Salivary gland neoplasms most commonly appear in the sixth decade of life.
Patients with malignant lesions typically present after age 60 years, whereas those with benign lesions usually present when older than 40 years.
Benign neoplasms occur more frequently in women than in men, but malignant tumors are distributed equally between the sexes.
In children, 35% of salivary gland neoplasms are malignant. Hemangiomas are the most common benign tumor.
larger gland tumours are most common and most are benign tumours
Nearly 80% of these tumors occur in the parotid glands, 15% in the submandibular glands and the remaining 5% in the sublingual and minor salivary glands.
Benign neoplasms make up about 80% of parotid tumors, 50% of submandibular tumors and 10% of sublingual and 50% of minor salivary gland tumors.
palate is the most common site of minor salivary gland tumors
Most common benign major and minor salivary gland tumor is the pleomorphic adenoma, which comprises about 50% of all salivary gland tumors and 65% of parotid gland tumors
most common malignant parotid tumors in adults
mucoepidermoid carcinoma (10% of all salivary gland neoplasms)
adenoid cystic carcinoma
malignant mixed tumor.
most common malignant parotid tumors in children:
acinic cell carcinoma
exposure to low dose ionizing radiation
occupational exposure to rubber products manufacturing, asbestos mining, plumbing, and some types of woodworking
smoking associated with Warthins tumor
2 predominant theories:
Bicellular stem cell theory
This theory holds that tumors arise from 1 of 2 undifferentiated stem cells, the excretory duct reserve cell or the intercalated duct reserve cell.
Excretory stem cells give rise to squamous cell and mucoepidermoid carcinomas
Intercalated stem cells give rise to pleomorphic adenomas, oncocytomas, adenoid cystic carcinomas, adenocarcinomas, and acinic cell carcinomas.
each tumor type is associated with a specific differentiated cell of origin within the salivary gland unit.
Squamous cell carcinomas arise from excretory duct cells, oncocytomas arise from the striated duct cells, pleomorphic adenomas arise from the intercalated duct cells ,and acinic cell carcinomas originate from acinar cells.
Recent evidence suggests that the bicellular stem cell theory is the more probable etiology of salivary gland neoplasms. This theory more logically explains neoplasms that contain multiple discrete cell types, such as pleomorphic adenomas and Warthin tumors.
• pain - assoc with eating usually stone disease
• mass 81%
• pain 12%
• facial nerve paralysis 7%
• 50% Sx > 1yr
• oral cavity and oropharynx
• Warthin and Stensons ducts and orifices (flow, clarity, consistency, purulence, redness, bulging and irritation of the duct
• Tonsillar fossa and soft palate
• Bimanual palpation of all glands
• Comparison between sides
• Examination of neck
• Examination for other primaries that may have metastasized to the glands
N1: Metastasis in a single ipsilateral lymph node, ≤3 cm in greatest dimension
N2: Metastasis in a single ipsilateral lymph node, >3 cm but ≤6 cm in greatest dimension, or in multiple ipsilateral lymph nodes, ≤6 cm in greatest dimension, or in bilateral or contralateral lymph nodes, ≤6 cm in greatest dimension
N2a: Metastasis in a single ipsilateral lymph node >3 cm but ≤6 cm in greatest dimension
N2b: Metastasis in multiple ipsilateral lymph nodes, ≤6 cm in greatest dimension
N2c: Metastasis in bilateral or contralateral lymph nodes, ≤6 cm in greatest dimension
N3: Metastasis in a lymph node >6 cm in greatest dimension
Distant metastasis (M)
MX: Distant metastasis cannot be assessed
M0: No distant metastasis
M1: Distant metastasis
AJCC stage groupings
T1, N0, M0
T2, N0, M0
T3, N0, M0
T1, N1, M0
T2, N1, M0
T3, N1, M0
T4a, N0, M0
T4a, N1, M0
T1, N2, M0
T2, N2, M0
T3, N2, M0
T4a, N2, M0
T4b, any N, M0
Any T, N3, M0
Any T, any N, M1
MANAGEMENT OF BENIGN TUMOURS
superficial parotidectomy for tumours of the superficial lobe
25% extend to or involve the deep lobe - total parotidectomy with preservation of the nerve is indicated
Postoperative radiation therapy should be considered when the resection margins are positive.
