Incidental 4 mm solid nodule, 54-year-old low-risk patient. Fleischner 2017 recommends:
CT at 12 months; CT at 6–12 months; No routine follow-up; PET-CT
Answer: No routine follow-up. Single solid nodules under 6 mm in LOW-risk patients need no routine follow-up — the estimated cancer risk is under 1%. In a HIGH-risk patient an optional CT at 12 months may be considered, but it is not mandatory.
Same 4 mm solid nodule, but the patient is a heavy smoker with upper-lobe predominant emphysema. Now what?
Biopsy; Still nothing, ever; Optional CT at 12 months; CT at 3 months
Answer: Optional CT at 12 months. High-risk changes the <6 mm single solid answer from 'none' to an OPTIONAL CT at 12 months. Suspicious morphology or an upper lobe location are the features that justify exercising the option.
Incidental 7 mm solid nodule, single, low-risk patient:
PET-CT now; No follow-up; CT at 6–12 months, then consider CT at 18–24 months; CT at 3 months
Answer: CT at 6–12 months, then consider CT at 18–24 months. 6–8 mm single solid nodules get CT at 6–12 months, then consider a further CT at 18–24 months. In high-risk patients the second scan is recommended rather than merely considered.
Incidental 9 mm solid nodule. The Fleischner options do NOT include:
Tissue sampling; Routine CT in 24 months as the only action; CT at 3 months; PET-CT
Answer: Routine CT in 24 months as the only action. Over 8 mm the pathway accelerates: consider CT at 3 months, PET-CT, or tissue sampling depending on malignancy probability. Parking it for two years is not among the options.
Pure ground-glass nodule, 5 mm, incidental:
CT at 6–12 months; CT every 2 years for 5 years; Resection; No routine follow-up
Answer: No routine follow-up. Pure GGNs under 6 mm need no routine follow-up. At ≥6 mm: CT at 6–12 months to confirm persistence, then every 2 years until 5 years — slow-growing lepidic lesions need the long runway.
Pure ground-glass nodule, 9 mm, confirmed persistent at the 6-month CT. Correct ongoing schedule:
CT every 2 years until 5 years; Annual CT for 2 years; PET-CT; Stop — persistence proves benignity
Answer: CT every 2 years until 5 years. Persistent ≥6 mm pure GGNs are followed every 2 years UNTIL 5 YEARS. Persistence does not end surveillance; growth or a new solid component ends the watching and starts the workup. PET is poor for pure ground glass.
Part-solid nodule, 8 mm total, solid component 3 mm, persistent at 3–6 month CT:
Stop surveillance; CT every 2 years; Immediate biopsy; Annual CT for 5 years
Answer: Annual CT for 5 years. Persistent part-solid nodules ≥6 mm with a solid component under 6 mm get ANNUAL CT for 5 years. The solid component is the malignancy driver: once it reaches 6 mm, the lesion is highly suspicious and the pathway leaves surveillance.
Part-solid nodule with an 8 mm solid component:
Annual CT for 5 years; CT in 2 years; Highly suspicious — PET-CT / biopsy / resection discussion; 6-month CT
Answer: Highly suspicious — PET-CT / biopsy / resection discussion. A solid component ≥6 mm in a part-solid nodule carries high malignancy risk — this is the most dangerous morphology in the table and it exits surveillance.
MULTIPLE solid nodules, largest 5 mm, low-risk patient:
CT 3–6 months; CT 6–12 months; PET-CT; No routine follow-up
Answer: No routine follow-up. Multiple solid nodules under 6 mm: no routine follow-up in low-risk patients (optional 12-month CT when high-risk). Management keys off the MOST SUSPICIOUS nodule, not the count.
Multiple solid nodules, dominant one 9 mm:
Treat as metastases, no imaging; CT 3–6 months, then consider 18–24 months; No follow-up; CT at 12 months only
Answer: CT 3–6 months, then consider 18–24 months. Multiple solid with any nodule 6 mm or larger: CT at 3–6 months, then consider 18–24 months. Multiplicity shortens the first interval compared with the single-nodule row.
Which patient is OUTSIDE Fleischner 2017's scope?
62-year-old, incidental 5 mm nodule; 40-year-old never-smoker, incidental 7 mm nodule; 57-year-old with known renal cell carcinoma and a new 6 mm nodule; 70-year-old with COPD, incidental 4 mm nodule
Answer: 57-year-old with known renal cell carcinoma and a new 6 mm nodule. Fleischner excludes patients with known cancer (plus under-35s, immunocompromise, and screening CTs). A new nodule in a cancer patient is potential metastasis and follows oncologic logic, not the incidental table.
A 5 mm nodule is reported from a lung-cancer-screening LDCT. The correct framework is:
BI-RADS; Either — they are interchangeable; Fleischner 2017; Lung-RADS
Answer: Lung-RADS. Screening studies are categorized with Lung-RADS, which has its own thresholds and return intervals. Fleischner governs INCIDENTAL nodules on non-screening CTs. Citing the wrong system is a classic report error.