Contributed by Melina Flanagan, MD, MSPH, and Leon Barnes, MD
Published on line in April 2006
This patient is a 68-year old female with a right parotid mass. No additional history was available. Parotidectomy was performed. Specimen consisted of a 4.5 x 4 x 1.3 cm parotid containing a 0.6 cm poorly demarcated firm white-tan nodule.
MICROSCOPIC DESCRIPTION AND IMMUNOHISTOCHEMISTRY:
The parotid contains a small well-circumscribed nodule with a proliferation of ducts lined by bland epithelium with finely dispersed chromatin and small nucleoli (Figures 1, 2, 3, 4, 5, and 6). Overall, the morphology resembles an in situ ductal breast carcinoma. Ductal epithelial cells are positive for pankeratin (Figure 7), cytokeratin AE1-3 (Figure 8), and S-100 protein (Figure 9). Rare cells are positive for Estrogen receptor (Figure 10). E-cadherin is positive (Figure 11). P63 and smooth muscle actin outline the myoepithelial layer (Figures 12 and 13). C-kit is focally positive (Figure 14). Mucin is positive (Figure 15). The proliferative index is low by Ki-67 staining. Cells are negative for Androgen receptor, Progesterone receptor, Her-2 neu and GCDFP.