A Staging Paradox

Two years ago, this 64 year old woman underwent excision of a retroareolar intraductal papilloma that contained atypical ductal hyperplasia. The case presented below is from a current axillary biopsy.

Image 1.  A lymph node contains an epithelial proliferation.

Image 3.  Fibrous duct wall is lined by a single layer of cuboidal epithelium.

Image 5.  Fibrovascular cores are lined by uniform cells.

Image 2.  Epithelial proliferation has a rounded configuration.

Image 4.  Complex proliferation of uniform cells with low grade nuclei.

Diagnosis:  Low grade ductal carcinoma in situ, involving an intranodal intraductal papilloma.

Discussion:  At the time the patient underwent excision of this lymph node, she also had an excisional biopsy of the ipsilateral breast, which showed intraductal papillomas, one of which was involved by low grade ductal carcinoma in situ (not shown).  Although uncommon, axillary lymph nodes may contain breast tissue, usually in the form of benign glandular inclusions, but occasionally intraductal papillomas may be present.  The latter finding occurs most often when the ipsilateral breast contains intraductal papillomas.  Recognition of this phenomenon can avoid over-diagnosis of metastasis.  This lesion should be staged as Tis, rather than N1.

Reference:  Boulos FI, et al.  Intranodal papillary epithelial proliferations: a local process with a spectrum of morphologies and frequent association with papillomas in the breast. Am J Surg Pathol. 2014 Mar;38(3):383-8.