Images & Graphics

1. Plasmacytoma

Plasmacytomas are not as common as other skin tumors (ie, <1% in dogs, rare in cats). Cells may be well-differentiated and easily recognized as plasma cells or may exhibit atypia. Cells are round with deeply basophilic cytoplasm that tends to stain darker at the margins and paler in the perinuclear zone, which is variably prominent. Nuclei are eccentrically placed and round with coarse chromatin. Binucleated cells are a common and consistent feature, and low numbers of multinucleated cells can also be seen. Plasma cells may have a bright pink cytoplasmic border (ie, flame cell).