Chondroblastoma of the Patella: A Case Report

Ben Romdhane Majdi,Chebbi Wael,Mbarek Mondher,Kedous Mohamed Ali,Rebhi Safouen,Boujelbene Nadia

doi:10.4172/2471-8556.1000149

Abstract

Chondroblastoma is a rare bone tumor of cartilaginous origin representing less than 1% of all the primitive bone tumors. This lesion usually develops in the epiphysis of long bones and occurs during the second decade of life. However, there are rare atypical localizations like the patella. We report an atypical case of chondroblastoma of the patella and discuss the clinical, radiological and therapeutic features of this rare location. A young 20-year-old patient consulted for right knee pain evolving for 2 months with a discreet knee effusion and pain on palpation of the patella. The radiological and CT showed lytic lesion of the distal half of the patella, lobulated, with sclerotic outlines and blowing the internal cortex. The patient underwent surgery with curettage and filling with autologous iliac cancellous bone graft. Histological examination led to the diagnosis of chondroblastoma. At last follow-up, 18 months, the patient had a normal function of his knee with no recurrence for radiological control. The location of chondroblastoma in the patella is exceptional but its radiological features resemble those of usual epiphyseal locations. The most popular treatment is curettage associated with cancellous bone grafting and thus to avoid the functional consequences of a patellectomy.

Highlights

Chondroblastoma is a rare benign cartilaginous bone tumor representing less than 1% of all primary bone tumors
We report an atypical case of chondroblastoma of the patella and discuss through our observation and a review of the literature the clinical, radiological and therapeutic features of this rare localization
The functional prognosis of chondroblastoma depends on its location, its degree of aggressiveness that may be responsible for joint destruction or an extension to a nearby bone, and in children, the involvement of the growth plate may lead to growth defect of the bone segment and shortness of a limb [9]

Summary

Introduction

Chondroblastoma is a rare benign cartilaginous bone tumor representing less than 1% of all primary bone tumors. There are rare atypical localizations like the patella. We report an atypical case of chondroblastoma of the patella and discuss through our observation and a review of the literature the clinical, radiological and therapeutic features of this rare localization. Microscopic examination revealed a sheet-like proliferation of small to intermediate-sized round polygonal cells within a chondroid matrix (Figure 5a). At the 18-month follow-up, the clinical results were rated excellent on functional criteria with total indolence and mobility at 0/140 of the right knee. Figure 5a: A sheet-like proliferation of small to intermediate-sized round polygonal cells with scattered osteoclast-type giant cells (Hematoxylin-eosin, original magnification 100x). Figure 5b: Nucleus is centrally placed with longitudinal nuclear groove (Hematoxylin-eosin, original magnification 1000x)

Discussion

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Conclusion