Brown tumors - hyperparathyroidism

Case contributed by Dalia Ibrahim

Presentation

Pelvic pain and limbing.

Patient Data

Age: 15 years
Gender: Female

An expansile altered marrow signal of the left superior pubic body and superior pubic ramus eliciting low T2 with tiny cystic hyperintense foci of high signal. It is seen associated with markedly thinned out cortex and mild cortical erosions, yet no extra-osseous soft tissue components.

A similar smaller lesion is seen implicating the right inferior pubic ramus.

Bilateral inferior pubic ramus stress fractures and surrounding edema.

The characteristic low T2 signal and tiny internal cysts as well as the bilateral inferior pubic rami stress fractures were both suggestive of hyperparathyroidism and brown tumors.

  • osteomalacia of the examined bones

  • Left pubic and smaller right iliac and right inferior pubic ramus lytic lesions (likely brown tumors)

  • bilateral inferior pubic rami stress fractures

  • bilateral erosive changes of the articular surfaces of both sacroiliac joints

  • subperiosteal resorption of the medial aspect of the left femoral neck

CT findings confirmed the previous possibility of hyperparathyroidism and brown tumors.

The patient had elevated parathyroid hormone levels (321 pg/ml) and alkaline phosphatase (620U/L) and normal serum calcium levels.

The physician recommended a parathyroid scan.

Parathyroid sestamibi scan

Nuclear medicine

Normal parathyroid scan. No evidence of parathyroid adenoma.

Erosive changes of the sternal ends of both clavicles.

An irregular-shaped soft tissue lesion is seen at the suprasternal region abutting the aortic arch and the brachiocephalic artery, probably representing ectopic parathyroid adenoma.

An irregular-shaped soft tissue lesion is seen at the suprasternal region abutting the aortic arch and the brachiocephalic artery, probably representing ectopic parathyroid adenoma.

Annotated image

The first image shows multiple features of hyperparathyroidism including giant cell tumors of the iliac bones, osteomalacia of the examined bones, stress fractures of the inferior pubic rami, bilateral erosive changes of the articular surfaces of both sacroiliac joints, subperiosteal resorption of the medial aspect of the left femoral neck and erosive changes of the medial sternal heads.

The second image shows an ectopic parathyroid tissue at the suprasternal region on CT and MRI.

Case Discussion

The case illustrates the radiological features of hyperparathyroidism including giant cell tumors at the iliac bones, osteomalacia of the examined bones, stress fractures of the inferior pubic rami, bilateral erosive changes of the articular surfaces of both sacroiliac joints, subperiosteal resorption of the medial aspect of the left femoral neck and erosive changes of the medial sternal heads.

99mTc sestamibi (99mTc-MIBI) imaging gave a false negative study and failed to localize the parathyroid adenoma.

However, CT and MRI of the neck showed an irregular-shaped lesion at the suprasternal region showing mixed fatty and solid texture.

The patient later underwent surgical resection of the suprasternal parathyroid tumor and the pathological diagnosis was parathyroid adenoma.

False negative 99mTc sestamibi results might be secondary to small tumor size, cystic components, multiglandular disease, and the site of parathyroid adenoma. In this case, other imaging modalities such as 4D CT, US, MRI, or even venous sampling might help to localize parathyroid adenomas.

How to use cases

You can use Radiopaedia cases in a variety of ways to help you learn and teach.

Creating your own cases is easy.