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.

Multiple imaging modalities may be necessary to evaluate abnormalities of the nipple-areolar complex.

In two studies performed in Japan, high-resolution MRI with a microscopy coil yielding 0.137-mm in-plane resolution has been used to confirm the presence of abscesses, isolated fistulas and inflammation and to reveal their position in order to guide surgery.

Evaluation is in the form of a dye disappearance test followed by irrigation test. By using this sequence (with modifications) as a guide, the physician can frequently streamline diagnostic testing.

In irrigation test, a lacrimal irrigation cannula is passed into the punctum and advanced through the canaliculus to the lacrimal fossa. Clear water or saline is then irrigated through the cannula. If fluid passes into the nose without reflux out of the opposite canaliculus, the system is patent. If no fluid passes but it all comes back through either punctum, nasolacrimal duct obstruction is present.

Ultrasound is the often chosen to examine the duct and determine the presence and size of any cysts or abnormalities. Fine-needle aspiration cytology can also be used to confirm the diagnosis.

The condition is usually self-limiting, and thus not indicated for surgery.

In one report, about 20% of individuals with mealtime syndrome had strictures upon sialography. For unknown reasons, strictures seem to be more common in females.

The term "duct ectasia syndrome" has been used to describe symptoms of nonpuerperal mastitis, possibly associated with nipple inversion and nipple discharge. In some contexts, it was used to describe a particular form of nonpuerperal mastitis coincident with fibrocystic disease, frequently involving pasty (coloured) nipple discharge, nipple retraction, retroareolar abscess and blue dome cysts. Abscessation is not very frequent but by some definitions recurrent subareolar abscess is merely a variant of duct ectasia syndrome - abscessation would be obviously more frequent with this definition.

Duct ectasia syndrome has been associated with histopathological findings that are distinct from a simple duct widening. In addition to nonspecific duct widening the myoepithelial cell layer is atrophic, missing or replaced by fibrous tissue. The original cuboidal epithelial layer may be also severely impaired or missing. Characteristic calcifications are often visible on mammographic images.

Periductal mastitis, comedo mastitis, secretory disease of the breast, plasma cell mastitis and mastitis obliterans are sometimes considered special cases or synonyms of duct ectasia syndrome.

Strictures tend to be diagnosed based on difficulty with insertion and manipulation during sialendoscopy, or by sialography or ultrasound.

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.

Treatment is problematic unless an underlying endocrine disorder can be successfully diagnosed and treated.

A study by Goepel and Panhke provided indications that the inflammation should be controlled by bromocriptine even in absence of hyperprolactinemia.

Antibiotic treatment is given in case of acute inflammation. However, this alone is rarely effective, and the treatment of a subareaolar abscess is primarily surgical. In case of an acute abscess, incision and drainage are performed, followed by antibiotics treatment. However, in contrast to peripheral breast abscess which often resolves after antibiotics and incision and drainage, subareaolar breast abscess has a tendency to recur, often accompanied by the formation of fistulas leading from inflammation area to the skin surface. In many cases, in particular in patients with recurrent subareolar abscess, the excision of the affected lactiferous ducts is indicated, together with the excision of any chronic abscess or fistula. This can be performed using radial or circumareolar incision.

There is no universal agreement on what should be the standard way of treating the condition. In a recent review article, antibiotics treatment, ultrasound evaluation and, if fluid is present, ultrasound-guided fine needle aspiration of the abscess with an 18 gauge needle, under saline lavage until clear, has been suggested as initial line of treatment for breast abscess in puerperal and non-puerperal cases including central (subareolar) abscess (see breast abscess for details). Elsewhere, it has been stated that treatment of subareolar abscess is unlikely to work if it does not address the ducts as such.

Duct resection has been traditionally used to treat the condition; the original Hadfield procedure has been improved many times but long term success rate remains poor even for radical surgery. Petersen even suggests that damage caused by previous surgery is a frequent cause of subareolar abscesses. Goepel and Pahnke and other authors recommend performing surgeries only with concomitant bromocriptine treatment.

