Elastic stains in the evaluation of DCIS with comedo necrosis in breast cancers

As concerns the microscopic morphology of ductal carcinoma in situ (DCIS), neoplastic cells are surrounded by both a myoepithelial cell layer and a basement membrane as expected from the outer structure of ducts and lobules. However, in some cases, it is impossible to state whether the structures involved by the disease are ducts or lobules. Altogether 1220 anatomic structures involved by DCIS displaying comedo necrosis from 27 slides of 21 patients (seen on both haematoxylin and eosin-stained and orcein-stained slides) were identified as representing ducts, likely ducts, unclassifiable structures, likely acini or acini on the basis of their distribution and resemblance to normal anatomic structures. All structures were then rated as having a circumferential elastic layer (as normal ducts), a partial elastic layer around more or less than half of the periphery or having no peripheral elastic layer at all (as normal acini). Structures classified as ducts or likely ducts were likely to have an elastic coating, whereas acini and likely acini had no such coating. Unclassifiable structures were generally devoid of an elastic layer. Structures (and cases) that were likely to represent neoductgenesis as proposed by Zhou et al. (Int J Breast Cancer 2014;2014:581706) were generally unclassifiable and devoid of outer elastic layer. Many duct-like structures in DCIS with comedo necrosis are devoid of elastic layer typical of normal ducts, suggesting that these structures are abnormal despite conservation of the myoepithelium and the basement membrane.