A 67-year-old woman with primary hyperparathyroidism was referred to our hospital. She had taken alendronate, and laboratory tests showed hypercalcemia (11.3 mg/dL), hypercalciuria (200 mg/day), hypophosphatemia (2.2 mg/dL) and an elevated serum intact-PTH level (141 pg/mL). Technetium-99m sestamibi scintigraphy failed to detect abnormal parathyroid lesions, but ultrasonography only showed a 5×3-mm oval-shaped, well-circumscribed, hyperechoic solid nodule with blood flow on color Doppler imaging inferior to the left lower pole of the thyroid (Picture A). Because she preferred surgery to medication with cinacalcet, the hyperechoic nodule was excised, resulting in normalized serum calcium and PTH levels. The pathological diagnosis was parathyroid lipoadenoma with abundant adipose and nests of chief cells (Picture B). Ultrasound imaging shows typical parathyroid adenoma as homogeneously hypoechoic lesions surrounded by hyperechoic lines (1). However, lipoadenoma, a rare variant (0.5-1.6%) of parathyroid adenoma, sometimes presents with hyperechoic lesions, probably due to the fat-rich content (2). Attention should also be paid to hyperechoic lesions.
Picture A.
Picture B.
The authors state that they have no Conflict of Interest (COI).
References
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