Chondroblastoma of the Patella with Secondary Aneurysmal Bone Cyst, an Easily Misdiagnosed Bone Tumor: A Case Report with Literature Review

Abstract Background: Chondroblastoma (CB) is a rare, primary, benign bone tumor that common affects men aged 15-20 years. It is usually detected in the epiphysis of the long bones, such as the proximal femur, humerus, and tibia. However, CB is extremely rare in the patella, especially in combination with secondary aneurysmal bone cyst (ABC). In fact, this complicated condition can be easily confused with other common bone tumors of the patella. Case presentation: We have presented here the case of a 30-year-old man who was suffering from the anterior knee pain for the past 6 months that got aggravated since the past 2 weeks. Osteolytic bone destruction in the patella could be detected in both his X-ray and computed tomography (CT) examinations, while the magnetic resonance imaging (MRI) detected a fluid level. Accordingly, secondary ABC was presumed. We diagnosed the condition as giant cell tumor (GCT) with secondary ABC and accordingly performed curettage inside the focus region by autogenous bone grafting in accordance with the patient's medical history, physical manifestations, results of physical and ancillary examinations, and the disease characteristics. However, the in- and postsurgical outcomes indicated that the patient’s histopathology was consistent with that of typical CB, suggesting a definitive error in diagnosis. Accordingly, the patient was finally diagnosed with patella CB along with secondary ABC.Conclusions: Past studies have demonstrated that the 3 commonest bone tumors affecting the patella are GCT, CB, and ABC. We believe that the condition of patella GCT and CB accompanied with secondary ABC can be easily misdiagnosed. Performing incision biopsy or excision biopsy and conducting histological examination may be the most effective approach to identify and distinguish among these diseases.

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Chondroblastoma of the patella with secondary aneurysmal bone cyst, an easily misdiagnosed bone tumor:a case report with literature review

BMC Musculoskeletal Disorders ◽

10.1186/s12891-021-04262-0 ◽

2021 ◽

Vol 22 (1) ◽

Author(s):

Jianping Zheng ◽

Ningkui Niu ◽

Jiandang Shi ◽

Xu Zhang ◽

Xi Zhu ◽

...

Keyword(s):

Aneurysmal Bone Cyst ◽

Bone Tumors ◽

Bone Cyst ◽

Bone Destruction ◽

Autogenous Bone ◽

Excision Biopsy ◽

Secondary Aneurysmal Bone Cyst ◽

Magnetic Resonance Imaging Mri ◽

The Right ◽

Incision Biopsy

Abstract Background Chondroblastoma (CB) is a rare, primary, benign bone tumor that commonly affects men aged 15–20 years. It is usually detected in the epiphysis of the long bones, such as the proximal femur, humerus, and tibia. The patella is an infrequent site. CB with secondary aneurysmal bone cyst (ABC) is extremely rare in the patella, which can be easily confused with other common bone tumors of the patella. Thus, it is necessary to make the right diagnosis to get a good outcome. Case presentation We have presented here the case of a 30-year-old man who was suffering from anterior knee pain for the past 6 months that had aggravated 2 weeks before the presentation. Osteolytic bone destruction in the patella could be detected in both his X-ray and computed tomography (CT) examinations, while the magnetic resonance imaging (MRI) detected a fluid level. Accordingly, secondary ABC was presumed. We diagnosed the condition as giant cell tumor (GCT) with secondary ABC and, accordingly, performed curettage inside the focus region with autogenous bone grafting following the patient’s medical history, physical manifestations, results of physical and ancillary examinations, and the disease characteristics. However, the intraoperative and postoperative outcomes indicated that the patient’s histopathology was consistent with that of typical CB, suggesting a definitive error in diagnosis. Accordingly, the patient was finally diagnosed with patella CB along with secondary ABC. Conclusions Past studies have demonstrated that the 3 commonest bone tumors affecting the patella are GCT, CB, and ABC. CB with secondary ABC can be easily misdiagnosed as GCT with secondary ABC or ABC. Performing incision biopsy or excision biopsy and conducting histological examination may be the most effective method for suspected CB with secondary ABC.

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Chondroblastoma: An Update

Archives of Pathology & Laboratory Medicine ◽

10.5858/arpa.2016-0281-rs ◽

2017 ◽

Vol 141 (6) ◽

pp. 867-871 ◽

Cited By ~ 21

Author(s):

Wenqian Chen ◽

Lisa M. DiFrancesco

Keyword(s):

Aneurysmal Bone Cyst ◽

Bone Cyst ◽

Cyst Formation ◽

Giant Cells ◽

Lytic Lesion ◽

Primary Bone Tumor ◽

Hemosiderin Deposition ◽

Secondary Aneurysmal Bone Cyst ◽

Primary Bone ◽

Chondroblastic Osteosarcoma

Chondroblastoma is a rare primary bone tumor of young people that typically arises in the ends of the long bones. Radiologic investigations show a small, circumscribed, lytic lesion. The tumor is characterized histologically by the proliferation of chondroblasts along with areas of mature cartilage, giant cells, and occasionally, secondary aneurysmal bone cyst formation. Chondroblastoma, however, may also present with atypical features, such as prominent hemosiderin deposition, numerous giant cells, or the presence of a large aneurysmal bone cyst component. Malignant entities such as clear cell chondrosarcoma and chondroblastic osteosarcoma must also be considered. Recently, immunohistochemical stains such as DOG1 and SOX9 have been described in chondroblastoma, and K36M mutations in either the H3F3A or H3F3B genes have also been identified. While generally regarded as a benign entity, chondroblastoma manifests an intermediate type of behavior, given its ability to recur locally, and rarely, metastasize.

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