Review of the Major and Minor Salivary Glands, Part 2: Neoplasms and Tumor-like Lesions

Abstract

The salivary glands are small structures in the head and neck, but can give rise to a wide variety of benign and malignant pathology. When this occurs, patients may present with palpable swelling, although it is quite common that they are asymptomatic and a salivary gland mass was discovered as an incidental finding on imaging performed for another reason. It is, therefore, critical that radiologists pay careful attention to the salivary glands and have working knowledge of the key differentiating features of the most common neoplastic and nonneoplastic etiologies of salivary gland masses. The purpose of this review is to provide a succinct image-rich article illustrating the various causes of salivary gland masses via an extensive review of the primary literature. In Part 2, we discuss neoplasms and tumor-like lesions of the salivary glands with a key emphasis on specific imaging features of the most common pathologic entities.

Keywords: Ranula; salivary gland neoplasms; salivary glands; vascular malformations.

Figure 1

Pleomorphic adenoma. Axial T2-weighted (a) and axial apparent diffusion coefficient (b) Magnetic resonance images demonstrate a well-circumscribed high signal lesion in the deep portion of the right parotid gland (white arrows). Note that the lesion demonstrates T2 hyperintensity greater than nearby cerebrospinal fluid.

Figure 2

Carcinoma ex pleomorphic adenoma. (a) Axial computed tomography image demonstrates a well-circumscribed mass spanning the superficial and deep portions of the right parotid gland (red arrow), nonspecific in etiology. (b) Axial computed tomography image performed 4 months later demonstrates rapid enlargement with infiltrative margins (blue arrow). (c) Axial computed tomography image at a slightly lower level demonstrates new right level II lymph nodes (yellow arrows). Pathologically confirmed carcinoma ex pleomorphic adenoma with metastatic lymphadenopathy.

Figure 3

Warthin's Tumor. A 94-year-old male with right neck swelling. Coronal contrast-enhanced computed tomography images demonstrate multifocal enhancing masses in the right parotid gland (white arrows), pathologically proven Warthin's Tumor.

Figure 4

Mucoepidermoid Carcinoma. A 53-year-old male with right neck pain and palpable lump. Axial contrast-enhanced computed tomography image demonstrates an enhancing mass with ill-defined margins and central cystic component (white arrow).

Figure 5

Adenoid cystic carcinoma, sinonasal minor salivary gland origin. (a) Axial T1-weighted postcontrast fat-suppressed magnetic resonance image demonstrates a heterogeneous mass in the right maxillary sinus (white arrow). Posteriorly, there is osseous invasion through the wall of the maxillary sinus into the retroantral fat (red arrow). Axial T1-weighted postcontrast fat-suppressed magnetic resonance image (b) and axial computed tomography image (c) demonstrate asymmetric widening and enhancement in the pterygopalatine fossa (yellow arrow) and vidian canal (green arrow), consistent with perineural spread of tumor.

Figure 6

Adenoid cystic carcinoma, nasopharynx minor salivary gland origin. (a) Axial T1-weighted postcontrast fat-suppressed magnetic resonance image demonstrates a large heterogeneous mass centered in the nasopharynx (white arrow). Coronal T1-weighted postcontrast fat-suppressed magnetic resonance image (b) and coronal computed tomography image (c) demonstrate associated destruction of the central skull base with perineural extension through left foramen ovale (blue arrows).

Figure 7

Acinic cell carcinoma. A 51-year-old female with enlarging palpable right parotid mass over 3 months. Axial contrast-enhanced computed tomography (a) and transverse FDG-PET (b) images demonstrate a hypermetabolic ill-defined mass within the lower right parotid gland, extending toward the tail (white arrows). At a slightly lower level, axial contrast-enhanced computed tomography (c) and transverse FDG-PET (d) images demonstrate enlarged hypermetabolic right level II lymph nodes (red arrows). Pathologically proven acinic cell carcinoma with metastatic lymphadenopathy.

Figure 8

Oncocytoma. (a) Axial T2-weighted fat-suppressed image demonstrates a barely perceptible mass in the deep portion of the parotid gland (white arrow), isointense to normal parotid parenchyma. (b) Axial T1-weighted postcontrast fat-suppressed image also demonstrates a subtle mass isointense to normal parotid parenchyma (white arrow). (c) Transverse fused PET/computed tomography image demonstrates an obvious hypermetabolic mass (white arrow). Pathologically proven oncocytoma.

Figure 9

Lipoma. An 81-year-old female presents with dysarthria and aphasia. Axial computed tomography image demonstrates an incidental mass in the left parotid gland with attenuation characteristics equal to fat (white arrow). Findings compatible with a parotid gland lipoma.

Figure 10

Intraparotid Metastases. A 90-year-old male with a history of left temple cutaneous squamous cell carcinoma presents with the left cheek swelling. Axial computed tomography (a) and fused PET/computed tomography (b) images demonstrate two hypermetabolic necrotic lymph nodes in the left parotid tail (white arrows). Biopsy-proven metastatic squamous cell carcinoma.

Figure 11

Hemangioma. A 1-month-old infant with left neck mass. Axial T2-weighted image (a) and axial T1-weighted postcontrast fat-suppressed (b) images demonstrate a lobulated mass in the left parotid gland with T2 hyperintensity and homogeneous enhancement, compatible with an infantile hemangioma.

Figure 12

Simple ranula. A 7-year-old male with swelling along the left floor of mouth. Axial T2 fat-suppressed image demonstrates a cystic lesion occupying the entire left sublingual space. Note there is no extension beyond the mylohyoid sling into the submandibular space.

Figure 13

Plunging ranula. A 15-year-old male with swelling along the left floor of the mouth. Axial (a) and sagittal (b) T2-weighted fat-suppressed images demonstrate a cystic lesion occupying the entire sublingual space with extension beyond the posterior margin of the mylohyoid sling (white arrow) into the submandibular space. Note narrower “tail” (yellow arrow) in the portion left behind in the sublingual space.

Figure 14

Vascular malformation. A 49-year-old male with a history of “vascular lesion since birth,” although no prior imaging was available. Axial T2-weighted fat-suppressed image demonstrates a transspatial lesion involving the left parotid space, masticator space, oral tongue, and paraspinal soft tissues. Hemorrhage-fluid levels are present within many portions of the lesion (white arrow), compatible with a lymphatic malformation.