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 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.

Recurrent chondroblastoma of the talus: A case report and literature review of recurrent lesions in the foot and ankle

“…Non-specific, long-term symptoms often delay the diagnosis of these lesions [4] . Furthermore, chondroblastoma, giant cell tumours and ABCs share similar clinical and radiological findings and can also be present simultaneously, compounding the challenge of accurate diagnosis [8] .…”

Chondroblastomas in Children and Young Adults: Revision of 55 Cases

“…The most common clinical presentation in our series was pain, which is the typical presentation according to the literature. [1][2][3]5,6 The presentation in unusual locations of chondroblastomas, as well as similar clinical presentation and imaging characteristics with GCTs and aneurysmal bone cysts, can make the diagnosis challenging, as shown by Zheng et al 9 Therefore, it is imperative that the clinician keeps a high index of suspicion for chondroblastoma to make an accurate diagnosis.…”

Images of giant cell tumor and chondroblastoma around the knee: retrospective analysis of 99 cases

“…Chondroblastoma is a rare primary benign osseous tumor that accounts for approximately 1% of all bone neoplasms, affecting mostly children and young adults in the second and third decades of life (8,9). Typically, chondroblastoma is located in the medullary cavity of the long bone epiphyses and apophyses, and is rarely found in the cortex or long bone metaphysis (8,9). The imaging features of these 2 tumors reported in previous studies (7,(10)(11)(12)(13)(14)(15)(16)(17) are summarized in Table 1.…”

“…GCTBs have many common features on imaging with chondroblastoma and may present a challenge in terms of a correct diagnosis. Chondroblastoma is a rare primary benign osseous tumor that accounts for approximately 1% of all bone neoplasms, affecting mostly children and young adults in the second and third decades of life ( 8 , 9 ). Typically, chondroblastoma is located in the medullary cavity of the long bone epiphyses and apophyses, and is rarely found in the cortex or long bone metaphysis ( 8 , 9 ).…”