Diagnostic Approach to Hyperdense Renal Masses

Introduction to Hyperdense Renal Masses

The American College of Radiology recommends that massas homogêneas medindo >70 HU na TC sem contraste are considered benign and do not require additional evaluation 1, 2
Lesões com sinal T1 hiperintenso homogêneo, bordas lisas e relação lesão/parênquima >1,6 on MRI predict benign cysts with an accuracy of 73,6-79,9% 3

Angiomiolipomas sem gordura macroscópica appear as hyperdense masses on non-contrast CT 2, 4
Massas that are hiperatenuantes on non-contrast CT and realçam homogeneamente após contraste have a higher probability of being angiomiolipomas pobres em gordura 2, 4
Biópsia should be strongly considered when characteristics suggestive of angiomiolipoma pobre em gordura are present, as one-third of biopsies of renal masses are benign 3, 5

The American College of Radiology suggests that massas homogêneas <20 HU or >70 HU on non-contrast CT are benign and do not require additional evaluation 1, 2
Massas entre 20-70 HU or heterogêneas on non-contrast CT are indeterminate and require additional evaluation 1
TC multifásica com contraste should be used to evaluate realce, with any realce (>10-15 HU) suggesting a solid lesion 2
TC de dupla energia can differentiate solid tumors from hyperdense cysts when a multifásico protocol is not available 1, 2

MRI has superior specificity to CT (68,1% vs 27,7%) for characterizing renal masses, but has limited capacity to detect calcifications 3, 5, 6
Biópsia percutânea is indicated when imaging characteristics suggest a benign lesion (angiomiolipoma pobre em gordura) but are not diagnostic, with significant complications being rare (0,9% in a series of 235 biopsies) 3, 5
However, a non-diagnostic biopsy result cannot be considered evidence of benignity 3, 5