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

In order to establish whether the lump is a cyst or not, several imaging tests may be performed. Mammography is usually the first imaging test to be ordered when unusual breast changes have been detected during a physical examination. A diagnostic mammography consists in a series of x-rays that provide clear images of specific areas of the breast.

Ultrasounds and MRIs are commonly performed in conjunction with mammographies as they produce clear images of the breast and clearly distinguish between fluid-filled breast cysts and solid masses. The ultrasound and MRI exams can better evaluate dense tissue of the breast; hence it is often undergone by young patients, under 30 years old.

The breast biopsy is usually the test used to confirm the suspected diagnosing. After imaging tests have been performed and have revealed unusual areas or lumps in the breast, a breast biopsy will be ordered. This test consists in removing a sample of breast tissue which is then looked at under a microscope. The specialist analyzing the tissue sample will be able to conclude if the breast changes are benign or malignant or whether breast fibrocystic disease is present.

There are four main types of breast biopsies that may be performed. A fine-needle aspiration biopsy is usually ordered when the doctor is almost certain that the lump is a cyst. This test is generally performed in conjunction with an ultrasound which is helpful in guiding the needle into a small or hard to find lump. The procedure is painless and it consists in inserting a thin needle into the breast tissue while the lump is palpated.

The core-needle biopsy is normally performed under local anesthesia and in a physician's office. The needle used in this procedure is slightly larger than the one used for a fine-needle biopsy because the procedure is intended to remove a small cylinder of tissue that will be sent to the laboratory for further examination.

A newer type of breast biopsy is the stereotactic biopsy that relies on a three-dimensional x-ray to guide the needle biopsy of non-palpable mass. The biopsy is performed in a similar manner, by using a needle to remove tissue sample but locating the specific area of the breast is done by x-raying the breast by two different angles. Surgical biopsy is a procedure performed to remove the entire lump or a part of it for laboratory analyzing. It may be painful and it is done under local anesthesia.

Most of the time, nipple problems are not breast cancer. These problems will either go away with the right treatment, or they can be watched closely over time.

Recommended tests are a mammogram and a biopsy to confirm the diagnosis, and cytopathology may also be helpful. Paget's disease is difficult to diagnose due to its resemblance to dermatitis and eczema; even in patients after ductal carcinoma in situ surgery. Eczema tends to affect the areola first, and then the nipple, whereas Paget's spreads from the nipple.

During a physical examination, the doctor examines the unusual areas of the breast, especially the appearance of the skin on and around the nipples and feeling for any lumps or areas of thickening.

The most common test used to diagnose Paget's disease is the biopsy, removal of a tissue sample from the affected area which is then examined under the microscope by a pathologist, who distinguishes Paget cells from other cell types by staining tissues to identify specific cells (immunohistochemistry). Samples of nipple discharge may also be examined under the microscope to determine whether Paget cells are present.

Imprint or scrape cytopathology may be useful: scraping cells from the affected area, or pressing them onto a glass slide to be examined under the microscope.

On average, a woman may experience signs and symptoms for six to eight months before a diagnosis is made.

Lesions of the nipple and areola, such as nipple adenoma, may be difficult to image clearly on routine mammogram or ultrasonography. Nipple adenomas can be imaged using magnetic resonance imaging (MRI) and conventional or MR ductogram.

The cystic nature of a breast lump can be confirmed by ultrasound examination, aspiration (removal of contents with needle), or mammogram. Ultrasound can also show if the cyst contains solid nodules, a sign that the lesion may be pre-cancerous or cancerous. Examination by a cytopathologist of the fluid aspirated from the cyst may also help with this diagnosis. In particular, it should be sent to a laboratory for testing if it is blood-stained.

Commonly, cysts are detected with the help of mammograms. However, the medical history and physical examination also play an important role in establishing an accurate diagnosis. During these tests, the doctor will try to find out as much information as possible regarding the symptoms the patient has experienced, their intensity and duration and the physical examination is performed regularly to check for other abnormalities that may exist within the breast.

As mentioned above, cysts are often undetectable at touch. Therefore, a mammogram can provide valuable and clear images of the breast tissue. Generally, if there is any abnormality within the breast tissue, it will be shown on the mammogram. There are two types of mammograms available. One of them is primarily used in screening, and are ordered for patients who do not show any symptoms and these are called screening mammograms. Diagnostic mammograms are used on patients who developed certain symptoms of a breast condition or in patients whose screening mammograms showed abnormalities.

Patients suspected of breast cysts will normally be given a diagnosing mammogram, although they are not suspected of cancer. This type of mammogram provides the doctor with the possibility of performing a breast ultrasound at the same time and this is the reason why they are often preferred over the screening mammograms. Breast ultrasound is considered the best option when diagnosing breast cysts because it is 95 to 100% accurate, it provides a clear image on the cyst's appearance (simple or complex) and it may also distinguish between solid lumps and fluid-filled cysts, which a mammogram cannot do. Breast ultrasounds are performed with the help of a handheld medical instrument which is placed on the skin, after a special type of fluid has been applied on it. The instruments picks up the echo resulted from the sound waves it sends to the breast. These echoes are transmitted to a computer which translates it into a picture.

