DCIS (ductal carcinoma in situ)  DCIS originates in the ducts (hence ductal). The abnormal cells have not spread outside the ducts to other tissues in the breast. Left untreated it may develop into malignancy and become invasive. 

Malignant types of breast cancer:

Invasive (infiltrating) ductal carcinoma - this is the most common type of breast cancer, it starts in the ducts, breaks through the wall of the ducts and spreads to the surrounding tissue of the breast. Two less common subtypes include:-

• Mucinous (colloid) carcinoma - its presenting symptom is production of mucous containing malignant cells. 
• Tubular carcinoma - it can be well recognized under the microscope. This particular kind of carcinoma appears as tube-shaped cells under the microscope (hence tubular).
• Medullary carcinoma - specific type of malignancy in which the tumour borders are clearly defined.
• Inflammatory - this is a rare but aggressive condition in which the abnormal cells grow along  lymph vessels in the skin of the breast and block them. This results in the breast looking red and inflamed, and feeling warm and swollen. 

Invasive lobular carcinoma - this condition starts in the milk producing glands (lobules). This form of the disease is more likely to show up as a thickening of the tissue rather than as a firm lump. It is more likely to present in both breasts simultaneously and it does have a slightly higher risk of recurring in the adjacent breast later.

Less commonly 

• Sarcoma - develops in the connective tissue.

• Paget's disease - starts in the milk ducts and spreads to the skin of the nipple and aerola (dark area of the skin surrounding the  nipple). It presents as itchiness and scaling of the nipple and is commonly mistaken for eczema.

• Phylloides tumour - usually a large fleshy mass developing in the connective tissue rather than in ducts or lobules.

• Metastases - spread of disease from other sites in the body.

Further general information Your doctors and specialist nurses are in an ideal position to give you relevant information on your disease and treatment as they know your individual circumstances. Cancerbackup has a help line (0808 800 1234) and a prize winning video available in English, Italian, Urdu, Bengali, Gujarati & Hindi explaining Radiotherapy & Chemotherapy. Cancernet.co.uk has over 500 pages describing cancer, its management, practical tips and tool which patients, their carers and their doctors have found helpful during the cancer journey.