The role of Tc-99m MIBI scintigraphy in clinical T1 renal mass assessment: Does it have a real benefit?

• Published in: Urologic oncology 2020-12, Vol.38 (12), p.937.e11-937.e17
• Main Authors: Asi, Tariq, Tuncali, Meltem Çağlar, Tuncel, Murat, Alkanat, Nazli Eylem İmamoğlu, Hazir, Berk, Kösemehmetoğlu, Kemal, Baydar, Dilek Ertoy, Akdoğan, Bülent
• Format: Article
• Language: English
• Subjects: Benign vs. malignant; MDR pump; Oncocytoma vs. RCC; Renal mass; Tc-99m MIBI scintigraphy
• ISSN: 1078-1439; 1873-2496
• DOI: 10.1016/j.urolonc.2020.07.018

•Renal masses with negative Tc-99m sestamibi uptake are highly suspicious for malignancy.•Renal masses with positive Tc-99m sestamibi uptake have a good possibility to be benign.•Chromophobe and oncocytic papillary variants RCC lesions appear positive on Tc-99m sestamibi scintigraphy.•Tc-99m sestamibi scintigraphy performed as an adjutant to preoperative imaging is beneficial in managing indeterminate renal lesions. Despite the increasing accuracy of imaging modalities, the rate of benign renal tumors misclassified as malignant before surgery still non-negligible. Tc-99m sestamibi was demonstrated to be a possible reliable agent in discriminating oncocytoma from renal cell carcinoma (RCC). We aimed to study the efficacy of Tc-99m MIBI tumor scintigraphy in evaluating clinical T1 renal masses. Between July 2017 and March 2019, patients with clinical T1 renal mass underwent preoperative Tc-99m sestamibi tumor scintigraphy. Tc-99m sestamibi tumor scintigraphy findings were correlated with the postoperative pathology results. A total of 90 renal masses were included in the study. Male to female ratio was 67/23. The mean age and tumor size were 55.5 ± 11.4 years and 4 ± 1.4 cm, respectively. In pathological evaluation, 20% (18/90) of masses were reported as benign (10 oncocytomas, 4 angiomyolipomas (AML), 2 chronic sclerosis, 1 fibroma and 1 hydatid cyst). While Tc-99m sestamibi uptake was positive in all oncocytomas; 6 patients with chronic sclerosis, fibroma, hydatid cyst and angiomyolipoma pathologies had no uptake. Except for 5 chromophobe cell RCC and 3 oncocytic papillary RCC masses, malignant lesions had no uptake. In predicting benign pathology, Tc-99m sestamibi tumor scintigraphy had positive and negative predictive value of 60% and 91.3%, respectively. The mean Tc-99m 2-methoxy isobutyl isonitrile lesion/normal renal parenchyma ratio of benign and malignant lesions was 0.6 and 0.37, respectively. A relative uptake of 0.49 was an acceptable cutoff point to discriminate oncocytomas from all other pathologies. Tc-99m sestamibi tumor scintigraphy has a beneficial role in the assessment of clinical T1 renal mass. Masses with negative uptake harbor high probability of being malignant. While evaluating masses with positive uptake, it should be kept in mind that some malignant pathologies may demonstrate similar results.