radiation oncology seminar

1. Anatomy of
Larynx
(with Radiology),
Diagnostic
Workup,Staging.
Presenter – Dr Renu
Moderator- Dr Roopali Ma`am

2. ANATOMICAL LOCATION & EXTENT
• Anterior midline of neck – root of tongue to
trachea
• C3- C6 cervical vertebrae in adult males ,
little higher in females
SUPERIORLY-- Tip of epiglottis, lateral borders
of epiglottis, laryngeal aspect of AEF,
Arytenoid region,interarytenoid space
INFERIORLY– plane passing through inferior
Edge of cricoid cartilage

3. DIVISIONS OF LARYNX
SUPRAGLOTTIS
Suprahyoid epiglottis
Infrahyoid epiglottis
False vocal cords
Lat. n sup. surface of
ventricles
AEF
Aryteniods
GLOTTIS
True vocal cords
Anterior
commissure
SUBGLOTTIS
2cm long,
extends 10mm
below the
ventricular apex
to lower margin
of cricoid
cartilage

4. • SHELL (FRAMEWORK) OF LARYNX—
formed by 1) hyoid bone
2) thyroid cartilage
3) cricoid cartilage
CARTILAGES OF LARYNX
UNPAIRED CARTILAGES
1) THYROID
2) CRICOID
3)EPIGLOTTIS
PAIRED CARTILAGES
1) ARYTENOIDS
2)CORNICULATE
3)CUNEIFORM

5. • The pre-epiglottic and paraglottic fat
spaces are essentially contiguous space
lying between the external framework of
the thyroid cartilage and hyoid bone and
the inner framework of the epiglottis and
intrinsic muscles
• There are thin membranous septa between
these spaces , capable of holding a tumor in
check to a limited degree.
• The space is traversed by blood and
lymphatic vessels and nerves. Because few
capillary lymphatics arise in this area,
invasion seldom leads to metastases.
• The fat space is limited by the conus
elasticus inferiorly, the thyroid ala, the
thyrohyoid membrane, the hyoid bone
anterolaterally, the hyoepiglottic ligament
superiorly, and the fascia of the intrinsic
muscles on the medial side.
• Posteriorly, it is adjacent to the anterior
wall of the pyriform sinus.
• Seen as low density areas on CT.
SPACES IN LARYNX

6. Membranes of larynx
INTRINSIC EXTRINSIC
1.Cricovocal – forms vocal
ligaments/ TRUE VC
2.Quadrangular –
formsvestibular ligament/
FALSE VC
1. Thyrohyoid
2. Cricothyroid
3. Cricotracheal

10. Blood Supply
• Upto vocal folds –
superior laryngeal
vessels
Below vocal folds-
inferior laryngeal
vessels

11. Nerve Supply

12. Lymphatics
Supraglottic
rich lymphatic network.
• High propensity for b/l LN mets due to midline location.
• Mainly in Jugulodigastric L N ( level II)
• Few into level III LN
• Level V seldom involved.
• Level 1b and 1a almost never involved
Glottis
• Essentially no lymphatics
• Thus tumor spread occurs only when supra- n sub-glottis involved
Subglottis
• Pretracheal ( Delphian ) nodes in the region of thyroid isthmus
• Also paratracheal level VI LN & level IV LN

13. Epidemiology
• About 2% of total cancer burden
• Accounts for 0.3% of all cancer deaths
• Approx 25% of head and neck tumors
• Ratio of glottic to supraglottic Ca is approx. 2:1
• Subglottic cancers are rare
• 80% occur in men.
• Age group 40- 70 yrs.
• Most curable of upper aerodigestive tract cancers
• 7th m/c cause of cancer in males
RISK FACTORS
• Strong association with cigarrate smoking
• a/w tobacco chewing
• a/w heavy marijuana smoking
• Role of alcohol in provoking laryngeal cancer remains unclear

14. Clinical Presentation
• Hoarseness
• Most common symptom
• Small irregularities in the vocal fold result in voice changes
• Changes of voice in patients with chronic hoarseness from
tobacco and alcohol can be difficult to appreciate.
• CA true vocal cords– produces Hoarseness at very early stage

