Significance of MIBI scintigraphy in a patient with hydatid cyst and parathyroid adenoma

17-year-old boy with hyperparathyroidism exhibited a large cyst in the lefthemi-thorax on his chest x-ray. the cyst was identified as a hydatid cyst. hewas referred for biphasic methoxy isobutyl isonitrile (mibi) parathyroid scan.a discrete ectopic parathyroid was detected in the left upper mediastinum inaddition to accumulation of the mibi tracer in the cyst wall. usingradio-guided occult lesion localization with an injection of 3 mci 99mtc - mibi in the morning of the operation day, an ectopic adenoma wasdetected with a gamma probe within the thymus, resected with a consequentdecline of serum high parathyroid hormone (pth). this report is remarkablein two different aspects: the importance of radio-guided localization ofectopic adenoma, which in this case was within the thymus, and theaccumulation of mibi in hydatid cyst wall, as a unique report of this condition.