Stage by subsite (supraglottic, glottic, subglottic) and the spaces that change the T-stage: pre-epiglottic and paraglottic fat, thyroid cartilage (inner vs outer cortex), and extralaryngeal spread — then the nodes.
Orient first
- Glottic tumours rarely spread to nodes early; supraglottic tumours spread to both sides of the neck.
- Paraglottic space invasion and inner cortex erosion of the thyroid cartilage upstage to T3; through the outer cortex is T4a (verify the TNM edition).
- Vocal cord fixation is clinical — imaging shows the deep extent that explains it.
Acquire the study
- Post-contrast CT neck, 1 mm, axial reformats parallel to the true cords, during quiet breathing; optional phonation (E) series.
The manoeuvre
- Axial reformats parallel to the cords: tumour subsite and extent across the anterior commissure.
- Pre-epiglottic and paraglottic fat: replacement by enhancing tumour.
- Thyroid cartilage in bone window: sclerosis, erosion of the inner cortex, full-thickness destruction.
- Subglottic extension in mm below the cords; cricoid involvement.
- Nodes: levels II–IV and VI.
What confirms it
- Biopsy-proven squamous cell carcinoma with imaging T and N stage stated by edition.
What licenses you to exclude it
- Preserved paraglottic and pre-epiglottic fat and intact cartilage exclude deep invasion on imaging.
The classic misread
- Asymmetric ossification of cartilage called invasion — look for tumour on both sides of the cartilage.