15. Supra glottis Ca
• Often silent
–most frequent initial symptom is Mild odynophagia
• Described as Sore throat or lump in throat by patient
• Otalgia- referred pain by Arnold branch of Vagus
• Sensation of foreign body
• Difficulty in swallowing
• LATE SYMPTOMS –Halitosis, weight loss,
dysphagia, aspiration
• Most frequent location for cancers in supraglottic
larynx- Epiglottis
• Exophytic and circumferential mass lesions.
• Adjacent sites may be involved leading to fixation of
larynx—d/t involvement of either Cricoarytenoid ms/
joint, or, rarely , d/t RLN

16. Glottic Carcinomas
• True vocal cords - m/c site of laryngeal carcinomas
• Anterior portion of the true vocal cord -m/c location of squamous cell cancer.
• Most lesions - along the free margin of the vocal cord
• At the time of diagnosis, 2/3rd are usually u/l
• If b/l then AC involvement is certain

17. Sub-glottis Carcinomas
• Rare and account for only 5% of all
laryngeal carcinomas.
• Most circumferential lesion often
involving the undersurface of the true
vocal cords at the time of diagnosis
• A tendency for early invasion of the
cricoid cartilage .

18. Routes of spread
LOCAL SPREAD-
• No anatomical barrier to growth from one area to another.
• Involvement of vocal cords on the external epithelial surface is a late phenomenon but sub mucosal
extension by way of para glottic space occur early.
• Fat space is an important venue for submucosal spread of infrahyoid epiglottis, false cord and true
cord lesions.
• Incidence of clinically positive nodes at the time of diagnosis is 55% except for VC carcinoma
( ~0 %-2% upto T2 N 20-30% In c/o T3/T4)
DISTANT METASTASIS
• Incidence is very low.
• Identified in approx. 10 to 20% cases, majority have supraglottic or subglottic primary.
• Lung(60%) is m/c site followed by bones(20%) and liver(10%).
• Brain mets very rare.

20. • Good neck examination looking for cervical lymphadenopathy and broadening of
the laryngeal prominence is required
• The base of the tongue should be palpated for masses as well
• Restricted laryngeal crepitus may be a sign of post cricoid or retropharyngeal
involvement
 extralaryngeal spread -
- palpation of diffuse firm fullness above the thyroid notch with widening of
- space between hyoid and thyroid indicate invasion of preepiglottic space.
- growth through cricohyoid membrane may produce midline swelling.
- thyroid cartilage invasion may cause perichondritis and on palpation may
be tender .
EXAMINATION -

21. Indirect Laryngoscopy
DONE – 1. TO SEE APPEARANCE OF LESION
2. V C MOBILITY
3. EXTENT OF DISEASE

22. Direct Laryngoscopy
DONE TO SEE
1. HIDDEN AREAS OF LARYNX-
INFRAHYOID EPIGLOTTIS,
AC,SUBGLOTTIS,VENTRICLE
2. EXTENT OF DISEASE

23. MICROLARYNGOSCOPY

24. CT SCAN
• CT scan with contrast enhancement is the method of choice
• Preferably done before biopsy.
• In cancers of the larynx, cross-sectional imaging with CT provides valuable
information regarding primary tumor staging and treatment.
• Retropharyngeal adenopathy, not apparent on physical examination , usually
appreciated on CT.
• CT is excellent for determining -
 subglottic extension
 extension outside the larynx into the soft tissues of the neck and
 has potential for determining thyroid or cricoid cartilage invasion,
 Viewing pre- n para- epiglottic fat spaces
 Better than MRI as longer scanning time results in motion artifacts
 CECT helps to outline blood vs n the thyroid gland

25. MRI
• Has value in defining
- subtle exo-laryngeal spread
- or more accurate assessment of cartilage invasion, pre epiglotic and paraglottic
extension.
- Or Extent of tracheal and/or esophageal invasion.
• Gross cartilage invasion can be detected on CT; however, early cartilage
abnormalities are detected better on MRI.
• Areas of cartilage involvement result in high signal intensity on T2W images and
contrast-enhanced T1W images.
PET SCAN
• Useful in :
• detection of occult nodal and distant mets.
• To distinguish between recurrence and post treatment change
• PET/CT is the modality of choice for therapy assessment and is performed 12
weeks after completion of chemo-radiation.

31. THANKYOU