Laboratory Studies
A white blood cell (WBC) count should be performed to investigate for any evidence of leukocytosis and shift that might indicate a possible infectious process or lymphoproliferative disease.
Imaging Studies
Imaging studies are most helpful in the diagnostic evaluation of salivary gland tumors (SGTs). [2, 11]
Ultrasonography (US) is often the first-line modality for characterizing a neoplasm within the parotid or submandibular glands. In many cases, high-resolution US can adequately assess the size, evaluate the general morphology (cystic, solid, or complex), and define the type of borders (well-circumscribed vs poorly defined), thereby facilitating diagnosis and surgical management. Surgeon-performed US may serve as an extension of the physical examination or may be ordered as a separate standalone study, depending on institutional preferences.
Magnetic resonance imaging (MRI) and computed tomography (CT) may be used to further characterize larger tumors, those that extend beyond the depth that US can adequately assess, and those that raise concerns for malignant features on US or clinical assessment. (See the images below.) MRI is the most sensitive test for establishing the borders of soft-tissue tumor extension and perineural invasion or spread.
Heterogeneous, predominantly low-density mass in tail of right parotid gland with minimal thin peripheral enhancement consistent with Warthin tumor.
Dense, small, solid lesions in parotid glands (more on left side than on right) in patient with lymphoma. This is representative of lymphomatous involvement of glands.
Ill-defined masses in parotid glands bilaterally, proven to be large B-cell lymphoma in this patient with known Sjögren disease.
Bilateral, solid, inhomogeneous parotid gland masses that are larger on left side than on right, with minimal necrosis. These were caused by lymphoma.
In most circumstances, findings from CT and MRI cannot reliably be used to differentiate benign from malignant disease. In a study of 46 major SGTs, Aghaghazvini et al found that dynamic contrast-enhanced MRI had potential utility for differentiating SGTs preoperatively, specifically with regard to distinguishing between Warthin tumors and benign non-Warthin tumors. [12]
Biopsy
In selected cases, fine-needle aspiration (FNA) biopsy (FNAB) may facilitate the management of a mass in the salivary gland by helping to distinguish a tumor from certain nonneoplastic or inflammatory processes that may respond better to medical management.
In most patients who present with a salivary mass, the decision to offer surgical management is likely to be determined by clinical and imaging characteristics, and FNA may be considered as part of the workup on the basis of specific considerations of the case. Most benign tumors and low-grade malignancies without lymphadenopathy are treated by surgical extirpation of the primary tumor alone. Patients with high-grade salivary malignancies may require removal of the primary tumor and lymphadenectomy at the same time.
The reliability of FNA in making the diagnosis and determining the grade of malignancy remains a controversial issue. Additionally, the utility of FNA in distinguishing high-grade malignancies from low-grade malignancies and benign tumors may be limited by the local availability of expertise. In the absence of the ability to differentiate the grade of malignancy, FNA may play a limited role in the decision to offer an operation; however, if the diagnosis of a high-grade salivary gland malignancy is made preoperatively, FNA may influence the extent of the operation. [5, 13]
-
Histology of salivary gland unit.
-
Coronal MRI demonstrating benign tumor of parapharyngeal space.
-
Right submandibular benign salivary gland tumor in 42-year-old woman.
-
Pictures before (above, left) and after (above, right) treatment for benign mandibular gland tumor. Specimen picture of gland (below).
-
Right parotid gland is slightly larger than left; normal variation.
-
Prominent bilateral parotid glands with homogenous parenchyma; normal variation.
-
Normal right submandibular sialogram.
-
Normal CT scan after right submandibular sialogram.
-
Normal CT scan after right submandibular sialogram.
-
In this patient with history of parotitis, note 7-mm lobulated calcification anteriorly within superficial right parotid gland with focally dilated ducts. Dystrophic calcifications due to remote inflammatory disease are also present bilaterally in tonsillar fossa.
-
Note 12-mm right parotid, smoothly marginated, multilobulated, solid lesion, without focal calcification or necrosis. This was proven to be pleomorphic adenoma.
-
Note 2- × 1.5-cm uniformly enhancing, smoothly marginated mass in superficial right parotid gland without necrosis or calcification, which is consistent with epithelial neoplasm such as pleomorphic adenoma.
-
Coronal image of patient with history of parotitis.
-
Heterogeneous, predominantly low-density mass in tail of right parotid gland with minimal thin peripheral enhancement consistent with Warthin tumor.
-
In this patient with infectious sialoadenitis, note inhomogeneous, enlarged left submandibular gland with mild thickening of adjacent platysma.
-
After radiation treatment of right parotid sialoadenitis.
-
After radiation treatment of right sialoadenitis.
-
Nodular and cystic changes in both parotid glands. These changes are stable in this patient with history of chronic sialoadenitis.
-
Dense, small, solid lesions in parotid glands (more on left side than on right) in patient with lymphoma. This is representative of lymphomatous involvement of glands.
-
Ill-defined masses in parotid glands bilaterally, proven to be large B-cell lymphoma in this patient with known Sjögren disease.
-
Large B-cell lymphoma in patient with known Sjögren disease.
-
Large B-cell lymphoma in patient with known Sjögren disease.
-
Bilateral, solid, inhomogeneous parotid gland masses that are larger on left side than on right, with minimal necrosis. These were caused by lymphoma.
-
Facial nerve (white arrow) and its divisions (green arrows) are shown. Retromandibular vein is visible (blue arrow).
-
Parotidectomy. Left parotid mass; preoperative marking of modified Blair incision on skin.
-
Parotidectomy. Wide plane maintaining thick vascularized skin flap is raised anteriorly. Note that greater auricular nerve is preserved, when possible, during this dissection.
-
Parotidectomy. With wide plane of dissection maintained, sternocleidomastoid muscle and posterior belly of digastric muscle are exposed. Main trunk of facial nerve is starting to appear (white arrow).
-
Facial nerves. Note network between zygomatic branch and buccal branch.
-
Facial nerve branches.
-
Exposed facial nerve branches after superficial parotidectomy.
-
Facial nerves. Note variations in nerve sizes and change of takeoff locations of branches.
-
Facial nerves. Note two main trunks, frontozygomatic and cervical-marginal-mandibular.
Tables
Pleomorphic adenoma Warthin tumor Oncocytoma Basal cell adenoma Myoepithelioma Lymphadenoma Cystadenoma Sialadenoma papilliferum Ductal papillomas Sebaceous adenoma Canalicular adenoma and other ductal adenomas |
