Meningioma on bone scan

Case contributed by Dr Jan Frank Gerstenmaier

Presentation

Staging for breast cancer

Patient Data

Age: 70 years
Gender: Female
Nuclear medicine

Staging bone scan

This patient was newly diagnosed with infiltrating ductal carcinoma, and underwent a bone scan as part of her staging.

99mTc-HDP bone scan full body anterior and posterior scans, and right and left lateral views of the skull demonstrate focal increased radiotracer uptake in the right calvarium.

Clearly the abnormality in the right frontal skull was concerning for an osteoblastic metastasis from the ductal carcinoma. The patient underwent MRI brain for further characterization.

MRI

Contrast-enhanced MRI brain

MRI brain demonstrates a well-defined extra-axial mass overlying the right frontal lobe. The mass enhances avidly following intravenous gadolinium. A dural tail in shown. There is no significant mass effect or oedema in the frontal lobe. A small area of low signal is seen in the adjacent calvarium.

The extra-axial mass corresponds to the lesion seen on bone scan, and appearances are consistent with a meningioma.

Case Discussion

Extraosseous uptake of bone seeking radiotracers can occur in lesions with calcification demonstrated histologically or radiologically; or else in lesions with acute tissue necrosis, but without evidence of calcification. Calcified meningiomas and cerebral infarction are examples of these two categories. Radiotracer uptake in meningiomas is caused by three known factors affecting calcium deposition (1):

  • tumor calcification
  • calvarial erosion
  • formation of reactive bone

In this case, there is a small area of low signal in the adjacent cavarium which likely represents the formation of reactive bone, giving rise to focal increased radiotracer uptake. On MR, there is no evidence of tumoral calcification. Unfortunately, a CT is not available at this time to confirm.

Meningiomas are common, and occasionally seen on bone scan. There are several published case reports of meningiomas incidentally picked up on bone scan, most commonly during the work-up for breast cancer (2, 3). The appearances on bone scan are non-specific, therefore cross sectional imaging (CT or MR) is necessary to further characterize these lesions.

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Case information

rID: 21402
Case created: 20th Jan 2013
Last edited: 21st Feb 2016
Inclusion in quiz mode: Included

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