80% of cases in the United States are diagnosed by mammography screening.

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.

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.

ADH, if found on a surgical (excisional) biopsy of a mammographic abnormality, does not require any further treatment, only mammographic follow-up.

If ADH is found on a core (needle) biopsy (a procedure which generally does not excise a suspicious mammographic abnormality), a surgical biopsy, i.e. a breast lumpectomy, to completely excise the abnormality and exclude breast cancer is the typical recommendation.

Breast cancer screening refers to testing otherwise-healthy women for breast cancer in an attempt to achieve an earlier diagnosis under the assumption that early detection will improve outcomes. A number of screening tests have been employed including clinical and self breast exams, mammography, genetic screening, ultrasound, and magnetic resonance imaging.

A clinical or self breast exam involves feeling the breast for lumps or other abnormalities. Clinical breast exams are performed by health care providers, while self-breast exams are performed by the person themselves. Evidence does not support the effectiveness of either type of breast exam, as by the time a lump is large enough to be found it is likely to have been growing for several years and thus soon be large enough to be found without an exam. Mammographic screening for breast cancer uses X-rays to examine the breast for any uncharacteristic masses or lumps. During a screening, the breast is compressed and a technician takes photos from multiple angles. A general mammogram takes photos of the entire breast, while a diagnostic mammogram focuses on a specific lump or area of concern.

A number of national bodies recommend breast cancer screening. For the average woman, the U.S. Preventive Services Task Force recommends mammography every two years in women between the ages of 50 and 74, the Council of Europe recommends mammography between 50 and 69 with most programs using a 2-year frequency, and in Canada screening is recommended between the ages of 50 and 74 at a frequency of 2 to 3 years. These task force reports point out that in addition to unnecessary surgery and anxiety, the risks of more frequent mammograms include a small but significant increase in breast cancer induced by radiation.

The Cochrane collaboration (2013) states that the best quality evidence neither demonstrates a reduction in cancer specific, nor a reduction in all cause mortality from screening mammography. When less rigorous trials are added to the analysis there is a reduction in mortality due to breast cancer of 0.05% (a decrease of 1 in 2000 deaths from breast cancer over 10 years or a relative decrease of 15% from breast cancer). Screening over 10 years results in a 30% increase in rates of over-diagnosis and over-treatment (3 to 14 per 1000) and more than half will have at least one falsely positive test. This has resulted in the view that it is not clear whether mammography screening does more good or harm. Cochrane states that, due to recent improvements in breast cancer treatment, and the risks of false positives from breast cancer screening leading to unnecessary treatment, "it therefore no longer seems beneficial to attend for breast cancer screening" at any age. Whether MRI as a screening method has greater harms or benefits when compared to standard mammography is not known.

The first step to diagnosing tonsil carcinoma is to obtain an accurate history from the patient. The physician will also examine the patient for any indicative physical signs. A few tests then, maybe conducted depending on the progress of the disease or if the doctor feels the need for. The tests include:

Fine needle aspiration, blood tests, MRI, x-rays and PET scan.

While the histopathologic features and molecular features of ADH are that of (low-grade) DCIS, its clinical behaviour, unlike low-grade DCIS, is substantially better; thus, the more aggressive treatment for DCIS is not justified. In oncology in general, it is observed that tumour size is often strongly predictive of the clinical behaviour and, thus, a number of cancers (e.g. adenocarcinoma of the lung, papillary renal cell carcinoma) are defined, in part, on the basis of a minimum size.

Depending on several factors and the location of the infection, CIN can start in any of the three stage, and can either progress, or regress. The grade of squamous intraepithelial lesion can vary.

CIN is classified in grades:

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

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.

The basis of deciding the T stage depends on physical examination and imaging of the tumor.

Treatment for CIN 1, which is mild dysplasia, is not recommended if it lasts fewer than 2 years. Usually when a biopsy detects CIN 1 the woman has an HPV infection which may clear on its own within 12 months, and thus it is instead followed for later testing rather than treated.

Treatment for higher grade CIN involves removal or destruction of the neoplastic cervical cells by cryocautery, electrocautery, laser cautery, loop electrical excision procedure (LEEP), or cervical conization. Therapeutic vaccines are currently undergoing clinical trials. The lifetime recurrence rate of CIN is about 20%, but it isn't clear what proportion of these cases are new infections rather than recurrences of the original infection.

