Type of Preparation:
Direct Smear
Magnification:
Low Power Magnification
Interpretation:
Fig. 5.1a Neoplasm: Benign: Pleomorphic Adenoma (PA)
Cytomorphologic Criteria:
• Distinctive chondromyxoid matrix: Best appreciated using Romanowsky stains
(Diff-Quik®, Giemsa), as a bright magenta matrix with a distinct fibrillary/feathery
quality; grey to translucent green in Papanicolaou-stained preparations
• Myoepithelial cells: Variety of shapes (polygonal, plasmacytoid, round, spindle,
and clear), bland nuclear features, often the predominant cell type (Fig. 5.2)
• Ductal epithelial cells: Bland nuclear features, small groups recapitulating ductal
structures
• Iconic PA:Modestly cellular with readily identifiable, abundant fibrillar matrix,
bland ductal epithelial and myoepithelial cells
Explanatory Notes:
PA is one of several “matrix-producing tumors” that also includes adenoid cystic
carcinoma (AdCC), basal cell adenoma/adenocarcinoma, and epithelialmyoepithelial carcinoma. The hallmark and most distinguishing feature of PA is the presence of chondromyxoid matrix Distinctive chondromyxoid matrix: Best appreciated using Romanowsky stains (Diff-Quik®, Giemsa), as a bright magenta matrix with a distinct fibrillary/feathery quality; grey to translucent green in Papanicolaou-stained preparations.