Case 338 -- A Palpable Breast Mass

Contributed by Melina Flanagan, MD, MSPH and Swaminathan Rajendiran, MD
Published on line in January 2003


This patient is a 43-year-old African American woman who presented to her doctor with a palpable left breast mass that had been enlarging for two months. Her previous clinical history was significant only for diabetes. An ultrasound guided core needle biopsy was performed.


The specimen consisted of multiple smooth rubbery, yellow-gray fragmented cylindrical cores ranging from 0.4 to 1.8 cm in length and each 0.2 cm in diameter.


The specimens consist of cores of fibrocollagenous tissue with an extensive lymphoplasmacytic infiltrate; in between this infiltrate are large pale cells suggestive of histiocytes (Figure 1). These cells have abundant, eosinophilic, focally foamy cytoplasm. The nuclei are round to oval, vesicular, with one to two nucleoli. Some cells appear to have intact lymphocytes in their cytoplasm. There is no evidence of increased mitosis or necrosis. No breast parenchyma is identified.

Staining for GCDFP and Cytokeratin AE1/ AE3 is negative, indicating that this is not a breast epithelial carcinoma. The large pale cells stain positive for CD68, confirming that they are histiocytes (Figure 2). CD138 highlights scattered plasma cells (Figure 3), and CD3 and L26 highlight the lymphocytic infiltrate (Figures 4 and 5). The histiocytes are strongly S-100 positive (Figure 6) and are CD1a negative (Figure 7). S-100 also highlights the emperipolesis (lymphocytes within the cytoplasm of the histiocytes) (Figure 8).


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