Imaging by ultrasonography, MRCP, or CT scan usually make the diagnosis. MRCP can be used to define the lesion anatomically prior to surgery.

Occasionally Mirizzi's syndrome is diagnosed or confirmed on ERCP when requested to alleviate obstructive jaundice or cholangitis by means of an endoscopically placed stent, or when USS has been wrongly reported as choledocolithiasis.

The most common and accurate way of diagnosing an individual with this anomaly is by MRCP (Magnetic Resonance Cholangiopancreatography) or ERCP (Endoscopic Retrograde Cholangiopancreatography). This test can demonstrate the presence of two separately draining ducts within the pancreas. Other tests can assist doctors with diagnosis, such as a CT scan and an MRI.

In order to prevent further cysts and infections from forming, the thyroglossal duct and all of its branches are removed from the throat and neck area. A procedure, known as the Sistrunk procedure, is considered to be the standard procedure and involves removal of portions of the hyoid bone and core tissue of the suprahyoid region. Cysts will often reoccur if the entire duct is not removed, so reoccurrence requires a wider range of tissue to be removed in a subsequent surgery.

Delaying the surgical procedure almost always leads to recurrent infections, which will continue to delay the needed treatment. The Sistrunk procedure has a reoccurrence rate of less than 5%, proving it is extremely effective at removing the majority of traces of the persistent thyroglossal duct.

Pleural or ascitic fluid should be sent for analysis. An elevated amylase level, usually > 1,000 IU/L, with protein levels over 3.0 g/dL is diagnostic. Serum amylase is often elevated as well, due to enzyme diffusion across the peritoneal or pleural surface. Contrast-enhanced computed tomography and endoscopic retrograde cholangiopancreatography (ERCP) may also assist in diagnosis, with the latter an essential component of treatment.

A salivary gland fistula (plural "fistulae") is a fistula (i.e. an abnormal, epithelial-lined tract) involving a salivary gland or duct.

Salivary gland fistulae are almost always related to the parotid gland or duct, although the submandibular gland is rarely the origin.

The fistula can communicate with the mouth (usually causing no symptoms), the paranasal sinuses (giving rhinorrhea) or the facial skin (causing saliva to drain onto the skin).

The usual cause is trauma, however salivary fistula can occur as a complication of surgery, or if the duct becomes obstructed with a calculus.

Most parotid fistulae heal by themselves within a few weeks.

Other conditions that may present similarly include hidradenoma papilliferum, lipomas, epidermoid cysts and Skene's duct cysts among others. In those who are more than 40 years of age a biopsy may be recommended to ensure cancer is not present.

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.

The diagnosis of nipple discharge will be determined upon an examination by a health provider who will ask questions about symptoms and medical history. Tests that may be done include:

- Prolactin blood test

- Thyroid blood tests

- Head CT scan or MRI to look for pituitary tumor

- Mammography

- Ultrasound of the breast

- Breast biopsy

- Ductography or ductogram: an x-ray with contrast dye injected into the affected milk duct

- Skin biopsy, if Paget disease is a concern

Salivary gland atresia is congenital blockage or absence of the orifice of a major salivary gland duct or part of the duct itself.

It is a very rare condition. The submandibular salivary gland duct is usually involved, having failed to cannulate during embryological development. The condition first becomes apparent in the first few days after birth where a submandibular swelling caused by a retention cyst is noticed.

Computed tomography (CT) findings in AIP include a "diffusely enlarged hypodense" pancreas or a focal mass that may be mistaken for a pancreatic malignancy. A low-density, "capsule-like rim on CT" (possibly corresponding to an inflammatory process involving peripancreatic tissues) is thought to be an additional characteristic feature (thus the mnemonic: "sausage-shaped"). Magnetic resonance imaging (MRI) reveals a diffusely decreased signal intensity and delayed enhancement on dynamic scanning. The characteristic ERCP finding is segmental or diffuse irregular narrowing of the main pancreatic duct, usually accompanied by an extrinsic-appearing stricture of the distal bile duct. Changes in the extrapancreatic bile duct similar to those of primary sclerosing cholangitis (PSC) have been reported.

