Diagnosis is usually made by characteristic history and physical examination. Diagnosis can be confirmed by x-ray (80% of salivary gland calculi are visible on x-ray), by sialogram, or by ultrasound.

Dacryoadenitis can be diagnosed by examination of the eyes and lids. Special tests such as a CT scan may be required to search for the cause. Sometimes biopsy will be needed to be sure that a tumor of the lacrimal gland is not present.

Standard, and most effective, therapy to date is glandular sialadenectomy, which is associated with fairly low operative morbidity; however, in recent times, the administration of steroid (which can shrink the inflammatory lesion and is known to reduce serum IgG4 values) has been considered favorably, and may be useful in younger patients or those who refuse surgery.

Mumps can be prevented by immunization. Gonococcus, bacteria can be avoided by the use of condoms. Most other causes cannot be prevented.

Treatment usually consists of observation unless the patient has concern, there is pain, drainage, or other symptoms related to the lesion. Surgical removal of the affected gland would be recommended in those cases. Another treatment option would be aspiration, which can be repeated multiple times. This is commonly performed in those who are debilitated or in those whose benefit from surgery would be outweighed by the risks. Prognosis is usually good; rarely this condition may devolve into lymphoma, or could actually represent 'occult' lymphoma from the outset.

A salivary diverticulum (plural "diverticuli") is a small pouch or out-pocketing of the duct system of a major salivary gland. Such diverticuli typically cause pooling of saliva and recurrent sialadenitis, especially parotitis. A diverticulum may also cause a sialolith to form.

The condition can be diagnosed by sialography. Affected individuals may "milk" the salivary gland to encourage flow of saliva through the duct.

No treatment is required, but neoplastic processes (metastatic maliganancy to the submandibular lymph nodes and/or salivary gland tumours) should be ruled out. This is usually done with clinical exam and imaging. Very rarely, since the defect contains salivary gland tissue, salivary gland tumors can occur within an established defect but there is likely no difference in the risk of neoplasia in salivary gland tissue at other sites.

Some current treatment options are:

- Non-invasive:

- For small stones, hydration, moist heat therapy, NSAIDs (nonsteroidal anti-inflammatory drugs) occasionally, and having the patient take any food or beverage that is bitter and/or sour. Sucking on citrus fruits, such as a lemon or orange, may increase salivation and promote spontaneous expulsion of the stone.

- Some stones may be massaged out by a specialist.

- Shock wave therapy (Extracorporeal shock wave lithotripsy).

- Minimally invasive:

- Sialendoscopy

- Surgical:

- An ENT or oral/maxillofacial surgeon may cannulate the duct to remove the stone (sialectomy).

- A surgeon may make a small incision near the stone to remove it.

- In some cases when stones continually reoccur the offending salivary duct is removed.

- Supporting treatment:

- To prevent infection while the stone is lodged in the duct, antibiotics are sometimes used.

Given the difficulties of a definitive pre-operative diagnosis, the clinical entity of Küttner's tumor has so far remained significantly under-reported and under-recognized. In recent times, armed with a better understanding of the occurrences and observable features of this condition, surgeons are increasingly depending upon pre-operative ultrasonography along with Fine-needle aspiration cytological (FNAC) examinations to make an accurate presumptive diagnosis, and according to one estimate, about 44% of patients undergoing submandibular resection are found to have this condition. In the ultrasonogram, Küttner's tumor is characterized by a diffuse, heterogeneous zone of echo-shadows. The FNAC finds cells greatly reduced in number (called 'paucicellularity') along with scattered tubular ducts against a backdrop of lymphoplasmacytic infiltration and fibrous depositions. There may be a reduced but moderate number of cells and ducts enveloped in fibrous sheaths, as well as fibrous proliferation of the gland's septa. The cytologic findings by themselves may not be specific, and the diagnosis requires adjunct consideration of both the ultrasonogram and clinical presentation. Application of magnetic resonance imaging (MRI) has been tried to non-invasively examine the morphological variations in Küttner's tumor and differentiate them from those seen in malignant tumors; while MRI findings of the affected tissue and the pattern of cellular infiltration may offer some diagnostic clues for this condition, so far the results have been inconclusive.

