BREAST CYTOPATHOLOGY

Special Types of Breast Carcinomas 127
Figure 4.46. Metaplastic carcinoma. A dispersed population of
pleomorphic malignant cells appearing as naked nuclei embedded
within a granular, myxoid background. This myxoid stroma should
not be confused with the biphasic appearance of a fibroadenoma.
(Smear, Diff-Quik.)
Carcinoma With Osteoclastic-Type Giant Cells
Clinical Features
• This is a rare variant of high-grade ductal carcinoma NOS
and is characterized by the presence of osteoclastic giant
cells in the stroma.
• A majority of the reported cases had lymph node metastasis,
with a 5-year survival rate approaching 70%, similar to
patients with ordinary infiltrating breast carcinomas.
• The giant cells are present in the stroma and are associated
with an inflammatory, fibroblastic response with extravasated
red blood cells, lymphocytes, and monocytes.
• The giant cells are histiocytic in origin as confirmed by
positive staining for CD68 (KP-1) using immunohistochemistry.
The histiocytic nature of these giant cells has
also been confirmed by ultrastructural studies.
Cytomorphologic Characteristics (Figure 4.47)
• Hypercellular smears
• Osteoclastlike giant cells admixed with carcinoma cells