# Introduction iant cell tumor (GCT) is a tumor found most often in the ends of long bones and is essentially located in the epiphyseal or metaphyseal or epiphyseal equivalent portions of bone. It is a locally aggressive neoplasm, generally arising in adults between the ages of 20 and 40 years, clinically possessing metastatic potential. 2 The classic location is around the knee joint and it starts in the epiphysis spreading to the metaphysis and may erode the cortex in 25% of the cases. Approximately 10% of these tumors have a malignant course. 3 The patella is a rare site with a reported incidence of less than onepercent. Rare multicentric forms have been reported. 4 Author ?: Staff of Department of Orthopaedic and Traumatology, Faculty of Medicine Brawijaya University/ Saiful Anwar Hospital, Malang, Indonesia. e-mail: aditflea@gmail.com Author ?: Resident of Department of Orthopaedic and Traumatology, Faculty of Medicine Brawijaya University/ Saiful Anwar Hospital, Malang, Indonesia. In this article, we report a case of GCT originating from the left patella which was diagnosed on fine needle aspiration cytology, magnetic resonance imaging and already performed excision, curettage, and bone cement. # II. # Case Report A 14-year-old female from Malang, East Java, presented with a one year history of a progressively growing mass in the left patella associated with slight pain that has aggravated with activity for 6 months. It measured 42 cm in its largest diameters. The overlying skin was normal. She had no pulmonary and other systemic symptoms. All hematological and biochemical investigations were within normal limits. Patient underwent plain X-ray left knee AP and lateral views. Radiograph reveal expensile lytic lesion in left patella with marked thinning of cortex in anteroinferior aspect with few sclerotic septa within. (FIG. 1) At the end of November, curettage of the lesion and bone substitution were performed with general anesthesia. These procedures were performed through an approximately 10 cm longitudinal incision directly above the area. The periosteum was detached from the surface of the patella with a raspatory to make an oval incision. The main part of the tumor was solid and yellow-brown with partial retention of blood (Fig. 5). Macroscopically, it appeared to be a giant cell tumor. We carefully removed the contents with a curette, filled the defect with approximately 5g of calcium hydroxyapatite ceramic and fixed it with two screws and closed the incision in a routine manner. X-ray left knee AP and lateral views post surgery were taken to confirm whether the defect was filled with bone substitution component (FIG. 6). Fig. 5: Macroscopically of the tumours, solid and yellow-brown with partial retention of blood Fig. 6: Post surgery X-ray AP and lateral of left knee Hystopathological examination was performed after the surgery, and showed multi-nucleated giant cell with more than 20 nucleus, short spindle shaped cells, bone tissues, and calcification. No cellular atypia and few mitotic figures were observed. On the basis of these findings, the lesion was diagnosed AS a giant-cell tumor rather than as an aneurysmal bone cyst (FIG. 7). ImmunohystochemicalWAS performed to confirm the diagnosis and found positive result in CD68 staining (FIG. 8). The diagnosis was confirmed to be giant-cell tumor of left patella. The affected part was immobilized with a splint for approximately 2 weeks after the operation. Weight bearing and range of motion exercises were initiated after the suture was removed. Full weight bearing was allowed by approximately 4 weeks. At present, 6 months after the operation, the patient has no arthralgia and full range of motion for the knee. # III. # Discussion Bone tumors arising in the patella are comparatively rare. According to a survey by the Bone and Soft Tissue Tumor Committee of the Japanese Orthopedic Association, of the 27, 403 primary bone tumor cases were reported for 32 years from 1972 to 2003 in which tumors involved the lower extremities in 70.5% or 13,860 of these cases. 1 However, tumors arising in the patella were encountered in only 75 cases, accounting for 0.5%of all cases. Of these 75, 4 were osteosarcomas, i.e., malignant bone tumors, and 71 were benign bone tumors. The benign tumors included chondroblastoma (n?24), giant cell tumor (n?22), and solitary exostosis (n?14).Less than 50 cases of giant cell tumor of the patella have been reported in the international literature in the developed world. Clinically, the patients with the patellar GCTs usually complained about knee pains and/or swelling. [3][4][5][6][7] Physical examination may show redness, local heat, swelling, effusion, tenderness, lump, crepitus, and the decrease of motional range. [3][4][5][6][7] The laboratory findings on some severe patients showed an increase of serum alkaline phosphatase (AP) and erythrocyte sediment rate (ESR). 