Download Major Salivary Glands (Parotid, Submandibular, and Sublingual)

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Major Salivary Glands (Parotid, Submandibular,
and Sublingual)
C07.9
C08.0
C08.1
Parotid gland
Submandibular gland
Sublingual gland
C08.8
Overlapping lesion of
major salivary glands
C08.9
Major salivary gland,
NOS
SUMMARY OF CHANGES
• In order to maintain internal consistency of T staging across all sites, the description for T3 has been revised. In addition to tumors having extraparenchymal
extension, all tumors larger than 4 cm are considered T3.
• T4 lesions have been divided into T4a (resectable) and T4b (unresectable),
leading to the division of Stage IV into Stage IVA, Stage IVB, and Stage IVC.
INTRODUCTION
This staging system is based on an extensive retrospective review of the world
literature regarding malignant tumors of the major salivary glands. Numerous
factors affect patient survival, including the histologic diagnosis, cellular differentiation of the tumor (grade), site, size, degree of fixation or local extension,
facial nerve involvement, and the status of regional lymph nodes as well as
distant metastases. The classification involves the four dominant clinical variables: tumor size, local extension of the tumor, nodal metastasis, and distant
metastasis. The T4 category has been divided into T4a and T4b. T4a indicates
advanced lesions that are resectable with grossly clear margins; T4b reflects
extension to areas that preclude resection with clear margins. Histologic grade,
patient age, and tumor site are important additional factors that should be
recorded for future analysis and potential inclusion in the staging system.
ANATOMY
Primary Site. The major salivary glands include the parotid, submandibular,
and sublingual glands. Tumors arising in minor salivary glands (mucussecreting glands in the lining membrane of the upper aerodigestive tract) are
staged according to the anatomic site of origin (e.g., oral cavity, sinuses, etc.).
Primary tumors of the parotid constitute the largest proportion of salivary
gland tumors. Sublingual primary cancers are rare and may be difficult to distinguish with certainty from minor salivary gland primary tumors of the anterior floor of the mouth.
Regional Lymph Nodes. Regional lymphatic spread from salivary gland
cancer is less common than from head and neck mucosal squamous cancers and
varies according to the histology and size of the primary tumor. Most nodal
metastases will be clinically apparent on initial evaluation.
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Low-grade tumors rarely metastasize to regional nodes, whereas the risk of
regional spread is substantially higher from high-grade cancers. Regional dissemination tends to be orderly, progressing from intraglandular to adjacent
(periparotid, submandibular) nodes, then to upper and midjugular nodes, and
occasionally to retropharyngeal nodes. Bilateral lymphatic spread is rare.
For pN, a selective neck dissection will ordinarily include 6 or more lymph
nodes, and a radical or modified radical neck dissection will ordinarily include
10 or more lymph nodes. Negative pathologic examination of a lesser number
of lymph nodes still mandates a pN0 designation.
Metastatic Sites. Distant spread is most frequently to the lungs.
DEFINITIONS
Primary Tumor (T)
TX Primary tumor cannot be assessed
T0 No evidence of primary tumor
T1 Tumor 2 cm or less in greatest dimension without extraparenchymal
extension(1) (Figure 7.1)
T2 Tumor more than 2 cm but not more than 4 cm in greatest dimension
without extraparenchymal extension(1) (Figure 7.2)
T3 Tumor more than 4 cm and/or tumor having extraparenchymal extension(1) (Figures 7.3A, B)
T4a Tumor invades skin, mandible, ear canal, and/or facial nerve (Figures
7.4A–D)
T1
Lingual nerve
Hypoglossal
nerve
Myelohyoid
muscle
£2 cm
FIGURE 7.1. T1 is defined as a tumor 2 cm or less in greatest dimension without
extraparenchymal extension (a coronal section thru the floor of the mouth with
tumor of the submandibular gland is shown).
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FIGURE 7.2. T2 is defined as
a tumor greater than 2 cm
but not more than 4 cm in
greatest dimension without
extraparenchymal extension
(an axial section with tumor of
the deep lobe of the parotid
gland is shown).
T2
Mastoid
process
Facial nerve
Isthmus of
parotid gland
2-4 cm
Facial
nerve
Masseter
muscle
T3
7
>4 cm
A
T3
Medial pterygoid
muscle
Masseter muscle
Tumor
Parotid gland
B
FIGURE 7.3. A. T3 is defined as greater than 4 cm and/or tumor having
extraparenchymal extension (a tumor of the superficial lobe of the parotid gland is
shown). B. Cross-sectional diagram of T3 tumor with extraparenchymal extension
from the parotid gland.
T4a
Facial nerve
A
T4a
Mandible
Masseter muscle
Medial pterygoid
muscle
Skin
Parotid gland
B
T4a
T4a
Mandible
Medial
pterygoid
muscle
C
Masseter muscle
Skin
Ear canal
D
FIGURE 7.4. A. T4a is defined as tumor invading skin, mandible, ear canal, and/or
facial nerve (as illustrated here). B. Cross-sectional diagram of T4a tumor invading
skin. C. Cross-sectional diagram of T4a tumor invading mandible. D. Coronal
section of T4 tumor invading ear canal.
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T4b
Carotid
artery
T4b
Skull
base
A
B
FIGURE 7.5. A. T4b is defined as tumor invading skull base and/or pterygoid
plates and/or encasing carotid artery. In this cross-sectional diagram, the
tumor encases the carotid artery. B. Coronal section of T4b tumor invading skull
base.
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T4b Tumor invades skull base and/or pterygoid plates and/or encases carotid
artery (Figures 7.5A, B)
Regional Lymph Nodes (N) (see Figure 2.4)
NX Regional lymph nodes cannot be assessed
N0 No regional lymph node metastasis
N1 Metastasis in a single ipsilateral lymph node, 3 cm or less in greatest
dimension
N2 Metastasis in a single ipsilateral lymph node, more than 3 cm but not more
than 6 cm in greatest dimension, or in multiple ipsilateral lymph nodes,
none more than 6 cm in greatest dimension, or in bilateral or contralateral lymph nodes, none more than 6 cm in greatest dimension
N2a Metastasis in a single ipsilateral lymph node, more than 3 cm but not more
than 6 cm in greatest dimension
N2b Metastasis in multiple ipsilateral lymph nodes, none more than 6 cm in
greatest dimension
N2c Metastasis in bilateral or contralateral lymph nodes, none more than 6 cm
in greatest dimension
N3 Metastasis in a lymph node, more than 6 cm in greatest dimension
Distant Metastasis (M)
MX Distant metastasis cannot be assessed
M0 No distant metastasis
M1 Distant metastasis
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STAGE GROUPING
I
II
III
IVA
IVB
IVC
T1
T2
T3
T1
T2
T3
T4a
T4a
T1
T2
T3
T4a
T4b
Any T
Any T
N0
N0
N0
N1
N1
N1
N0
N1
N2
N2
N2
N2
Any N
N3
Any N
M0
M0
M0
M0
M0
M0
M0
M0
M0
M0
M0
M0
M0
M0
M1
NOTE
1. Extraparenchymal extension is clinical or macroscopic evidence of invasion of soft
tissues. Microscopic evidence alone does not constitute extraparenchymal extension for classification purposes.
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