This year’s 52-year-old Li Mou, in early June 2015 a chance to find their own side of the breast redness, swelling, within a few weeks, diffuse half of the breast. Was diagnosed as “acute mastitis” by the local hospital, and received anti-inflammatory, topical Chinese medicine treatment, four months past the condition is getting worse, and feel the left armpit enlarged lymph nodes. Recently, she was diagnosed as inflammatory breast cancer in the breast department of the hospital based on typical clinical manifestations and pathological examination, and began to receive regular comprehensive treatment. Inflammatory breast cancer (IBC) is a rare clinical type, a special type of breast cancer with high invasiveness, accounting for 1%~6% of breast cancer. The disease progresses rapidly and the prognosis is poor. Diagnosis is mainly based on characteristic clinical manifestations and pathology. Main clinical manifestations: rapid enlargement of breast with redness, swelling, heat and pain of skin and orange peel-like appearance. Due to its high degree of malignancy, the cancer cells are diffuse in the pathologic section, and a large number of cancer cells are filled in the breast and breast lymphatic vessels. It is very similar to acute mastitis and thus often misdiagnosed. The majority of cases occur in postmenopausal women, with about 20% occurring during pregnancy or breastfeeding. According to the diagnostic criteria of the American Cancer Consortium (AJCC), the diagnosis of IBC is mainly based on the patient’s clinical manifestations: (1) characteristic orange peel-like changes of the breast skin (red or purple skin with edema, thickening, and increased skin temperature), with more than 1/3 of the breast skin affected; (2) rapid progression of the skin symptoms; (3) tissue biopsy; and (4) pathological examination of the IBC pathology, in which the tumor cells infiltrate into the vasculature system, which manifests as Pathological examination of IBC commonly shows infiltration of tumor cells into the vascular system, which is manifested as dilatation of subcutaneous lymphatic vessels with clusters of tumor cells, i.e., dermal lymphatic embolus. However, dermal lymphatic infiltration is seen in only 75% of IBC pathology. According to the latest diagnostic criteria for IBC, dermal lymphatic infiltration is no longer necessary for the diagnosis of IBC. Inflammatory breast cancer and acute mastitis are difficult to distinguish in the early stage, and inflammatory manifestations such as redness, swelling, heat and pain in the breast can be seen, but the skin redness and swelling in acute mastitis can be more limited or extensive, and the color is bright red; whereas, in inflammatory breast cancer, the skin changes are extensive, and often involve the whole breast, which is like an “orange peel”; and the axillary lymph nodes can be seen enlarged, but the axillary lymph nodes in acute mastitis can be seen swollen, but the lymph nodes in acute mastitis can be seen swollen, but the lymphatic infiltration in the axillary lymphatic vessels can be seen in the breast. The axillary lymph nodes of acute mastitis are relatively soft, with no adhesion to the surrounding tissues and good mobility; while the axillary lymph nodes of inflammatory breast cancer are enlarged and hard, with poor mobility; from the point of view of systemic symptoms, acute mastitis is often characterized by obvious systemic inflammatory reactions such as chills and high fever, while inflammatory breast cancer usually has no obvious systemic inflammatory reactions; from the point of view of disease course, acute mastitis is of short duration, and anti-inflammatory treatments are effective, with a good prognosis; while inflammatory breast cancer is of fierce condition. Inflammatory breast cancer, on the other hand, is very dangerous and usually does not have pus, but can extend to the neck and arm other than the ipsilateral breast, and even invade the opposite breast, and anti-inflammatory treatment is ineffective, with poor prognosis. As the disease progresses, the difference becomes more and more obvious. If inflammatory breast cancer is misdiagnosed and mistreated for too long, it will be very difficult to treat. Therefore, differential diagnosis of these two diseases is very important for patients. Patients who have red, swollen, hot and painful breasts in the early stage should go to regular hospitals for consultation and treatment in time to avoid delay. Clinically, due to the young age of onset of IBC, rapid progression, easy to misdiagnose in the early stage, and difficult to treat in the late stage, the survival period is very short and the mortality rate is very high, which seriously jeopardizes the life of young women. Because IBC is rare, it is not easy to be studied in the clinic, and so far clinicians lack a comprehensive understanding of its clinical manifestations, pathologic features, imaging features, and treatment methods. In view of the fact that IBC is rare and has a short survival period, a multicenter and multidisciplinary alliance is needed to carry out research in this area. In this regard, the Breast Cancer Expert Group held the First International Conference on Inflammatory Breast Cancer in Houston, Texas, USA, in December 2008, and reached a basic consensus on the diagnostic criteria of IBC. The consensus was that the minimum criteria for the diagnosis of IBC should include: (1) rapidly enlarging breast with diffuse erythema and edema, with or without an orange peel appearance, with or without an intramammary mass; (2) onset of disease of less than 6 months; (3) erythema diffusely involving at least one-third of the breast; and (4) histologic confirmation of invasive breast cancer. The consensus states that the diagnosis of IBC should be confirmed by a fine needle aspiration biopsy to confirm invasive carcinoma. In addition, the consensus strongly recommends that every suspected patient undergo a skin biopsy with a fine needle aspiration at least twice, and that every patient with IBC should have hormone receptor (ER and PR) and HER-2 levels tested to aid in the diagnosis and to guide subsequent treatment. According to a recent study in 2011, the number of new breast cancer cases worldwide has increased annually over the past 30 years (1980-2010), with an annual growth rate of 3.1%. 1,643,000 (1,421,000-1,782,000) breast cancer patients were diagnosed globally in 2010, and based on the fact that the number of IBCs accounted for 2.5% of the total number of breast cancers, it is estimated that there are about 41,075 cases of IBCs worldwide each year. Calculating on the basis that IBC accounts for 2.5% of the total number of breast cancer cases, it is estimated that there are about 41,075 new cases of IBC in the world every year, which is a significant number. Since IBC has a very poor prognosis and high mortality rate, this highlights the importance of prevention, and Fredika et al. summarized the major risk factors for IBC, which provides a feasible approach to prevention. According to the latest registry results of M. D. Anderson Cancer Center in December 2009, age of onset is clearly related to the occurrence of IBC, and the average age of onset of IBC is 55 years old, and there are also factors such as early age of menarche, late age of menopause, and high body mass index, etc. It is also shown that the incidence rate of IBC in Africans is 50% higher than that in Caucasians, and the occurrence of IBC shows obvious geographical characteristics. The incidence of IBC is also geographically specific. Risk factors include younger age at onset, younger age at menarche, younger age at first birth, obesity, use of oral contraceptives, number of pregnancies, negative hormone receptor levels, family history of breast cancer -HPV/HHV infection, smoking, alcohol use, and use of non-steroidal anti-inflammatory drugs (NSAIDs).