Diagnostlc factors Renal Adenoma : Identification of Two Histologic Types

In this pa~r the morphologic characteristics of renal adenoma are studied in 4 groups of kidneys from 500 unselected autopsies performed for legal reasons, 5.000 autopsies from the files ofa general hospital, 16 kidneys with adenom3 and without carcinoma, and 200 kidneys with carcinoma. All the tUlnors were classified by pattern. cytology and sclerosis of lhe renal nontl.lmoral stroma The relationship between tumar size, turnor histological type and sclerosis was evaluated by statistical analysis. The differences m frequency were signHicam bctweenlhe parameters size and histological type (p < 0.003), namely for solitary adenomas (p < 0.001). The differences in histological type ohserved in multiple adenomas were 1,o1 significant (p> 0.05). The differences were signif. icant between the extent of sclerosis and histological type (p < 0.002) and tu mar size (p < 0.009). This study identifies two distinct groups of adenomas according to size, histological type and extenl of sclerosis, and suggests Ihat small adenomas of the mixed tubulopapillary type and with basophilic cells have little or no malignant potential. Conversely. adenomas with a solid or papillary pattern and clear cells are potentially malignant.