Salivary Gland
10 curated traps and look-alikes for this organ system.
Post-FNA Warthin infarction
Identify ghost outlines of papillary oncocytic epithelium; confirm FNA history; never diagnose SCC without viable malignant cells.
PLGA vs. Adenoid Cystic Carcinoma
Angulated/hyperchromatic = AdCC; bland/uniform = PLGA. CD117 strong = AdCC. Confirm PLGA with PRKD1 if needed.
MASC vs. Acinic Cell Carcinoma
DOG-1 + mammaglobin first. DOG-1+ → AciCC; mammaglobin+/DOG-1− → MASC. Confirm with ETV6 FISH.
LGCCC vs. Salivary Duct Carcinoma
LGCCC is AR−/HER2− and bland; SDC is AR+/HER2+ with apocrine cytology and comedo necrosis.
Metastatic RCC vs. primary clear cell neoplasm
Run CD10 + PAX8 + RCC marker first. p63− favors RCC; p63+ favors primary SG neoplasm.
Pleomorphic Adenoma pseudopodia
Sample peripheral capsule extensively; complete excision, no enucleation.
Hyaline myoepithelioma vs. plasmacytoma
CD138 and κ/λ exclude plasmacytoma; myoepithelioma is CK+ and S100+.
Carcinoma ex PA — missing PA remnant
A totally hyalinized round nodule surrounded by carcinoma = PA remnant. Submit entire specimen.
Warthin vs. MALT lymphoma
Warthin has BENIGN bilayered oncocytic epithelium; MALT has clonal B cells with lymphoepithelial lesions.
Basaloid SCC metastasis vs. BCA or AdCC
Check for keratinization, p16 IHC, and clinical history of head/neck primary.