SALIVARY GLANDS
THYROID
DIFFUSE THYROID DISEASE
THYROID NODULE & CANCER
HIGH SUSPICION
Microcalcifications
Hypoechogenicity w irregular margins
Taller-than-wide shape
INTERMEDIATE SUSPICION
Hypoechogenicity with regular margins
LOW/VERY LOW SUSPICION
Hyperechoic/isoechoic solid nodules w regular margins
Spongiform echotexture
Partially cystic nodules with eccentric solid mass.
PARATHYROID
SALIVARY GLANDS
Major salivary glands are in order of decreasing size, the parotid, submandibular, and sublingual glands.
Numerous unnamed minor salivary glands throughout the mucosa of the H&N, especially palate.
Neoplasms in smaller glands are more likely to be malignant, with the risk highest in sublingual and minor salivary glands, followed by the submandibular gland, and least in the parotid gland.
PAROTID GLANDS
The parotid glands are divided by the facial nerve into superficial and deep lobes.
The facial nerve is not normally visible on imaging so radiologists use the retromandibular vein as the demarcation.
Deep lobe extends through the stylomandibular tunnel into the prestyloid parapharyngeal space.
Parotid tail: inferior projection of the superficial lobe overlying the angle of the mandible.
Parotid glands are only salivary glands to contain internal LNs, mostly located in the superficial lobe along the retromandibular vein.
Accessory parotid glands may be located along the parotid duct (stensen duct) superficial to masseter mm.
SUBMANDIBULAR GLANDS
SUBLINGUAL GLAND
PALANTINE TONSILS
SCC of the palatine tonsil should be specifically sought when necrotic/cystic mets are discovered in level II.
Extranodal lymphoma can involve either lingual lymphoid tissue or palatine tonsils and may have associated bulky cervical adenopathy. LNs usually NOT necrotic.
Minor salivary gland tumors are smooth, enhancing submucosal lesions with minimal enhancement. The lymphadenopathy in this case would not be explained by a benign mixed tumor.
BENIGN SALIVARY NEOPLASM
PLEOMORPHIC ADENOMA
AKA benign mixed tumor; MC salivary gland tumor accounting for 70% of all salivary tumors and is most commonly in the parotid gland.
Typical patient is a middle-aged female
Composed of a mixture of variable histology containing both epithelial and myoepithelial tissues. They appear encapsulated and well-circumscribed however the pseudocapsule is delicate and incomplete w microscopic extensions reaching beyond it, accounting for the high risk of recurrence when they tumors are enucleated.
Location:
84% parotid gland, MC in superficial lobe
8% submandibular gland
6.5% minor salivary glands (nasal cavity, pharynx, larynx, trachea)
Also found in lacrimal glands where they account for approximately 50% of lacrimal gland tumors.
IMAGING
CT:
When small, have homogeneous attenuation and prominent enhancement.
When larger, they can be heterogeneous w/ less prominent enhancement, foci of necrosis and possible delayed enhancement. Small regions of calcification are common.
MRI:
Well-defined mass w bosselated margins (small undulations)
Very high T2 signal
Strong contrast enhancement; usually homogeneous
Large pleomorphic adenomas can have heterogenous signal
DSA: hypovascular
US: hypoechoic
Although benign, there is a risk of malignant transformation. Thus, standard tx is superficial parotidectomy.
Carcinoma ex-pleomorphic adenoma: proportional to the time the lesion is in situe (1.5% in first 5 years, 9.5% after 15 years). RF for transformation are advanced age, large size, radiation therapy, recurrent tumors.
