BREAST CYTOPATHOLOGY

Metastatic Tumors 149
Figure 5.15 Metastatic squamous cell carcinoma of the lung. The
carcinoma is poorly differentiated and shows large syncytial tissue
fragments. No keratinization is evident. (Smear, Papanicolaou.)
• Based on the site of the origin of the tumor, the aspirates
may present with various cell types, including pleomorphic
and spindle shapes, with varying sizes and cellular
arrangements.
• Some of the metastatic tumors may resemble primary
breast tumors such as squamous, clear cell, or mucinous
carcinomas.
• Malignant melanoma (see Figures 5.12 to 5.14), squamous
cell carcinoma (see Figure 5.15), various adenocarcinomas,
and pleomorphic sarcomas exhibit a pleomorphic population
of large cells.
• Melanoma, lymphoma, leukemia, and poorly differentiated
carcinomas present with a dispersed cell pattern.
• Malignant melanoma cells may contain pigment and/or
intranuclear inclusions and they can be bi- or multinucleated
(see Figures 5.12 to 5.14).
• Neuroendocrine tumors and small cell carcinoma of the lung
present with small-sized tumor cells (see Figure 5.6 and 5.7).