8 Radiographs revealed an osteolytic lesion of the patella with destruction of the bone, and sometimes, soap bubble appearance. 3 Magnetic resonance imaging (MRI) showed abnormal extension and lesion of the patella, and there may be some evidence of adjacent tissues and sclerotin. 8 Additionally, chest radiography and bone scintigraphy are necessary for GCT patients to determinate the possible metastasis on the lung and other bones. A needle biopsy or incisional biopsy of the patella is recommended for the diagnosis. The histopathological features of the patellar GCT, which mainly include numerous giant cells, short spindleshaped cells, bone tissue calcification, and a few mitotic should be distinguished from aneurysmal bone cyst or chondroblastoma. The histological examination of the aggressive GCT showed a compact stroma with nuclear atypia, frequent mitotic figures, hyperchromatism, and the unevenly distributed giant cells. 7 Curettage with a combination of cryosurgery may be attempted in early stage of the disease but it still carries the risk of recurrence about 25 to 40%. 10 For small, benign GCT (Enneking stage 2), intralesional curettage orpartial patellectomy with filling of the bone void and reconstruction of the extensor mechanism is the first choice in treating GCT of the patella. But if the patellar GCT is extensive or malignant (Enneking stage 2 to 3), patellectomy combined with adjuvant treatment and resection of metastasis is recommended. 8 Resection may be the only form of treatment left in advanced cases which offers good to excellent functional results. 2 Follow up in such cases have shown a long term good function and no recurrence with patellar resection, thus emphasizing the role of patellectomy in such advanced case. 2 Future reconstruction procedures using osteoarticular grafts after resection in such advanced cases may be a feasible option. 10 IV. # Conclusion This case illustrates the fact that giant cell tumors of patella can be mistaken for ABC and other malignant tumors of bone and soft tissues. Fine needle or biopsy would be diagnostic if adequate specimen is obtained and can also confirmed with immunohysto chemical staining. Surgery is the primary mode of treatment for this case. Curettage accompanied with bone substitution and cryosurgery may be attempted in early stage and patellectomy for advance stage. For future reconstruction procedure osteo-articular grafts can be used after resection that may be feasible option for advance cases. 1![Fig. 1: Antero-posterior and lateral radiograph showing expensile lytic lesion in left patella Patient underwent MRI of left knee. T1 and T2 weighted images were obtained in axial and sagittal 3x2x2 cm heterogeneous lobulated expensile soft tissue mass in right patella extending up to the articular surface, and a fluid-fluid level was observed. The possible differential diagnosis from MRI include giant cell tumor or aneurysmal bone cyst. Luckily the articular cartilage at posterosuperior part is still intact.](image-2.png "Fig. 1 :") 2![Fig. 2: Axial T1 and T2 MRI show defect in anteroinferior aspect of patella](image-3.png "Fig. 2 :") 34![Fig. 3: Sagital T1 and T2 MRI show fluid-fluid level To confirm the diagnosis, fine needle aspiration was performed at the anteroinferior aspect of patella. Hystopatological finding still cannot differentiate whether this isgiant-cell tumor or aneurysmal bone cyst although multi-nucleated giant cell was already found (FIG.4)](image-4.png "Fig. 3 :Fig. 4 :") 78![Fig. 7: Hystopathological examination shows multi-nucleated giant cell with more than 20 nucleus, short spindle shaped cells, bone tissues, and calcification](image-5.png "Fig. 7 :Fig. 8 :") 2![](image-6.png "2") © 2018 Global JournalsGiant-Cell Tumor of the Patella: Case Report * JOA Musculoskeletal tumor committee: Bone tumor registry in Japan 2008 Tokyo National Cancer Center * SPaudel PKayastha PPokhrel AShah RKGhimire MAAnsari Giant Cell Tumor of Patella: Journal of Institute of Medicine 2012 * EHutagalung Neoplasma Tulang Diagnosis danTerapi 2005 * Giant-cell tumor of the patella YYoshida TKojima MTaniguchi SOsaka YTokuhashi Acta Med Okayama 66 73 2012 * Iatrogenic seeding of a giant cell tumor of the patella to the proximal tibia OOfluoglu RDonthineni ClinOrthopRelat Res 465 260 2007 * Giant cell tumor of the patella and its management using a patella, patellar tendon, and tibial tubercle allograft RMalhotra LSharma VKumar ARNataraj Knee Surg Sports Traumatol Arthrosc 18 167 2010 * Late presentation of G.C.T. of the patella GChakraverty UChakraverty Internet J Orthopedic. Surgery 12 1 2009 * Primary Tumors of the Patella MSong ZZhang YWu MaKLu M Song et al. World Journal of Surgical Oncology 2015 * Pathology and Genetics of Tumours of Soft Tissue and Bone DChristopher 2002 * Sometimes malignant tumours of bone, in Camphell's operative orthopaedics PGCarneaale 1987 th ed. St. Louia, Moaby