[Pathologic analysis of lobular carcinoma of the breast--report of 36 cases].

Thirty-six cases of lobular carcinoma of the breast are reported. It comprised 11% of all the breast carcinomas. All patients were female. There were 6 cases of lobular carcinoma in situ (LCIS) with a mean age of 42 years and 30 cases of infiltrating lobular carcinoma (ILC) with a mean age of 51 years. LCIS was small, millet-size lesion which was usually accompanied with fibrocystic disease of the breast and often accidentally observed by pathologic examination. LCIS was prone to multicentricity, bilateral involvement and developing into ILC. Histologically, LCIS was characterized by intralobular proliferation of the cells lining the acini. The lumen became packed with these cells and progressively disappeared as the lobule became more and more distended. Pleomorphism of the cells was usually minimal. Necrosis was absent and mitosis was extremely rare. When the basement membrane of the acini was destroyed, two types of invasion were observed: first, the cells invaded into the stroma between the acini within the same lobule-so called LCIS with invasion, then the cells spread out of the boundary of the involved lobule and presented as threadlike strands or small nests infiltrated in a dense fibrous matrix. Sometimes the cells formed concentric rings around an apparently dilated duct. It should be pointed out that the mistakes made by pathologists in practics are overlooking LCIS and misinterpreting ILC.(ABSTRACT TRUNCATED AT 250 WORDS)