LOBULAR CARCINOMA IN SITU (LCIS)
As of January 1, 2018, lobular carcinoma in situ is not considered pTis (AJCC8) in staging, but benign. But there is a high risk of unilateral or bilateral breast cancer. An NSABP study with 180 patients with LCIS and a follow-up of 12 years showed the occurrence of unilateral invasive cancer in 5% and bilateral cancer in 5.6%. More recent data published in 2017 by SEER (Surveillance Epidemiology and End Results) on 19,462 LCIS patients (mean age 53.7), showed a 10- and 20-year breast cancer incidence of 11.3% and 19. =.8% respectively. PLCIS (pleomorphic lobular carcinoma in situ) subtype can coexist with invasive cancer in 40% or with DCIS in 15%.
ADH (ATYPICAL DUCTAL HYPERPLASIA)
It is a benign breast condition but with a high risk of turning into breast cancer. It is characterized by a cellular hyperplasia with an architectural abnormality in the arrangement of the cells, without necrosis. The histopathological features are similar to those of a well-differentiated ductal carcinoma in situ (DCIS).
It is not a scar but a focal radial, uncircumscribed lesion, combined with changes of adenosis, papillomatosis or diffuse intraductal hyperplasia. When they are larger than 6-7 mm. there is a possibility that they contain cancer cells. Histologically, the diagnosis will be made using immunohistochemistry.
FLAT EPITHELIAL ATYPIA FEA (Flat Epithelial Atypia)
These are high-risk architectural abnormalities for breast cancer.
Cystosarcoma phyllodes is a fibroepithelial tumor. Sonographically it is similar to fibroadenoma. Unlike fibroadenoma, Cystosarcoma phyllodes can grow very large in a short period of time and has increased perivascular positivity. It can be of low and high malignancy. In the case of high malignancy, the stroma may contain elements such as liposarcoma, leiomyosarcoma, angiosarcoma. If the removal of the F.C. is not complete, there is a risk of local recurrence and hematological metastasis to the lung, bones (more rarely).
Breast papillomas can be single or multiple, central or peripheral. They usually appear in women aged 30-50. Solitary papillomas are usually located behind the nipple (intraductal papilloma) and often appear as intraductal hyperplasia. The most common symptom is that the nipple discharge is usually bloody and may be accompanied by itching or soreness of the nipple, or a small lump behind the nipple. The lesion should be surgically removed.