Giant Cell Tumor

Abstract

Giant cell tumor (GCT) is a locally highly aggressive tumor of bone comprising 5 to 10% of all benign bone tumors. The sacrum is the third most common site of involvement. Patients with sacral GCTs present with localized pain in the lower back that may radiate to one or both lower limbs. Vague abdominal complaints and bowel and bladder symptoms may also be present. Neuroimaging workup should include advanced modalities, preferably magnetic resonance imaging, prior to obtaining a biopsy specimen. Giant cell tumor has a 1 to 5% rate of metastasizing to the lung and may convert to a fulminate malignant variant, which has a very poor prognosis. The standard treatment for GCT is curettage combined with adjuvant bone grafting or cement-augmented stabilization. In appropriately selected cases, sacral resection is a valuable procedure to effect local tumor control and overall survival. Embolization may also prove palliative and/or curative in cases in which the tumor is unresectable or refractory to treatment.

Introduction

It is important for spine and sarcoma surgeons to appreciate GCTs of the sacrum. In this paper I will review this entity, providing an overview and discussion of its presentation, diagnostic workup, and treatment.

Giant cell tumor is a locally very aggressive tumor of bone. The sacrum is the third most common site of involvement of GCTs after the knee and radius. Although generally classified as a benign tumor, GCTs involved with the sacrum are associated with high morbidity. Standard treatments, including surgery and irradiation, are associated with significant complications and recurrence rates. Treatment of sacral lesions is particularly problematic because of their relatively advanced clinical presentation and surrounding anatomical constraints.

Generally GCTs comprise between 5 and 10% of all benign bone tumors, occurring most frequently in the third decade of life. They are more common in females than in males. Giant cell tumors may present as either Enneking Stage 2 or Stage 3 disease and, less frequently, as Stage 1.^[4]

Presenting Signs and Symptoms

When GCTs are involved with the sacrum, patients present with localized low-back pain that may radiate to one or both lower limbs. Neurological symptoms, if present, are often subtle.^[11] Vague abdominal discomfort, early satiety, and a change in bowel/bladder habits are possible. The onset of symptoms is generally insidious; the patient most frequently complains of a slowly progressive problem over several months.

Diagnostic Workup

After obtaining a thorough patient history, the physician should conduct a complete physical examination including abdominal, neurological, spine, and rectal vault assessment. Plain radiography frequently fails to reveal the true extent of the disease (Fig. 1 upper). Axial CT scanning (Fig. 1 center) or, preferably, magnetic resonance imaging (Fig. 1 lower) is necessary for a full evaluation of the anatomical characteristic of the tumor and its invasion into surrounding structures. Bone scintigraphy demonstrates nonspecific increased activity but is recommended in the workup and staging of GCT^[5] as well as other aggressive sacral tumors to evaluate noncontiguous disease. Multi-level spinal involvement has been reported in cases of GCT.^[6] Furthermore, these lesions have been reported as a purely soft-tissue mass involving only the sacral canal without osseous involvement.^[15]

Abstract and Introduction

Abstract

Introduction

Presenting Signs and Symptoms

Diagnostic Workup