The Neck: The Salivary Glands

10.1055/b-0034-87905

The Neck: The Salivary Glands

**Table 4.50 Unilateral masses**
Diagnosis	Findings	Comments
Pleiomorphic adenoma	US: solid, well-defined, homogeneous, hypoechoic mass ± echogenic foci, with calcification. CT: If small, well-marginated homogeneously enhancing ovoid mass. If large, enhances inhomogeneously with foci necrosis/hemorrhage ± calcification. MRI: depending on size, homogeneous or heterogenous low signal on T1 and high signal on T2 with mild to moderate enhancement. NM: cold lesion.	Third most common benign salivary gland tumor in children. Sixty to ninety percent occur in parotid gland. Hard painless mass.
Hemangioma Fig. 4.166	US: focal/diffuse, heterogenous, hypoechoic soft-tissue mass with prominent vascular flow. CT/MRI with contrast: diffuse CE of well-defined mass.	Most common benign tumor of salivary gland in children. Capillary/cavernous/hemangioendothelioma. Identify shortly after birth with rapid growth then slow spontaneous involution.
Lymphangioma	US: cystic mass with thin septa ± solid elements; ± fluid-fluid levels; ± vascularization in septa or solid portions. CT: Low-density, poorly circumscribed cystic mass that may be unior multilocular, ± fluid-fluid levels. No enhancement. MRI: T1 hypoisointense, T2 hyperintense, no CE (unless mixed vascular component).	Second most common salivary gland tumor in children. Involve adjacent structures commonly (i.e., trans-spatial). Sixty-five percent present at birth.
Warthin tumor (papillary cystadenoma lymphomatosum)	US: well-defined, hypoechoic, cystic mass or masses. CT: Solitary well-circumscribed ovoid mass with poor enhancement. Thirty percent have cystic component. No calcification. MRI: solid/cystic lesions with minimal enhancement. NM: hot lesion.	Occurs only in parotid gland: superficial lobe. Twenty percent are multiple lesions. Ten percent are bilateral. Most common multifocal salivary tumor.
Mucoepidermoid carcinoma Fig. 4.167	US: unifocal, heterogenous, ill-defined margins. CT: enhancing inhomogenous mass. MRI: heterogenous signal and heterogenous enhancement.	Sixty percent of malignant salivary tumors are mucoepidermoid or acinic cell carcinoma. Majority arise in parotids. Associated with rapid growth, facial nerve paralysis, and lymphadenopathy Low-grade: well-defined. High-grade: ill-defined shaggy margins, invasive.
Rhabdomyosarcoma	Extension into glands from other sites.	(see Tables 4.39 and 4.49 )
Sialectasis Fig. 4.168 Fig. 4.169	US: calculi are echogenic foci with posterior shadowing. ± ductal dilatation, ± inflammation. Sialogram: punctuate dilatation of the salivary ducts. T2 MRI: foci of high signal intensity throughout the gland.	Ninety percent involve submandibular gland. Majority of calculi are radiopaque and may be ductal/intraglandular.
Abscess (Staphylococcus aureus) Fig. 4.170	US: well-defined hypoechoic mass with surrounding edema/induration. CECT: rim-enhancing, thick-walled cystic mass. MRI: rim enhancement of abscess, high signal on T2.	Local tenderness and fever.
Ranula Fig. 4.159, p. 392	US: cystic mass in floor or mouth, ± echoes and septa. CT: thin-walled unilocular hypodense lesion with thin enhancing wall. MRI: low signal on T1 and high signal on T2 with wall enhancement.	Specific type of mucocele that originates in the sublingual gland—may be simple (i.e., within gland and lined by epithelium or diving ranula when simple cyst becomes large and ruptures into submandibular space creating a pseudocyst).

**Fig. 4.166** Bilateral large hyperintense parotid masses with flow voids are consistent with bilateral **parotid hemangiomas** on this T2 coronal fat-saturated MRI of the face and neck.

**Fig. 4.167** T1 coronal fat-saturated MRI of the parotid glands shows a well-defined, hyperintense left parotid mass; it was proven by histology to be **mucoepidermoid carcinoma**.

**Fig. 4.168** Sialogram of submandibular gland shows multiple dilated salivary ducts, which is consistent with **sialectasis**.

**Fig. 4.169 Sialectasis** with radiopaque calculi in submandibular gland on an oblique radiograph of the mandible.

**Fig. 4.170 Submandibular abscess** with left hypointense rim enhancing on T1 axial fat-saturated postcontrast MRI. Note the surrounding soft-tissue swelling and enhancement.

**Table 4.51 Bilateral masses**
Diagnosis	Findings	Comments
Infection: mumps, parotitis, MOTTS, tuberculosis, cat scratch (Bartonella)	US: enlarged, hypoechoic, heterogenous glands, ± hypoechoic collections, indicating abscess formation. CT: hyperdense glands with mild enhancement MRI: T2—diffuse high signal ± areas focal high signal. T1 with contrast—moderate enhancement, enlarged gland.	Viral parotitis is a clinical diagnosis. Suppurative parotitis often bilateral in neonates.
Human immunodeficiency virus lymphoproliferative disorder Fig. 4.171	US: multiple hypo-/anechoic cysts with thin septa in gland. CT: Thin rim-enhancement of cystic lesions; heterogenous enhancement of solid lesions. MRI: T1—low signal intensity cysts with thin rim enhancement. T2—multiple high signal intensity round lesions.	Multiple solid and cystic lesions within enlarged glands. Often associated cervical adenopathy and tonsillar hyperplasia.
Sjögren’s disease	US: enlarged heterogenous glands with multiple hypoechoic areas, ± small echogenic foci that represent mucous plugs in dilated ducts/walls of ducts. CT: enlarged hyperdense and heterogenous glands, ± calcification with heterogenous enhancement, solid and mixed solid-cystic components. T2 MRI: High signal intensity cystic foci. Size depends on stage. Heterogenous CE.	Chronic inflammation and destruction of gland. Increased risk of developing lymphoma in gland. Juvenile type < 20-y-old men, may resolve spontaneously at puberty.