ELECTRON MICROSCOPY (WJH)
Ultrastructurally, the neoplasm consists of sheets of neoplastic
cells containing round to ovoid nuclei many of which contain macro
nucleoli with some chromatin clumping. These appear to be arranged
in a vaguely acinar pattern. The cytoplasm of these cells contain
dilated vesicles of varying diameter, many of which appear to
contain lipid. There is some glycogen present and there is the
paucity of other organelles. In other areas, the neoplasm consists
of roughly rectangular cells arranged along the basement membrane in
a vaguely acinar and papillary configuration. These cells contain
large nuclei with prominent nucleoli and have abundant mitochondria
and an occasional lipid granule. Some of these cells appear to have
short, stubby microvilli and may represent the papillary carcinoma
component of this neoplasm.
Cytogenetic analysis revealed the presence of an abnormal
hyperdiploid clone characterized by additional copies of chromosomes
2, 3, 7, 12, 16, 17, 20 , and loss of chromosome 21. These findings
are consistent with a clinical diagnosis of renal cell carcinoma.
type I and type II
papillary renal cell carcinoma.