Accurate preoperative size estimation of adrenal nodules is vital for diagnosis and decision-making. There is controversy about the concordance between radiological and pathological sizes of adrenal lesions. Some reports sugges that CT scans underestimate the sizes across all size subgroups. This retrospective study aims to determine if modern CT scanners accurately predict the size of adrenal masses.

Records of patients who underwent adrenalectomy (n = 51) from 2014 to 2023 were examined. The largest nodule diameters reported on CT scans were compared with final pathological size. Cases with missing data were excluded from the study. Paired two-tailed t-test was used to compare preoperative CT and pathological sizes.

Preoperative CT scans showed adrenal nodule sizes of 47 (24M:23F) patients between 7 mm to 94 mm (largest dimension). The histopathological sizes of adrenal nodules (largest dimension) varied from 7 to 100 mm with our analysis showing a size discrepancy of 0 - 17 mm. (Mean: CT size - 29.5 mm vs Pathological size - 29.9 mm, p = 0.68). Subgroup analysis of nodules (<3cm) showed that CT underestimated mean diameter (18.4mm) as compared to pathological assessment (19.4 mm p = 0.33), whilst for nodules (>3cm), CT scan overestimated the size of adrenal masses at 49.9mm as compared to 49.2mm on pathological assessment (p = 0.67).

No statistically significant difference between the sizes of adrenal nodules was detected between modern CT scanners and final pathology across all subgroups. This avoids the need to apply for any correction formulae as mentioned in older studies