Surgical treatment of CIN lesions is associated with an increased risk of infertility or subfertility, with an odds ratio of approximately 2 according to a case-control study.

The treatment of CIN during pregnancy increases the risk of premature birth.

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

Vaccinating girls with HPV vaccine before their initial sexual contact has been claimed to reduce incidence of VIN.

Note: differentiation is done accurately by microscopic examination only.

Radial scars are diagnosed by a microscopic examination of excised tissue, i.e. they are diagnosed by pathologists based on their histomorphology.

Because DCIS is normally found early and it is treated or managed, it is difficult to say what occurs if left untreated. About 2% of women who are diagnosed with this condition and treated died within 10 years. Biomarkers can identify which women who were initially diagnosed with DCIS are at high or low risk of subsequent invasive cancer.

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.

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.

Diagnosis is mostly done based on symptoms after exclusion of breast cancer. Nipple fluid aspiration can be used to classify cyst type (and to some extent improve breast cancer risk prediction) but it is rarely used in practice. Biopsy or fine needle aspiration are rarely warranted.

Fibrocystic breast disease is primarily diagnosed based on the symptoms, clinical breast exam and on a physical exam. During this examination, the doctor checks for unusual areas in the breasts, both visually and manually. Also, the lymph nodes in the axilla area and lower neck are examined. A complete and accurate medical history is also helpful in diagnosing this condition. If the patient's medical history and physical exam findings are consistent with normal breast changes, no additional tests are considered but otherwise the patient will be asked to return a few weeks later for reassessment. Women may detect lumps in their breasts during self-examination as well.

The selective estrogen receptor modulators (such as tamoxifen) reduce the risk of breast cancer but increase the risk of thromboembolism and endometrial cancer. There is no overall change in the risk of death. They are thus not recommended for the prevention of breast cancer in women at average risk but may be offered for those at high risk. The benefit of breast cancer reduction continues for at least five years after stopping a course of treatment with these medications.

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%.

The differential for OSSN includes pterygium, pingueculum, papilloma, solar keratosis, lipoma, lymphoma, chronic blepharoconjunctivitis, inflammation, melanoma, ocular pannus, pyogenic granuloma, kaposi sarcoma, keratocanthoma, mucoepidermoid carcinoma, pseudoepitheliomatous hyperplasia, and adenocarcinoma. While confocal microscopy can be used for diagnosis, biopsy is considered the standard, especially before treatment with a cytotoxic medication.

According to the NIH Consensus Conference , if DCIS is allowed to go untreated, the natural course or natural history varies according to the grade of the DCIS. Unless treated, approximately 60 percent of low-grade DCIS lesions will have become invasive at 40 years follow-up. High-grade DCIS lesions that have been inadequately resected and not given radiotherapy have a 50 percent risk of becoming invasive breast cancer within seven years. Approximately half of low-grade DCIS detected at screening will represent overdiagnosis, but overdiagnosis of high-grade DCIS is rare. The natural history of intermediate-grade DCIS is difficult to predict. Approximately one-third of malignant calcification clusters detected at screening mammography already have an invasive focus.

The prognosis of IDC depends, in part, on its histological subtype. Mucinous, papillary, cribriform, and tubular carcinomas have longer survival, and lower recurrence rates. The prognosis of the most common form of IDC, called "IDC Not Otherwise Specified", is intermediate. Finally, some rare forms of breast cancer (e.g., sarcomatoid carcinoma, inflammatory carcinoma) have a poor prognosis. Regardless of the histological subtype, the prognosis of IDC depends also on tumor size, presence of cancer in the lymph nodes, histological grade, presence of cancer in small vessels (vascular invasion), expression of hormone receptors and of oncogenes like HER2/neu.

These parameters can be entered into models that provide a statistical probability of systemic spread. The probability of systemic spread is a key factor in determining whether radiation and chemotherapy are worthwhile. The individual parameters are important also because they can predict how well a cancer will respond to specific chemotherapy agents.

Overall, the 5-year survival rate of invasive ductal carcinoma was approximately 85% in 2003.