Blockage of the main parotid duct, or one of its branches, is often a primary cause of acute parotitis, with further inflammation secondary to bacterial superinfection. The blockage may be from a salivary stone, a mucous plug, or, more rarely, by a tumor, usually benign. Salivary stones (also called sialolithiasis, or salivary duct calculus) are mainly made of calcium, but do not indicate any kind of calcium disorder. Stones may be diagnosed via X-ray (with a success rate of about 80%), a computed tomography (CT) scan or Medical ultrasonography. Stones may be removed by manipulation in the doctor's office, or, in the worst cases, by surgery. Lithotripsy, also known as "shock wave" treatment, is best known for its use breaking up kidney stones. Lithotripsy can now be used on salivary stones as well. Ultrasound waves break up the stones, and the fragments flush out of the salivary duct.

The histologic appearance is similar to mucoceles from other locations. The spilled mucin causes a granulation tissue to form, which usually contains foamy histiocytes. Ultrasound and magnetic resonance imaging may be useful to image the lesion. A small squamous cell carcinoma obstructing the Wharton duct may require clinical examination to be distinguished from a ranula.

Mainly, the diagnosis of hypophysitis is through exclusion – patients often undergo surgery because they are suspected of having a pituitary adenoma. But, the most accurate diagnosis is using Magnetic Resonance Imaging (MRI) to find any mass or lesions on the Sella Turcica.

There are many diagnostic methods that can be used to determine the type of salivary gland tumour and if it is benign or malignant. Examples of diagnostic methods include:

Physical exam and history: An exam of the body to check general signs of health. The head, neck, mouth, and throat will be checked for signs of disease, such as lumps or anything else that seems unusual. A history of the patient's health habits and past illnesses and treatments will also be taken.

Endoscopy: A procedure to look at organs and tissues inside the body to check for abnormal areas. For salivary gland cancer, an endoscope is inserted into the mouth to look at the mouth, throat, and larynx. An endoscope is a thin, tube-like instrument with a light and a lens for viewing.

MRI

Biopsy: The removal of cells or tissues so they can be viewed under a microscope by a pathologist to check for signs of cancer.

Fine needle aspiration (FNA) biopsy: The removal of tissue or fluid using a thin needle. An FNA is the most common type of biopsy used for salivary gland cancer, and has been shown to produce accurate results when differentiating between benign and malignant tumours.

Radiographs: An OPG (orthopantomogram) can be taken to rule out mandibular involvement. A chest radiograph may also be taken to rule out any secondary tumours.

Ultrasound: Ultrasound can be used to initially assess a tumour that is located superficially in either the submandibular or parotid gland. It can distinguish an intrinsic from an extrinsic neoplasm. Ultrasonic images of malignant tumours include ill defined margins.

Ectopic salivary gland tissue which is located in sites other than the normal location is variously described as aberrant, accessory, ectopic, heterotopic or salivary gland choristoma.

Stafne's defect is usually discovered by chance during routine dental radiography. Radiographically, it is a well-circumscribed, monolocular, round, radiolucent defect, 1–3 cm in size, usually between the inferior alveolar nerve (IAN) and the inferior border of the posterior mandible between the molars and the angle of the jaw. It is one of the few radiolucent lesions that can occur below the IAN. The border is well corticated and it will have no effect on the surrounding structures. Computed tomography (CT) will show a shallow defect through the medial cortex of the mandible with a corticated rim and no soft tissue abnormalities, with the exception of a portion of the submandibular gland. Neoplasms, such as metastatic squamous cell carcinoma to the submandibular lymph nodes or a salivary gland tumour, could create a similar appearance but rarely have such well defined borders and can usually be palpated in the floor of the mouth or submandibular triangle of the neck as a hard mass. CT and clinical exam is typically sufficient to distinguish between this and a Stafne defect. The Stafne defect also tends to not increase in size or change in radiographic appearance over time (hence the term "static bone cyst"), and this can be used to help confirm the diagnosis. Tissue biopsy is not usually indicated, but if carried out, the histopathologic appearance is usually normal salivary gland tissue. Sometimes attempted biopsy of Stafne defects reveals an empty cavity (possibly because the gland was displaced at the time of biopsy), or other contents such as blood vessels, fat, lymphoid or connective tissues. Defects of the anterior lingual mandible may require biopsy for correct diagnosis at this unusual location. The radiolucent defect here may be superimposed on the lower anterior teeth and be mistaken for an odontogenic lesion. Sometimes the defect may interrupt the contour of the lower border of the mandible, and may be palpable. Sialography may be sometimes used to help demonstrate the salivary gland tissue within the bone.

