpg
case_images: FIG1
case_images: Tumor samples were sent for the pathology, which showed typical changes of chondroblastoma (Figure 1, Panels E and F).
case_images: Surgical procedure. (A) Marking of the tibial tuberosity and skin incision. (B) K-wire was inserted and verified on AP and lateral views. (C) K-wire on the lateral radiographs with graduated ACL reamer. (D) Tumor as visualized by the endoscope, with brownish tumor tissue in the cavity. (E) Tumor cavity after curettage using curettes and irrigation; subchondral cartilage is seen on the cavity's roof. (F) Skin incision after closure.. AP: Anteroposterior.
case_images: cureus-0016-00000052129-i02.jpg
case_images: PMC10858809_01_cureus-0016-00000052129-i02.jpg
case_images: FIG2
case_images: A). A 2 mm K-wire was introduced into the lesion starting from the medial proximal tibia and directed to the lesion in the anteroposterior (AP) and lateral positions (Figure 2, Panel B). We then used the anterior cruciate ligament (ACL) reamers gradually up to size 10 mm to the sclerotic wall of the lesion to gain sufficient access and tunnel size to introduce the endoscope and the curettes (Figure 2, Panel C). A 30-degree angle endoscope was introduced to visualize the lesion, and variable angle micro-discectomy curettes were used to curette the lesion grossly under adequate visualization by the endoscope (Figure 2, Panel D). We have also ensured that the overlying cartilage was not penetrated, and the entire tumor was curetted up to bleeding cancellous bone (Figure 2, Panel E). The wound was closed in layers, and the skin was closed by subcuticular sutures (Figure 2, Panel F).