Radiation Oncology and Salivary Gland Tumor Anatomy Quiz

The major salivary glands are parotid, submandibular, and sublingual glands located in the mouth and neck region responsible for saliva production and secretion.

The sublingual gland is a major salivary gland located underneath the tongue and next to the genioglossus muscle.

The parotid gland is the largest of the salivary glands and is located posterior to the masseter muscle. It is reached by the posterior ramus of the mandible and has Stenson's duct as its main duct. The sublingual gland is located under the tongue, the submandibular gland is beneath the mandible, and the minor salivary glands are scattered throughout the oral cavity, making them incorrect choices for this question.

Salivary gland tumors are most commonly found in the parotid gland, followed by the submandibular gland, minor glands, and rarely in the sublingual gland. The percentages vary, but the general distribution remains consistent across various studies.

The correct rule of thumb is that smaller salivary glands have a higher probability of containing malignant tumors. This is important to keep in mind when assessing the likelihood of malignancy in different locations within the salivary glands.

Salivary gland tumors account for a relatively small percentage of Head and Neck cancers, with an incidence rate of 1-3 cases per 100,000 per year.

Salivary gland tumors show a mean age of 55 for malignant tumors and 45 for benign tumors. Both men and women are affected equally in the distribution of these tumors.

Salivary gland tumors may exhibit either local/regional spread or distant spread at an approximately equal frequency. Both types of spread can occur depending on various factors.

The correct risk of developing diabetes mellitus in patients with salivary gland tumors of adenoid cystic histology is 50%, while for minor salivary glands it is 25%. This risk varies based on the histology of the tumor and the specific salivary gland involved.

The correct answer is that the risk of lymph node involvement is 60% in cases of salivary gland tumors with facial nerve paralysis or tumors larger than 4cm. This indicates a moderate likelihood of lymph node involvement in such cases.

The prognostic factors for salivary gland tumors include grade, size, and local invasion as they impact the outcome and treatment approach.

Salivary gland tumors are not associated with smoking or alcohol use. While genetic factors may play a role in some cases, radiation exposure, Epstein-Barr virus (EBV), possible vitamin deficiencies, and UV radiation are some of the known risk factors for salivary gland tumors.

Parotid tumors are more commonly benign than malignant, with only a small percentage being malignant. The major subtypes of parotid tumors include pleiomorphic adenoma, mucoepidermoid, adenoid cystic, and acinic tumors.

Parotid tumors predominantly arise from the superficial lobe, with approximately 90% of cases originating in this lobe. This distinction is important for diagnostic and treatment purposes.

Salivary gland tumors can have various histologic subtypes, but mucoepidermoid carcinoma and adenoid cystic carcinoma are the most common ones based on their respective percentage of occurrence.

Fine needle aspiration (FNA) has a sensitivity ranging from 87-94% and a specificity ranging from 75-100% in detecting malignant cells in salivary gland tumors. This makes FNA a valuable tool in the diagnostic process for these tumors.

The correct indications for radiation therapy in salivary gland tumors include specific criteria such as tumor grade, extent of resection, involvement of surrounding tissues, and lymph node status. It is not a blanket recommendation for all cases or limited to only advanced stages or specific histological types.

In 2002 AJCC staging, T1 refers to tumors that are 2 cm or less in size. Therefore, any other size measurements would be considered incorrect for this staging.

In the 2002 AJCC staging system, T2 corresponds to a tumor size of 2-4cm based on the classification criteria.

In the AJCC staging system for major salivary gland tumors, T3 indicates a tumor size greater than 4cm and/or presence of extraparenchymal extension. Therefore, options 1, 2, and 3 are incorrect as they do not meet the criteria for T3 staging.

T4a staging indicates the invasion of skin, mandible, ear canal, and/or facial nerve by the Major Salivary gland tumors, distinguishing it from lower stages which may not involve such structures.

Major Salivary gland tumors classified under 2002 AJCC staging 4b refers to an advanced stage where the tumor invades critical structures such as the skull base, pterygoid plates, or encases the carotid artery. Understanding the extent of invasion helps in determining the stage of the tumor and guides treatment decisions.

The 2002 AJCC staging N1 criteria for major salivary gland tumors is defined as same as H&N-mets in single ipsi LN, 3 cm or less, meaning involvement of a single ipsilateral lymph node with a size of 3 cm or less.

In the 2002 AJCC staging for Major Salivary gland tumors, N2a refers to the presence of a single ipsilateral node with a size range of 3-6 cm. Therefore, options like Bilateral nodes, Multiple ipsilateral nodes, and Contralateral node do not align with the correct staging criteria for N2a.

The correct answer indicates that the staging for Major Salivary gland tumors is the same as Head and Neck (H&N) with multiple ipsilateral lymph nodes involved, none of which are greater than 6 cm in size.

In the 2002 AJCC staging for major salivary gland tumors, the N2c stage corresponds to involvement of the same level as the head and neck-bilateral contralateral lymph nodes, with none being more than 6 cm in size. Therefore, options stating involvement of unilateral lymph nodes or those exceeding 6 cm would be incorrect.

In the 2002 AJCC staging system for Major Salivary gland tumors, the designation N3 is used when the lymph node (LN) involved is greater than 6cm in size.

In the 2002 AJCC staging system, Stage I major salivary gland tumors are classified as T1N0M0. This means the primary tumor size is T1 with no regional lymph node involvement (N0) and no distant metastasis (M0).