There is a marked lymphoplasmacytic infiltration. Lymphoid follicles surround solid epithelial nests, giving rise to the 'epimyoepithelial islands', that are mainly composed of ductal cells with occasional myoepithelial cells. Excess hyaline basement membrane material is deposited between cells, and there is also acinar atrophy and destruction.

The lesion is usually present in children. Ranulas are the most common pathologic lesion associated with the sublingual glands.

Biopsy is the only means of accurate diagnosis as no autoantigen has been discovered. Biopsy of the pituitary gland is not easily performed with safety as it sits under the brain, however, a test does exist to detect antibodies to the pituitary without biopsy: autoantibodies to M(r) 49,000 pituitary cytosolic protein may represent markers for an immunological process affecting the pituitary gland. Tests for normal pituitary gland hormone production tend to be expensive and in some cases difficult to administer. In addition, certain hormone levels vary largely throughout the day and in response to metabolic factors, making abnormal levels difficult to calibrate—further hampering diagnosis.

Sclerosing polycystic adenosis is a rare, reactive inflammatory condition of the salivary glands. It may be mistaken for salivary gland neoplasia. It does not seem to be a fatal disease.

An "accessory salivary gland" is ectopic salivary gland tissue with a salivary gland duct system. The most common location of accessory salivary gland tissue is an extra major salivary gland in front of the parotid gland. It is typically about 3 cm or less in size, and drains into the parotid duct via a single tributary. Accessory parotid tissue is found in 21-56% of adults. Any disease process which affects the salivary glands, including cancer, may also occur within an accessory salivary gland tissue.

Infections involving the salivary glands can be viral or bacterial (or rarely fungal).

- Mumps is the most common viral sialadenitis. It usually occurs in children, and there is preauricular pain (pain felt in front of the ear), swelling of the parotid, fever, chills, and headaches.

- Bacterial sialadentitis is usually caused by ascending organisms from the oral cavity. Risk factors include reduced salivary flow rate.

- Human immunodeficiency virus-associated salivary gland disease (HIV-SGD).

The prognosis for hypophysitis was variable for each individual. The depending factors for hypophysitis included the advancement of the mass on the Sella Turcica, percentage of fibrosis, and the body's response to corticosteroids. Through the use of Corticosteroids, the vision defects tend to recover when the gland size began to decrease. The prognoses of the limited number of reported cases were usually good.

The most common and helpful way to diagnose thyroiditis is first for a physician to palpate the thyroid gland during a physical examination. Laboratory tests allow doctors to evaluate the patient for elevated erythrocyte sedimentation rates, elevated thyroglobulin levels, and depressed radioactive iodine uptake (Mather, 2007). Blood tests also help to determine the kind of thyroiditis and to see how much thyroid stimulating hormone the pituitary gland is producing and what antibodies are present in the body. In some cases a biopsy may be needed to find out what is attacking the thyroid.

It is important to include that the lesion is associated with another cancer. A biopsy will establish the diagnosis. The histology of the lesion is the same as for Paget's disease of the breast.

Autoantibodies to the thyroid gland may be detected in various disease states. There are several anti-thyroid antibodies, including anti-thyroglobulin antibodies (TgAb), anti-microsomal/anti-thyroid peroxidase antibodies (TPOAb), and TSH receptor antibodies (TSHRAb).

- Elevated anti-thryoglobulin (TgAb) and anti-thyroid peroxidase antibodies (TPOAb) can be found in patients with Hashimoto's thyroiditis, the most common autoimmune type of hypothyroidism. TPOAb levels have also been found to be elevated in patients who present with subclinical hypothyroidism (where TSH is elevated, but free T4 is normal), and can help predict progression to overt hypothyroidism. The American Association Thyroid Association thus recommends measuring TPOAb levels when evaluating subclinical hypothyroidism or when trying to identify whether nodular thyroid disease is due to autoimmune thyroid disease.

- When the etiology of hyperthyroidism is not clear after initial clinical and biochemical evaluation, measurement of TSH receptor antibodies (TSHRAb) can help make the diagnosis. In Grave's disease, TSHRAb levels are elevated as they are responsible for activating the TSH receptor and causing increased thyroid hormone production.