kidney, covered by a connective tissue capsule, is divided
into two main components; an outer cortex and an inner medulla.
cortex (left of slide) contains numerous glomeruli (or renal
corpuscles), renal tubules and blood vessels. At relatively low power, circular
glomeruli surrounded by a clear area called Bowman’s capsule
(or space) can be seen. At high power, glomeruli are seen to be composed
of bundles of capillaries lined by fenestrated endothelial cells.
The endothelial cells lay on a basement membrane whose outer surface
is lined with podocytes. Mesangial cells are dispersed throughout
the capillary tuft. Parietal epithelial cells line the outer wall
of Bowman's capsule. At high power, afferent and efferent arterioles
may be seen entering and leaving the glomeruli, respectively. The remaining
cortical parenchyma is filled with renal tubules. Proximal convoluted
tubule cells are columnar, acidophilic and have densely packed
microvilli at their luminal surface, creating a brush border. Distal
convoluted tubule cells are cuboidal and have no brush border.
Use these characteristics to distinguish between tubules in this slide. The
macula densa is the point of contact between the distal convoluted tubule
and the glomerular afferent arteriole.
medulla (right of slide) is composed of pyramid-shaped units
called medullary pyramids with convey collecting ducts from numerous
nephrons. Collecting ducts, have a simple cuboidal epithelium. Glomeruli
are not seen in the medulla.
infiltration of polymorphonuclear leukocytes (PMNs) is seen in
renal tubules, as well as in the interstitial tissue in this slide. PMNs
(mainly neutrophils) are blood cells with tri-lobed nuclei. Tubules
may be necrotic. The glomeruli appear relatively normal.
interstitial and tubular inflammatory infiltrate can be identified in
this section of chronic pyelonephritis. Some of the tubules appear atrophied,
dilated, and contain eosinophilic hyaline casts. The tubules are
surrounded by interstitial fibrosis.
The section on the left side of the slide, at low power, demonstrates pale
islands of neoplastic cells along the left border of the section. This
is a malignant tumour of renal tubular and ductal epithelial cells.
At high power, the tumour cells are large with abundant clear cytoplasm
and central nuclei. The remaining kidney darker staining renal cortex
appears normal (see kidney above).
malignant neoplasm composed of stromal (less cellular
area), epithelial (spindle-shaped cells) and blastemal (tightly
packed small blue round cells) elements.
ureter is the darker stained circular structure located near the
centre of this tissue section. It’s lumen in lined by multiple layers
of transitional/urothelial cell epithelium. The top layer
of cells are the largest and are called umbrella cells. The deepest
layer of cells are the smallest, appear crowded and are called basal
cells. The epithelium lies on a dense collagenous lamina propria
and three smooth muscle layers; inner longitudinal, middle circular and
outer longitudinal. The ureter is surrounded by adipose tissue and blood
bladder, like the ureter, is lined by transitional epithelium.
Beneath the epithelium and its underlying connective tissue, the wall of
the bladder contains smooth muscle arranged in inner longitudinal, middle
circular, and outer longitudinal layers.
cell carcinoma of bladder:
low power on this slide, the mucosa is the purple-stained tissue lining the
folds of the bladder wall. The tumour cells arise from the epithelium and
infiltrate in sheets and nests into the stromal tissue. Well-circumscribed
nests of deeply staining tumour cells can be identified within and below
the epithelium along the inferior portion of the slide. Keratinized
tumour cells, at low power, are polygonal, have well defined cell borders,
amphophilic to eosinophilic “glassy” cytoplasm and pleomorphic
nuclei with prominent nucleoli.
cell carcinoma of bladder:
cells in transitional cell carcinoma of the bladder are arranged in a papillary
pattern, which can be seen throughout this slide. Multiple layers of
atypical transitional epithelium line delicate fibrovascular cores. At high
power, the tumour cells have clearly defined borders, small nuclei and