Pseudomyxoma peritonei: cytomorphologic findings and clinicopathologic correlates

PP is uncommonly encountered in routine cytopathology practice. The common denominator is the presence of an often-abundant extracellular mucin. Epithelial (glandular) component is usually scant. An accurate diagnosis in a fluid specimen requires proper identification of free/extracellular mucin as well as distinguishing the often “benign-appearing” epithelial cells from reactive mesothelial cells and histiocytes.