Traumatic Transport

A previous core biopsy from this 32 year old woman contained high grade ductal carcinoma in situ.  She underwent mastectomy and sentinel lymph node biopsy.  The mastectomy specimen was thoroughly sampled, and extensive high grade ductal carcinoma in situ, micropapillary type was present, but no invasion.   The sentinel lymph node contained several epithelial clusters in subcapsular spaces.

Image 1.  Numerous lobular units and true ducts are expanded by a proliferation of neoplastic cells that form micropapillary structures.

Image 3.  An epithelial cluster is present in the subcapsular sinus in the sentinel lymph node.  There are numerous hemosiderin-laden histiocytes and degenerating red blood cells.

Image 2.  High grade micropapillary ductal carcinoma in situ with central necrosis.

Image 4.  Degenerating epithelial cell cluster associated with fragmented red blood cells and hemosiderin-laden histiocytes.

Diagnosis:  High grade ductal carcinoma in situ, micropapillary type with necrosis; benign sentinel lymph node

Discussion:  Biopsy procedures of papillary and micropapillary lesions frequently result in mechanical disruption of papillary/micropapillary structures that drain into sentinel lymph nodes, and are found in the subcapsular sinus.  These epithelial structures show cellular degeneration, and are associated with fragmented red blood cells, hemosiderin-laden histiocytes, and occasional giant cells.  This phenomenon of ‘benign transport’ is secondary to mechanical disruption, and not true metastasis;  lymph nodes with these changes should be diagnosed as benign (N0).

Carter B, et al.  Benign transport of breast epithelium into axillary lymph nodes after biopsy.  Am J Clin Pathol 2000; 113:259-65.