Mammary intra-epithelial neoplasia

Terminology

High molecular weight cytokeratins may be useful in distinguishing usual ductal hyperplasia from in situ carcinoma

Atypical ductal hyperplasia stains for pure epithelial cytokeratins (CK7, CK18, CK19), while usual interstitial hyperplasia shows a mix of luminal and basal cytokeratins (CK5/6, CK7, CK14, CK18, CK19)4. Atypical hyperplasia and DCIS express high levels of oestrogen receptors in nearly all cells, while usual epithelial hyperplasia shows heterogeneous expression4.

Differentiating ductal (DCIS, DIN) from lobular (LCIS, LIN) intra-epithelial mammary hyperplasia can usually be performed on H/E microscopy. However, some cases show an intermediate morphology, and may be designated as mammary intra-epithelial neoplasia (MIN). In particular, the solid variant of low grade DCIS (DIN 1c) may closely resemble CLIS. The combined e-cadherin and HMW cytokeratin immunoprofile may be useful in these cases. However, some cases also show a hybrid immunoprofile which differs from both classical lobular and classical ductal intra-epithelial neoplasia: further research is needed into such cases.

Optimum staining for 34ßE12 required a heat-retrieval method. Note that other studies have shown that low grade DIN 1a (intraduct hyperplasia, IDH) is immunoreactive for 34ßE122.

References

1 Bratthauer, G. L., F. Moinfar, et al. (2002). "Combined E-cadherin and high molecular weight cytokeratin immunoprofile differentiates lobular, ductal, and hybrid mammary intraepithelial neoplasias." Hum Pathol 33(6): 620-7.

2 Moinfar, F., Y. G. Man, et al. (1999). "Use of keratin 35betaE12 as an adjunct in the diagnosis of mammary intraepithelial neoplasia-ductal type--benign and malignant intraductal proliferations." Am J Surg Pathol 23(9): 1048-58.

3 Lerwill, M. F. (2004). "Current practical applications of diagnostic immunohistochemistry in breast pathology." Am J Surg Pathol 28(8): 1076-91.

4 Putti TC, Pinder SE, Elston CW, et al. Breast pathology practice: most common problems in a consultation service. Histopathology 2005; 47:445-57

This page last revised 17.9.2004.

©SMUHT/PW Bishop