Assess / Report

Reporting elements

• Measure and report short-axis diameter.
• Describe texture and density: homogeneous versus heterogeneous, necrosis, calcification, or fatty hilum.
• Note distribution: single station, multistation mediastinal/hilar, symmetric, or bulky.
• Report FDG uptake when PET/CT is available.
• Consider the clinical context: known cancer, infection, ILD, sarcoidosis, heart failure, or systemic symptoms.

Benign-favoring features

• Smooth borders, homogeneous attenuation, and central fatty hilum.
• Calcified nodes without a known calcifying malignancy usually suggest prior granulomatous disease.

15 mm Threshold

Short axis <15 mm

• No further evaluation is usually needed if the chest is otherwise normal and morphology is benign.
• Use caution if there are numerous small nodes, suspicious morphology, or a known malignancy.

Short axis >=15 mm

• If explainable by ILD, infection, sarcoidosis, emphysema, or cardiac disease, management depends on that underlying condition.
• If unexplained, consider clinical consultation, PET/CT, and/or 3-6 month follow-up chest CT.
• If increased on follow-up, proceed to PET/CT or tissue sampling.
• If stable or decreased on follow-up, no further nodal work-up is usually needed.

Escalation / Staging

Escalate when

• Unexplained node is >=15 mm short axis.
• Node is enlarging, bulky, heterogeneous, necrotic, or highly FDG avid.
• Known malignancy or thoracic primary is present.
• Distribution or symptoms suggest lymphoma.
• Young male with suspicious bulky mediastinal nodes raises concern for seminoma or non-seminomatous germ cell tumor.

Next steps

• Clinical consultation or specialty referral.
• Short-interval chest CT, commonly 3-6 months.
• FDG PET/CT when metabolic characterization or staging is needed.
• Tissue sampling, usually EBUS-TBNA, when malignancy is suspected.

Sources

• ACR incidental thoracic findings guidance for incidental mediastinal lymph nodes.
• IASLC lymph node map for anatomic station localization when lung cancer staging is relevant.
• Use oncologic staging pathways rather than the incidental algorithm when known malignancy is present.