Breast cysts may remain stable for many years or may resolve spontaneously. Most simple cysts are benign and do not require any treatment or further diagnostic workup. Some complex cysts may require further diagnostic measures such as fine needle aspiration or biopsy to exclude breast cancer however the overwhelming majority is of benign nature. Aspiration both diagnoses and removes cysts at the same time. That is, cysts will usually resolve on their own after the fluid is drained. Otherwise, if the lump is not a cyst, the fluid aspirated may contain blood or there may not be fluid at all. Whereas in the first case, the fluid is sent to the laboratory for further examination, the latter circumstance is a sign that the breast lump is solid. This type of tumor needs to be biopsied in order to determine whether it is malignant or benign.

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.

The presence of a radial scar on imaging mandates a percutaneous core biopsy for histologic diagnosis. Excisional biopsy is usually recommended for radial scar, although it has been argued that core biopsy evaluation and surveillance may be appropriate in selected patients.

The appropriate treatment in contemporary western medicine is complete surgical excision of the abnormal growth with a small amount of normal surrounding breast tissue.

A fibroadenoma is usually diagnosed through clinical examination, ultrasound or mammography, and often a needle biopsy sample of the lump.

"Duct ectasia" in the literal sense (literally: duct widening) is a very common and thus rather unspecific finding, increasing with age. However, in the way in which the term is mostly used, duct ectasia is an inflammatory condition of the larger-order lactiferous ducts. It considered likely that the condition is associated with aseptic (chemical) inflammation related to the rupture of ducts or cysts. It is controversial whether duct dilation occurs first and leads to secretory stasis and subsequent periductal inflammation or whether inflammation occurs first and leads to an inflammatory weakening of the duct walls and then stasis. When the inflammation is complicated by necrosis and secondary bacterial infection, breast abscesses may form. Subareolar abscess, also called Zuska's disease (only nonpuerperal case), is a frequently aseptic inflammation and has been associated with squamous metaplasia of the lactiferous ducts.

The duct ectasia—periductal mastitis complex affects two groups of women: young women (in their late teens and early 20s) and perimenopausal women. Women in the younger group mostly have inverted nipples due to squamous metaplasia that lines the ducts more extensively compared to other women and produces keratin plugs which in turn lead to duct obstruction and then duct dilation, secretory stasis, inflammation, infection and abscess. This is not typically the case for women in the older group; in this group, there is likely a multifactorial etiology involving the balance in estrogen, progesterone and prolactin.

Treatment of mastitis and/or abscess in nonlactating women largely the same as that of lactational mastitis, generally involving antibiotics treatment, possibly surgical intervention by means of fine-needle aspiration and/or incision and drainage and/or interventions on the lactiferous ducts (for details, "see also" the articles on treatment of mastitis, of breast abscess and of subareolar abscess). Additionally, an investigation for possible malignancy is needed, normally by means of mammography, and a pathological investigation such as a biopsy may be necessary to exclude malignant mastitis. Although no "causal" relation with breast cancer has been established, there appears to be an increased statistical risk of breast cancer, warranting a long-term surveillance of patients diagnosed with non-puerperal mastitis.

Nonpuerperal breast abscesses have a higher rate of recurrence compared to puerperal breast abscesses. There is a high statistical correlation of nonpuerperal breast abscess with diabetes mellitus (DM). On this basis, it has recently been suggested that diabetes screening should be performed on patients with such abscess.

Most recently the fourteenth Congress of the International Association of Pancreatology developed the International Consensus Diagnostic Criteria (ICDC) for AIP. The ICDC emphasizes five cardinal features of AIP which includes the imaging appearance of pancreatic parenchyma and the pancreatic duct, serum IgG4 level, other organ involvement with IgG4-related disease, pancreatic histology and response to steroid therapy.

In 2002, the Japanese Pancreas Society proposed the following diagnostic criteria for autoimmune pancreatitis:

For diagnosis, criterion I (pancreatic imaging) must be present with criterion II (laboratory data) and/or III (histopathologic findings).

Mayo Clinic has come up with five diagnostic criteria called HISORt criteria which stands for histology, imaging, serology, other organ involvement, and response to steroid therapy.

Most polyps are benign and do not need to be removed. Polyps larger than 1 cm with co-occurring gallstones occurring in people over the age of 50 may have the gallbladder removed (cholecystectomy), especially if the polyps are several or appear malignant. Laparoscopic surgery is an option for small or solitary polyps.

The diagnosis of mastitis and breast abscess can usually be made based on a physical examination. The doctor will also take into account the signs and symptoms of the condition.