The role of endoscopic ultrasound (EUS) and EUS-guided fine-needle aspiration (EUS-FNA) in the diagnosis of AIP is not well described, and EUS findings have been described in only a small number of patients. In one study, EUS revealed a diffusely swollen and hypoechoic pancreas in 8 of the 14 (57%) patients, and a solitary, focal, irregular mass was observed in 6 (46%) patients. Whereas EUS-FNA is sensitive and specific for the diagnosis of pancreatic malignancy, its role in the diagnosis of AIP remains unclear.

Simple cholecystectomy is suitable for type I patients. For types II–IV, subtotal cholecystectomy can be performed to avoid damage to the main bile ducts. Cholecystectomy and bilioenteric anastomosis may be required. Roux-en-Y hepaticojejunostomy has shown good outcome in some studies.

Nasopalatine duct cysts usually present as asymptomatic palatal swellings, but they may rarely be accompanied by pain and/or purulent discharge. The cysts are generally treated by .

The clinical management of a cyst of Montgomery depends upon the symptoms of the patient.

If there are no signs of infection, a cyst of Montgomery can be observed, because more than 80% resolve spontaneously, over only a few months. However, in some cases, spontaneous resolution may take up two years. In such cases, a repeat ultrasonography may become necessary. If, however, the patient has signs of an infection, for example reddening (erythema), warmth, pain and tenderness, a treatment for mastitis can be initiated, which may include antibiotics and non-steroidal anti-inflammatory drugs (NSAIDs). With treatment, inflammatory changes usually disappear quickly. In rare cases, drainage may become necessary. A surgical treatment of a cyst of Montgomery, i.e. a resection, may become necessary only if a cyst of Montgomery persists, or the diagnosis is questioned clinically.

The prognosis seems to be excellent. In one series, all adolescent patients with a cyst of Montgomery had a favourable outcome.

Choledocholithiasis (stones in common bile duct) is one of the complications of cholelithiasis (gallstones), so the initial step is to confirm the diagnosis of cholelithiasis. Patients with cholelithiasis typically present with pain in the right-upper quadrant of the abdomen with the associated symptoms of nausea and vomiting, especially after a fatty meal. The physician can confirm the diagnosis of cholelithiasis with an abdominal ultrasound that shows the ultrasonic shadows of the stones in the gallbladder.

The diagnosis of choledocholithiasis is suggested when the liver function blood test shows an elevation in bilirubin and serum transaminases. Other indicators include raised indicators of ampulla of vater (pancreatic duct obstruction) such as lipases and amylases. In prolonged cases the INR may change due to a decrease in vitamin K absorption. (It is the decreased bile flow which reduces fat breakdown and therefore absorption of fat soluble vitamins).

The diagnosis is confirmed with either an MRCP (magnetic resonance cholangiopancreatography), an ERCP, or an intraoperative cholangiogram. If the patient must have the gallbladder removed for gallstones, the surgeon may choose to proceed with the surgery, and obtain a cholangiogram during the surgery. If the cholangiogram shows a stone in the bile duct, the surgeon may attempt to treat the problem by flushing the stone into the intestine or retrieve the stone back through the cystic duct.

On a different pathway, the physician may choose to proceed with ERCP before surgery. The benefit of ERCP is that it can be utilized not just to diagnose, but also to treat the problem. During ERCP the endoscopist may surgically widen the opening into the bile duct and remove the stone through that opening. ERCP, however, is an invasive procedure and has its own potential complications. Thus, if the suspicion is low, the physician may choose to confirm the diagnosis with MRCP, a non-invasive imaging technique, before proceeding with ERCP or surgery.