106 Malignant tumors of larynx Flashcards
Supraglottic larynx derived from:
Glottis and subtlottis derived from:
PRIMORDIUM
From which branchial arches?
Supraglottic larynx derived from:
BUCCOPHARYNGEAL PRIMORDIUM
Third and Fourth
Blood supply
Supraglottis:
Glottis, subglottis:
Blood supply
Supraglottis: superior laryngeal arteries
Glottis, subglottis: inferior laryngeal arteries
Lymphatic drainage:
Supraglottis:
Glottis, subglottis:
Lymphatic drainage:
Supraglottis: II, III
Glottis, subglottis: VI -> IV
The
supraglottis is supplied by the superior laryngeal arteries, and
its lymphatic drainage follows these vessels to the carotid sheath
to drain into deep cervical chain nodes in levels II and III. The
glottis and subglottis are supplied by the inferior laryngeal
arteries, and similarly, lymphatic drainage from these two
regions follows these arteries to drain into prelaryngeal and
pretracheal nodes (level VI), before it reaches the deep cervical
chain nodes in level IV.3
Lymphatic drainage: unilateral vs bilateral
Glottis
Supraglottis
Glottis: Unilateral
Supraglottis: Bilateral
The glottis is formed by paired structures that fuse in the
midline. The lymphatics drain unilaterally, and the vocal folds
have sparse lymphatics; therefore glottic cancers must invade
deeply before they gain access to lymphatic channels. These
factors explain the lower incidence of lymphatic metastasis in
glottic SCC and the propensity for unilateral metastases.
Because the supraglottis is formed without a midline union, its
lymphatics drain bilaterally. The increased likelihood of bilat
eral
lymphatic metastases from supraglottic carcinoma is
ascribed to this embryologic factor.
Laryngeal framework:
Unpaired:
1.
2.
3.
Paired:
1.
Unpaired:
- Thyroid cartilage
- Epiglottis
- Cricoid
Paired:
1. Arytenoid
Boundaries of the larynx:
Superior: Anterosuperior: Anterior: - Supraglottis - Glottis - Subglottis
Inferior:
Posterior and Lateral:
Boundaries of the larynx:
Superior: tip and lateral margin of epiottis, , superior edge of aryepiglottic folds
Anterosuperior:lingual surface of the suprahyoid epiglottis, hyoepoglottic ligament
Anterior:
- Supraglottis: thyroid cartilage, thyrohyoid membrane
- Glottis: thyroid cartilage
- Subglottis: cricoid cartilage, cricothyroid membrane
Inferior: horizontal line passing across inferior edge of cricoid
Posterior and Lateral: laryngeal surface of aryepiglottic folds, arytenoids, interarytenoid space, posterior surface of the subglottic space
Forma superior boundary of preepiglottic space
Hyoepiglottic ligament
Glottis and subglottis forebearers:
from which branchial arch?
tracheobronchial primordium
sixth branchial arch
Parts of supraglottis:
suprahyoid epiglottis infrahyoid epiglottis laryngeal surface of aryepiglottic folds arytenoids false vocal cords
Boundary between supra and infrahyoid epiglottis
hyoid bone
Inferior limit of supraglottis:
horizontal plane through the lateral margin of the VENTRICLE at its junction with the SUPERIORsurface of the TRUE VOCAL CORD
Components of the glottis:
True vocal cords
Anterior commissure
Posterior commissure
Inferior boundary of the glottis:
horizontal plane 1 cm inferior to the inferior limit of the supraglottis
(The inferior limit of the supraglottis is defined as the lateral margin of the ventricle at its junction with the superior surface of the vocal cord)
EPITHELIUM.
Supraglottis:
Glottis:
Subglottis:
Supraglottis: pseudostratified columnar (except at edges of the ARYEPIGLOTTIC FOLDS AND LATERAL BORDERS of the EPIGLOTTIS - Stratified Squamous)
Vocal cords: Stratified squamous
Subglottis: pseudostratified columnar
In summary:
Supra and subglottis: pseudostratified columnar
Forms the superior bordered of the conus elasticus:
and this structure is made up of ____ and ___
vocal ligament - made up of intermediate and deep layers of the lamina propria
What anatomical concept explains why the Pre epiglottic space is frequently invaded by tumors?
Fenestrations through the cartilage of the epiglottis.
“frequently invaded by
tumors, because the cartilage of the epiglottis has multiple
small fenestrations through which cancers that arise from the
infrahyoid epiglottis may pass.”
Supraglottic tumors with PES involvement are staged as _____ lesions
T3
Lymphatics of PES (neck node levels)
II and III
“The lymphatics of the PES drain through the
thyrohyoid membrane and spread to lymph nodes on both
sides of the neck, primarily in level II and III”
Boundaries of the paraglottic space:
The PGS lies lateral to the true and false vocal folds and
extends laterally to the thyroid cartilage (Fig. 106-5). The
boundaries of each PGS are medially (from superior to inferior),
the quadrangular membrane, laryngeal ventricle, and conus
elasticus; laterally, the thyroid cartilage anteriorly and the
mucosa of the medial wall of the piriform sinus posteriorly; and
inferolaterally, the cricothyroid membrane.8 Anteriorly, each
PGS is continuous with the PES, and tumors may spread along
this pathway
PGS involvement in either a glottic or supraglottic tumor is staged as:
T3.
PGS involvement in either a
glottic or supraglottic tumor is staged as T3 and is significant
because the extent of the PGS means that tumors in this space
may spread to involve any or all of the three regions of the
larynx
Definition of a transglottic tumor.
as a tumor that crosses the ventricle in a vertical
direction. LeRoux-Robert12 probably first described this type of
cancer, proposing that the site of origin was the ventricle and
that this was the only tumor that invaded supraglottic and subglottic
areas. Kirchner and colleagues11 have shown that transglottic
tumors do not necessarily arise from the ventricle.
“Transglottic tumors are an important subset of laryngeal tumors
with aggressive behavior and high risk of lymphatic metastasis”
Ways by which tumors can become transglottic:
1) by crossing the
ventricle directly
2) by crossing at the anterior commissure
3) by spreading through the paraglottic space
4) by spread
ing
along the arytenoid cartilage posterior to the ventricle
What is the anterior commissure?
What is the anterior commissure tendon?
Why is this insertion important?
The anterior commissure is the part of the glottis where the
true vocal cords meet anteriorly. The anterior commissure
tendon is a 1-mm wide, 10-mm long band of fibrous tissue that
extends from the vocal ligaments to the midline of the inner
surface of the thyroid cartilage.
At this insertion, the thyroid
cartilage is devoid of perichondrium.
Therefore in this area,
the true vocal cords are in close approximation to the thyroid
cartilage.
Pathways of spread. Glottic tumors have access to the following structures superiorly and inferiorly:
SUPERIORLY:
Petiole of the epiglottis
Pre epiglottic space
INFERIORLY:
subglottic lymphatics
thyroid cartilage
cricothyroid membrane