High-grade tumors Localized high-grade salivary gland tumors that are confined to the gland in which they arise may be cured by radical surgery alone.
Postoperative radiation therapy may improve local control and increase survival rates for patients with high-grade tumors, positive surgical margins, or perineural invasion
Stage II/III Major Salivary Gland Cancer Low-grade tumors
Surgery alone or with postoperative radiation therapy, if indicated.
Chemotherapy should be considered in special circumstances, such as when radiation therapy or surgery are refused.
Localized high-grade salivary gland tumors that are confined to the gland in which they arise may be cured by radical surgery alone.
Postoperative radiation therapy may improve local control and increase survival rates for patients with high-grade tumors, positive surgical margins, or perineural invasion.[Level of evidence: 3iii]
Fast neutron-beam radiation or accelerated hyperfractionated photon beam schedules reportedly are more effective than conventional x-ray therapy in the treatment of inoperable, unresectable, or recurrent malignant salivary gland tumors.
Stage IV Major Salivary Gland Cancer/ Recurrent cancer Not curable with surgery
Fast neutron-beam radiation or accelerated hyperfractionated photon beam schedules have been reported to be more effective than conventional x-ray therapy in the treatment of inoperable, unresectable, or recurrent malignant salivary gland tumors
bacterial infections are usually associated with ductal obstruction
most common bacterial pathogens are staph. aureus, strep viridans, B-haemolytic strep and pneumococcus
may develop submandibular abscess, spread to involve other deep neck spaces of the neck. Trismus may be indicative of parapharyngeal involvement.
Viral infections less common - coxsackievirus, parainfluenza, cytomegalovirus, echovirus, HIV
Mumps can affect one or both parotids and the other salivary glands
recurrent attacks cause atrophy, fibrosis, strictures
typically less painful and is associated with recurrent enlargement of the gland (often following meals) typically without erythema.
Associated with conditions linked to decreased salivary flow, rather than dehydration
These conditions include calculi, salivary stasis, and a change in the fluid and electrolyte composition of the gland.
80% submandibular and are usually radioopaque
20% parotid and radiolucent
present with a colicky postprandial swelling of the gland
typically composed of calcium phosphate or calcium carbonate
mechanism of stone formation:
Epithelial injury along the duct resulting in sialolith formation, which acts as a nidus for further stone formation
Precipitation of calcium salts
absence of the parotid and facial n in 1st and 2nd branchial arch syndromes
herterotopic salivary gland tissue and sinuses
pseudocysts resulting from ductal rupture and localized extravasation of minor salivary glands
may also occur due to partial or total excretory duct obstruction leading to acinar rupture due to intraluminal hypertension
Ranulas (Rana = frog belly), which involve the major salivary glands, are divided into 2 types
Oral ranulas - secondary to mucus extravasation that pools superior to the mylohyoid muscle - large unilateral blue to translucent mass in the floor of the mouth
Cervical ranulas (deep plunging) are associated with mucus extravasation along the fascial planes of the neck – almost always due to ranula of the sublingual gland
Histologically, ranulas lack an epithelial lining and instead are lined by a condensed fibrous connective tissue wall that is infiltrated by inflammatory cells
CT - mucus content is homogeneous and its density, as seen on a CT scan, is much less than surrounding muscle tissue. Also diagnostic tail that can be used to trace it from the sublingual gland in the sublingual space to the submandibular space.
Differentials include: cystic hygroma, thyroglossal or branchial cleft cysts.
Oral and cervical ranulas require complete excision of the oral portion of the ranula, in addition to the responsible gland. Usually, the sublingual gland is the origin of the ranula; however, occasionally, the submandibular gland may be the source