📄

Incidental Spleen / Lymph Node (ACR)

Guided recommendation from the ACR Incidental Findings Committee II white paper on splenic and nodal findings (Heller et al., JACR 2013, Part 3, Figs 1-2). For incidental CT/MRI findings.

Encodes the ACR Incidental Findings Committee II splenic (Fig 1) and nodal (Fig 2) flowcharts. Applies to incidentally detected CT/MRI findings; symptomatic, biopsy-proven or staging findings are not incidental. Recommendations, not standard of care.

Reference — ACR Splenic & Nodal white paper (Figs 1-2)

Heller MT, Harisinghani M, Neitlich JD, Yeghiayan P, Berland LL. Managing Incidental Findings on Abdominal and Pelvic CT and MRI, Part 3: White Paper of the ACR Incidental Findings Committee II on Splenic and Nodal Findings. J Am Coll Radiol 2013;10:833-839.

Spleen (Fig 1). Diagnostic benign = cyst (imperceptible wall, near-water <10 HU, no enhancement) or hemangioma. Benign imaging features = homogeneous, low attenuation (<20 HU), no enhancement, smooth margins. Indeterminate = heterogeneous, intermediate attenuation (~20 HU), enhancement, smooth margins. Suspicious = heterogeneous, enhancement, irregular margins, necrosis, splenic parenchymal/vascular invasion, substantial enlargement. Evaluate = PET vs MRI vs biopsy. Indeterminate / history-of-cancer <1 cm → follow-up MRI at 6 and 12 months.

Lymph nodes (Fig 2). Benign = normal short-axis (<1 cm in retroperitoneum), elongated fatty hilum, normal enhancement, normal number. Suspicious = short-axis ≥1 cm, round/indistinct hilum, necrosis/hypervascular, or cluster of ≥3 nodes in one station or ≥2 nodes in ≥2 regions. Other evaluation = PET/CT, nuclear scintigraphy (MIBG), or endoscopic ultrasound.