Giant cell tumour

Introduction

A benign but aggressive tumor of unknown origin that is usually found in the epiphysis of long bones  Age more common in females (unlike most bone tumors) ages 20-40 years (80% of giant cell tumors occur in patients older than age 20 years, with the peak incidence in the third decade of life) patient age/gender on previous OITE questions: 17F, 21M, 27F, 34F, 36F, 40M  Location 50% around knee (distal femur or proximal tibia), most common location  10% in sacrum and vertebrae (sacrum is most common site in axial skeleton)  distal radius is third most common location phalanges of the hand is also a very common location Malignant potential as primary malignant giant cell tumor metastasizes to lung in 2%  hand lesions have greater chance of metastasis secondary malignant giant cell tumor occurs following radiation or multiple resections of giant cell tumor Differential If multiple lesions (~1%) than rule out hyperparathyroidism

Symptoms

Presentation   pain referable to involved joint

Imaging

Radiographs lytic and destructive metaphyseal lesion that often extends into the epiphysis and often borders subchondral bone  may have cortical thinning with breakthrough Bone scan is very hot  MRI shows clear demarcation on T1 image between fatty marrow and tumor

Histology

Characteristic findings basic proliferating cell type is the mononucleur spindle-shaped stromal cell  hallmark Giant cells are numerous  nucleus of giant cell appears same as spindle-shaped stromal cells

Treatment

Operative extensive curettage with chemical cauterization (phenol), bone grafting and cementing  challenge of treatment is to remove lesion while preserving joint and providing buttress support to subchondral joint aggressive exterioration of overlying cortex is required  10-30% recurrence with curettage alone verses 3% with cementation hand lesion treatment is controversial if no cortical breakthrough treat with curettage and cementing if significant cortical breakthrough consider intercalary resection (with free fibular graft) vs. amputation radiation alone for inoperable lesions only leads to 15% malignant transformation