Two cases of mimics of bone metastasis in breast cancer

Abstract

In patients with breast cancer, the appearance of sclerotic bone lesions on imaging should raise the suspicion of skeletal metastases. However, before making the diagnosis it is important to consider the clinical context and remember that there are conditions that can mimic bone metastasis. We present two cases of mimics of bone metastasis: systemic mastocytosis and osteopoikilosis. These cases demonstrate clinical and radiological characteristics that would make a diagnosis of bone metastasis less likely, and highlight the need for an awareness of mimics of bone metastasis.

Figure 1.

Additional imaging requested to investigate increased density in the lumbar spine on DEXA scan of a 57-year-old female with early-stage breast cancer (Case 1). (a) X-ray of lumbosacral spine showing focal bony sclerosis at T12 and L1. (b) Sagittal section of CT of lumbosacral spine showing sclerotic lesions in L1 to L4. (c) Sagittal T₁ section of MRI of lumbosacral spine showing corresponding low signal lesions in the vertebral bodies.

Figure 2.

Isotope bone scan for a 57-year-old female with early stage breast cancer (Case 1) showing subtle focal uptake in L1, possibly L3, left sacroiliac joint, left iliac bone and left acetabulum. There was surprisingly little uptake considering the X-ray appearances. Potential explanations provided for the relative lack of uptake on the bone scan were: inactive metastatic disease, perhaps in response to Letrozole; or an aggressive osteoclastic component masking uptake.

Figure 3.

Isotope bone scan of a 50-year-old female with node-positive breast cancer (Case 2) showing subtle increased uptake in the left anterior chest consistent with recent breast surgery but no evidence of bone metastases.

Figure 4.

X-ray of pelvis of a 50-year-old female with node-positive breast cancer (Case 2) showing multiple sclerotic lesions in the iliac wings and proximal femora.

Figure 5.

CT scan of a 50-year-old female with node-positive breast cancer (Case 2). (a) Axial CT image of the thorax showing multiple, small, rounded sclerotic foci in the T7 vertebral body. (b) Sagittal CT image showing multiple, small, rounded, sclerotic lesions throughout the vertebra and sternum.