of False Neoplastic Site ([dagger]) dagger]) Diagnoses by Pathologists Liver 180 37 Hepatocellular adenoma, 36 Hepatocellular carcinoma, 21 Benign neoplasm NOS, 5 Metastatic carcinoma NOS, 1 Metastatic small cell carcinoma, 1 Adenocarcinoma (primary or metastatic), 2 Pancreas 171 10 Islet cell or neuroendocrine tumor, 12 Microcystic adenoma, 1 Lympoma, 1 Adenocarcinoma, 1 Carcinoma NOS, 1 Benign neoplasm NOS, 1 Salivary 272 6 Acinic cell carcinoma, 4 gland Squamous cell carcinoma, 2 Monomorphic adenoma
, 3 Adenoid cystic carcinoma, 1 Warthin tumor, 1 Benign neoplasm NOS, 5 Kidney 102 60 Renal cell carcinoma, 59 Angiomyolipoma, 1 Metastatic carcinoma NOS, 1 * FNA indicates fine-needle aspiration; NOS, not otherwise specified.
Because PLGAs share many of the histologic characteristics of pleomorphic adenomas, monomorphic adenomas
, adenoid cystic carcinomas, and low-grade papillary adenocarcinomas, these other tumors should be considered in the differential diagnosis of PLGA.
It is our opinion, as well as that of Barnes et al  and Dardick et al  that salivary adenomas are part of a spectrum, with monomorphic adenoma
and myoepithelioma at the extremes and a wide range of pleomorphic adenomas in between, depending on the type and degree of gene expression that is coupled with neoplastic transformation.