giant cell tumor ( gct ) of bone is a relatively common benign bone lesion . gcts are usually located in long bones , and most lesions are found around the knee . although gcts have been observed in other less frequent sites , such as the patella , great trochanter , and skull ; involvement of the olecranon we present a case of solitary gct of bone in the olecranon that was confirmed by preoperative needle biopsy and postoperative histological examination . therefore , the treatment included intralesional curettage , allogeneic bone grafting , and plating . at 26 months follow - up , the patient had no local recurrence . informed written consent was obtained from the patient for submission of the data for publication . an approval from the institutional review board a 32-year - old female was admitted to the first hospital of jilin university of changchun with a complaint of left elbow pain after a minor injury . upon physical examination , obvious tenderness was observed at her left olecranon , but no soft tissue mass was palpated . anteroposterior and lateral plain radiographs showed an expansile lytic lesion located in the left olecranon and extending into the subchondral region and the coronoid process . cortical breach was also identified in the dorsal aspect of the olecranon , suggesting a pathological fracture as a source of the pain . magnetic resonance imaging ( mri ) showed no soft tissue extension [ figure 2 ] , but the tumor had broken through the subchondral bone and extended into the elbow joint . anteroposterior and lateral plain radiographs showing an expansile lytic lesion located in the left olecranon and extending into the subchondral region and the coronoid process . note the pathological fracture in the dorsal aspect of the olecranon ( white arrow ) magnetic resonance imaging ( mri ) showing a relatively well - defined lesion of hyperintensive signals in a t2-weighted image , and no soft tissue extension the differential diagnosis included gct of bone , solitary bone cyst , metastasis , and brown tumor of hyperparathyroidism . a fine needle was positioned in the pathological fracture area along the operative incision after the administration of local anesthesia . a needle biopsy was then performed and a gct of bone was identified by pathological section . in order to prevent local recurrence , en bloc resection surgery was proposed , but the patient refused . thus , the patient was managed with intralesional curettage , allogeneic bone grafting , and plating . during the operation , gross findings of the tumor indicated that it was soft in texture and yellow in color . histology revealed that the tumor was composed of mononuclear ovoid and spindle - shaped cells associated with multinucleated giant cells and macrophages . this appearance was characteristic of gct of bone [ figure 3 ] . at the 26-month follow - up , the patient did not present with any local recurrence . histological analysis showing that the tumor was composed of mononuclear ovoid and spindle - shaped cells associated with multinucleated giant cells and macrophages . in addition , patients with gcts of bone present most often in the 3 or 4 decade of life . most gcts arise in metaphysical - epiphysical areas and are most commonly found in the distal femur , proximal tibia , and distal radius . other less frequent sites include the proximal femur , vertebral bodies , distal tibia , proximal fibula , hand , and wrist . in addition , gcts occurring in the patella and great trochanter have been reported . in several large studies , a total number of 1,447 gct of bone cases has been reported , but none of them were located in the olecranon . , reported one patient with multicentric gcts involving the left proximal ulna from a 12 year retrospective study conducted at the mayo clinic . to the best of our knowledge , the olecranon ossific nucleus first appears around 9 years of age and fuses completely by 12 - 15 years of age , which is relatively earlier than other long bones . the radiographic appearance of gct is usually characteristic of the disease and may be sufficient for making a correct diagnosis . however , in this case , although the plain films showed characteristic findings of gct , it was difficult to make a definitive conclusion . this was largely due to the rare location of the lesion , and the olecranon is a rare area for neoplasms to occur . only a few cases involving this anatomical region a brown tumor resulting from hyperparathyroidism also presents with similar radiographic features as this type of tumor . however , the clinical course and x - ray examination of this case excluded those differential diagnoses . other than the eccentric location , the lesion in this case had characteristics that were similar to lesions in bones with a smaller diameter , such as the proximal fibula . intralesional curettage has been the preferred treatment for most cases of gct of bone , despite a higher incidence of local recurrence . the use of local adjuvants , such as liquid nitrogen , bone cement , and hydrogen peroxide , may reduce the rate of local recurrence . radiotherapy has also been used to treat gct of bone in order to decrease local recurrence and is especially useful for treating difficult locations , such as the spine and sacrum . gct of bone is a relatively common benign bone lesion that is usually located in long bones , while involvement of the olecranon is extremely rare .
giant cell tumor ( gct ) of bone is a relatively common benign bone lesion and is usually located in long bones , but involvement of the olecranon is extremely rare . here , 
 we present a case of solitary gct of bone in the olecranon that was confirmed by preoperative needle biopsy and postoperative histological examination . 
 the treatment included intralesional curettage , allogeneic bone grafting , and plating . 
 at 26 months follow - up , the patient had no local recurrence .