However, if the doctor is not sure whether the mass is an abscess or a tumor, a breast ultrasound may be performed. The ultrasound provides a clear image of the breast tissue and may be helpful in distinguishing between simple mastitis and abscess or in diagnosing an abscess deep in the breast. The test consists of placing an ultrasound probe over the breast.

In cases of infectious mastitis, cultures may be needed in order to determine what type of organism is causing the infection. Cultures are helpful in deciding the specific type of antibiotics that will be used in curing the disease. These cultures may be taken either from the breast milk or of the material aspirated from an abscess.

Mammograms or breast biopsies are normally performed on women who do not respond to treatment or on non-breastfeeding women. This type of tests is sometimes ordered to exclude the possibility of a rare type of breast cancer which causes symptoms similar to those of mastitis.

Polypoid lesions of the gallbladder affect approximately 5% of the adult population. The causes are uncertain, but there is a definite correlation with increasing age and the presence of gallstones (cholelithiasis). Most affected individuals do not have symptoms. The gallbladder polyps are detected during abdominal ultrasonography performed for other reasons.

The incidence of gallbladder polyps is higher among men than women. The overall prevalence among men of Chinese ancestry is 9.5%, higher than other ethnic types.

The presence of three factors for the prognosis has been suggested, whether there is a palpable mass of the disease, whether lymph nodes are positive and whether there is an underlying malignant cancer.

If there is none of these, the five- and 10-year survival is 85% and 80% respectively, with adjuvant chemotherapy even 95% and 90%. If there is a palpable mass, it is 32% and 31% respectively, with adjuvant chemotherapy (40% and 35%).

Positive lymph-nodes have been positively associated with a palpable mass and affect the prognosis to be now just 28% survival after 10 years (vs 79% without palpable mass and without affected lymph-nodes). Involvement of the lymph nodes does not directly cause any harm, but is merely an indicator of systemic spread.

Furthermore, patients with an identifiable associated underlying breast tumor have a survival rate of 38-40% at five years and a survival rate of 22-33% at 10 years. The death rate of metastatic breast carcinoma in patients with mammary Paget's disease and underlying cancer is 61.3%, with a 10-year cumulative survival rate of 33%.

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.

The only reliable method of diagnosis is full-thickness skin biopsy. Mammography, MRI or ultrasound often show suspicious signs; however in a significant proportion of cases they would miss a diagnosis.

Clinical presentation is typical only in 50-75% of cases; and many other conditions such as mastitis or even heart insufficiency can mimic the typical symptoms of Inflammatory Breast Cancer.

Temporary regression or fluctuation of symptoms, spontaneous or in response to conventional treatment or hormonal events should not be considered of any significance in diagnosis. Treatment with antibiotics or progesterone have been observed to cause a temporary regression of symptoms in some cases.

Colposcopically, it presents itself similarly to columnar epithelium on the cervix, assisted with lugol's solution application for diagnosis. It can be discovered as nodules or cysts on the vaginal tube, with biopsy needed for further diagnosis. As seen cytologically, epithelial and stromal cells in vaginal adenosis show characteristic fusion through the basal lamina or with stromal fibroblasts. Adenosal cells can be distinguished as mucinous, tuboendometrial, and embryonic. Its mucinous cells resemble the normal cervical lining, while its tuboendometrial cells resemble the lining of normal fallopian tubes or endometrium.

It is sometimes considered a precancerous lesion, given clear-cell adenocarcinoma patients present these lesions in close proximity to atypical tuboendometrial glands, and microglandular hyperplasia has been seen to arise from these lesions.

Comedo mastitis is a very rare form similar to granulomatous mastitis but with tissue necrosis. Because it is so rare it may be sometimes confused with comedo carcinoma of the breast although the conditions appear to be completely unrelated.

Breast diseases can be classified either with disorders of the integument, or disorders of the reproductive system. A majority of breast diseases are noncancerous.

Fibrosclerosis of the breast is most frequently used to mean sclerosing lobular adenosis of the breast. It is not well known if it is related to non-sclerosing adenosis of the breast (which is normally classified as fibrocystic breast changes) and unlike this it is believed to be correlated with an elevated risk of breast cancer.

In regards to the diagnosis of idiopathic sclerosing mesenteritis, a CT scan which creates cross-section pictures of the affected individuals body, can help in the assessment of the condition.

The FDA has approved cryoablation of a fibroadenoma as a safe, effective and minimally-invasive alternative to open surgical removal in 2001. In the procedure, ultrasound imaging is used to guide a probe into the mass of breast tissue. Extremely cold temperatures are then used to destroy the abnormal cells, and over time the cells are reabsorbed into the body. The procedure can be performed as an outpatient surgery using local anesthesia only, and leaves substantially less scarring than open surgical procedures and no breast tissue deformation.

The American Society of Breast Surgeons recommends the following criteria to establish a patient as a candidate for cryoablation of a fibroadenoma:

1. The lesion must be sonographically visible.

2. The diagnosis of a fibroadenoma must be confirmed histologically.

3. The lesion should be less than 4 cm in diameter.