Paradoxical scintigraphy bone scan findings with malignancy-associated extreme hypercalcemia

Area of Science:

• Oncology
• Endocrinology
• Radiology

Background:

• Metastatic breast cancer diagnosis can present with diverse initial symptoms.
• Hypercalcemia, elevated calcium levels in the blood, is a known complication of malignancy but rarely the primary presenting feature.

Observation:

• A patient presented with extreme hypercalcemia (serum calcium >6.0 mmol/L) as the initial manifestation of de novo metastatic breast cancer.
• Initial imaging identified a significant breast mass and extensive bone metastases.
• Whole body bone scintigraphy revealed unexpected radiotracer uptake in the lungs, liver, and kidneys.

Findings:

• The patient's breast cancer was estrogen receptor (ER) positive.
• The widespread extraosseous radiotracer uptake observed on bone scintigraphy is a rare phenomenon directly linked to profound hypercalcemia.

Implications:

• This case highlights the importance of considering metastatic breast cancer in patients presenting with severe, unexplained hypercalcemia.
• The unusual scintigraphy findings underscore the systemic effects of extreme hypercalcemia in metastatic disease.
• Early recognition and management of hypercalcemia are crucial for patients with de novo metastatic breast cancer.