[99mTc]Sestamibi SPECT Can Predict Proliferation Index, Angiogenesis, and Vascular Invasion in Parathyroid Patients: A Retrospective Study

The aim of this study was to evaluate the possible association among sestamibi uptake and the main histopathological characteristics of parathyroid lesions related to aggressiveness such as the proliferation index (Ki67 expression and mitosis), angiogenesis (number of vessels), and vascular invasion in hyperparathyroidism patients. To this end, 26 patients affected by primary hyperparathyroidism subjected to both scintigraphy with [(99)mTc]Sestamibi and surgery/bioptic procedure were retrospectively enrolled. Hyperfunctioning of the parathyroid was detected in 19 patients. Our data showed a significant positive association among the sestamibi uptake and the proliferation index histologically evaluated both in terms of the number of Ki67 positive cells and mitosis. According to these data, lesions with a higher valuer of L/N (lesion to nonlesion ratio) frequently showed several vessels in tumor areas and histological evidence of vascular invasion. It is noteworthy that among patients with negative scintigraphy, 2 patients showed a neoplastic lesion after surgery (histological analysis). However, it is important to highlight that these lesions displayed very low proliferation indexes, which was evaluated in terms of number of both mitosis and Ki67-positive cells, some/rare vessels in the main lesion, and no evidence of vascular invasion. In conclusion, data obtained on patients with positive or negative scintigraphy support the hypothesis that sestamibi can be a tracer that is capable of predicting some biological characteristics of parathyroid tumors such as angiogenesis, proliferation indexes, and the invasion of surrounding tissues or vessels.