Chondroblastoma of the Patella With Aneurysmal Bone Cyst

Abstract

Chondroblastoma of the patella is rare. Aneurysmal bone cysts, which develop from a prior lesion such as a chondroblastoma, are seldom seen in the patella. The authors report a case of a 36-year-old man who presented with 2 years of right knee pain without calor, erythema, pain on palpation, or abnormal range of motion. Radiological studies suggested aneurysmal bone cyst. The lesion was excised with curettage and the residual cavity filled with autogenous bone graft. Histopathology revealed chondroblastoma associated with a secondary aneurysmal bone cyst. In the follow-up period, the patient demonstrated normal joint activities with no pain. Normal configuration of the patella and bone union were shown on plain radiographs. The authors present a review of the literature of all cases of patellar chondroblastoma with aneurysmal bone cyst. This case is the 14th report of aneurysmal bone cyst arising in a chondroblastoma of the patella. According to the literature, computed tomography and magnetic resonance imaging are useful in the study of these lesions. The pathologic diagnosis is based on the presence of chondroblastoma and aneurysmal bone cyst. Treatment of this lesion includes patellectomy, curettage alone, and curettage with bone grafting. Despite the risk of recurrence of this lesion in the patella, the authors first recommend curettage followed by filling the cavity with bone graft. To protect the anterior tension of the patella intraoperatively, the bone window should be made at the medial edge of the patella to perform the curettage and bone grafting.

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

“…Pink cartilage-like matrix was also noted. All of these features are highly consistent with those of the speci c manifestations [4,5,6,23] (proliferated chondroblasts observed in the laminar regions, accompanied by cartilage matrix and some multi-nucleated cells. Calci cation may also appear in some areas) of CB.…”

“…On MRI, the lesion manifests as a lobulated lesion with a clear boundary, showing iso/hypointensity on T1-W1 images and mixed intensity or hyperintensity focus on T2-W1 images. The uid level can be seen in case of secondary ABC [4,6] . CB was featured as an integrated sclerotic bone at the margin of focus and scattered calci ed lesion, wherein the focus could extend to the subchondral bone, although it seldom entered the joint space [19] .…”

“…This type of tumors often affect the proximal epiphysis of the femur, humerus, and tibia [2,3] , while those affecting the patella are extremely rare [4,5] . Only a few cases of CB combined with secondary ABC [6] have been reported until date, and they can be easily misdiagnosed as giant cell tumor (GCT) or ABC. Very few cases of CB combined with secondary ABC have been reported previously, with the main focus being the treatment regime, but not with respect to the differential diagnosis with GCT or ABC.…”

Primary tumors of the patella

“…CB appears as lesions on the patella that caused pain either with or without swelling [ 12 - 16 ]. The pain is aggravated by physical exercises and alleviated when at rest.…”

To describe minimally invasive esophagectomy with a focus on peri-esophageal lacuna anatomy

“…Lacuna anatomy has been studied in various human organs and tissues including the cerebral ventricles [3], pericardium [4], articular cavity [5], carpal tunnel [6], tarsal tunnel [7], liver [8], nasolacrimal duct [9], esophageal submucosa [10,11] and retroperitoneal lacunae [12][13][14]. These studies were closely related to the operative approach and surgical procedure.…”