Does this breast lesion make the grade?

 
Image 1:  A low power magnification of two cores showing a vascular proliferation within fat and fibrous stroma.

Image 1:  A low power magnification of two cores showing a vascular proliferation within fat and fibrous stroma.

Image 2:  Higher power shows diffusely anastomosing vascular channels.  Nuclear enlargement and moderate endothelial 'tufting' is present.  A small amount of mammary parenchyma (arrow) is present.

Image 2:  Higher power shows diffusely anastomosing vascular channels.  Nuclear enlargement and moderate endothelial 'tufting' is present.  A small amount of mammary parenchyma (arrow) is present.

Image 3:  Nuclear enlargement and moderate pleomorphism is present in this more solid area of vascular proliferation.

Image 3:  Nuclear enlargement and moderate pleomorphism is present in this more solid area of vascular proliferation.

Diagnosis:  Angiosarcoma.

Discussion:  Angiosarcoma of the breast is extremely rare, and may occur de novo or following radiation.  The peak incidence is between the ages of 30 and 50 years.  Although traditionally breast angiosarcomas are graded using a 3-tiered grading system, Nascimento et al. have shown no correlation between grade and outcome in a study of 49 patients with angiosarcoma of the breast.  Statistical analysis evaluating correlation between tumor grade and size, and rate of local recurrence, metastasis, and death owing to disease showed no significant difference among tumors of different grades. The median recurrence-free and overall survival rates for the entire cohort were 2.8 and 5.7 years, respectively.  This tumor seems to have an overall similar clinical course as other types of angiosarcoma arising in skin or soft tissue (Nascimento AF, Raut CP, and Fletcher CD.   Primary angiosarcoma of the breast: clinicopathologic analysis of 49 cases, suggesting that grade is not prognostic.   Am J Surg Pathol. 2008 Dec;32(12):1896-904. doi: 10.1097/PAS.0b013e318176dbc7).  http://www.ncbi.nlm.nih.gov/pubmed/18813119

Differential diagnosis:

Image 4:  Pseudoangiomatous stromal hyperplasia.  Dense collagenous stroma contains angulated, interconnecting slit-like spaces that are empty and lined by flattened myofibroblasts.

Image 4:  Pseudoangiomatous stromal hyperplasia.  Dense collagenous stroma contains angulated, interconnecting slit-like spaces that are empty and lined by flattened myofibroblasts.

Image 5:  Capillary hemangioma.  Incidental finding in a patient undergoing excision for atypical ductal hyperplasia (not shown).  Lobular configuration of rounded spaces, lined by bland endothelial cells containing red blood cells. 

Image 5:  Capillary hemangioma.  Incidental finding in a patient undergoing excision for atypical ductal hyperplasia (not shown).  Lobular configuration of rounded spaces, lined by bland endothelial cells containing red blood cells.