Multiple Brown Tumours in a patient with chronic renal failure (ECR 2010 Case of the day)

Clinical History

We present the case of a 63 year old male with a chronic medical illness presents complaining of left shoulder pain.

Imaging Findings

Radiographs of the clavicles (Fig. 1-2, right and left respectively), demonstrate expansile, centrally lucent lesions peripherally, but separate from the acromioclavicular joint.

CT thorax (Fig. 3-4) demonstrates the left sided clavicular lesion to be expansile and centrally lytic (Fig. 3), and also shows a further similar lesion anteriorly in a left sided rib (Fig. 4).

Radiographs of the forelegs (Fig. 5-6, right and left respectively) demonstrate further, similar lesions throughout each tibia, which, when compared with previous radiographs had remained stable over a period of five years. (Additional information to be gleaned from Fig. 5 is the presence of vascular calcifications and vascular clips, providing a clue to the underlying Diabetes and consequent vasculopathy, eventually leading to renal failure, and ultimately renal osteodystrophy).

Discussion

Patients with renal failure often undergo hypertrophy of the hyperparathyroid glands induced by hyperphosphataemia due to decreased renal excretion. Consequently increased Parathyroid hormone (PTH) alters bone metabolism leading to a promotion of osteoclasts, osteoblasts and osteocytes, giving rise to bone resorption, periosteal reactions and Brown tumors.

The changes associated with renal osteodystrophy are in many cases reversible following renal transplantation; however, this may take years.

Hyperparathyroidism:

• Subperiosteal resorption of bone produces lace-like irregularity of the cortical margin progressing to scalloping and spiculation. Seen in the tufts of the distal phalanges and also seen at other sites e.g. diametaphyses of the middle phalanges (radial aspects), inferior surface of ribs and calcaneus, medial proximal tibia, humerus and femur, and the inferior clavicles, particularly distally [1, 2, 3].

• Juxtaarticular erosions, particularly likely to be manifested in the hands and feet, as well as resorption of the lamina dura around the teeth [4].

• Manifestations of osteoporosis: intracortical resorption and a tunneling appearance secondary to intra-haversian osteoclasis.

• Endosteal bone resorption seen in the upper extremities, particularly the hands, as scalloped areas along the cortex. When multiple in the skull, they give rise to the classic “salt and pepper” appearance.

• Subtendinous and subligamentous resorption: surface scalloping at entheses which may be either smooth or irregular, most frequent on the inferior calcaneus, the greater/lesser trochanters and the anterior inferior iliac spine. Resorption of adjacent ligaments and tendons may occur [5].

Brown tumors:

• Also referred to as osteoclastomas, represent accumulations of giant cells and fibromatous material which produce destructive, often expansile lesions in bone. These are particularly frequent with primary hyperparathyroidism; however, most are seen in relation to secondary hyperparathyroidism as this is far more common. While Brown tumours can be painful, this is usually only a feature when bone expansion and/or pressure on local neurovascular structures occurs.

• Often solitary but may be multiple. Frequently eccentric or cortical in the long bones, giving rise to endosteal scalloping and expansion. Most frequently seen in the ribs, pelvis, facial bones and femora. They may heal following correction of the underlying condition, demonstrating calcification, sclerosis and eventual disappearance. Rarely, when an autonomous adenoma develops (Tertiary Hyperparathyroidism), surgical excision of the adenoma may be required to effect healing.

Osteosclerosis:

• Trabeculae often appear coarsened in patients with renal osteodystrophy due to resorption of secondary trabeculae. Often diffuse, affecting the entire skeleton, in its initial stages manifested as increased density along the vertebral end-plates producing a so-called “rugger-jersey” spine appearance.

Differential Diagnosis List

Final Diagnosis

Multiple Brown tumours in a patient with Renal osteodystrophy (Secondary hyperparathyroidism).

URL:	https://www.eurorad.org/case/8977
DOI:	10.1594/EURORAD/CASE.8977
ISSN:	1563-4086