20.12.2013 Views

Eble JN, Sauter G., Epstein JI, Sesterhenn IA - iarc

Eble JN, Sauter G., Epstein JI, Sesterhenn IA - iarc

Eble JN, Sauter G., Epstein JI, Sesterhenn IA - iarc

SHOW MORE
SHOW LESS

Create successful ePaper yourself

Turn your PDF publications into a flip-book with our unique Google optimized e-Paper software.

Fig. 1.33 Chromophobe RCC with sarcomatoid dedifferentiation.<br />

A<br />

Fig. 1.34 Chromophobe RCC. A Hale’s iron staining of eosinophilic variant. B Classic variant. Hale’s colloidal<br />

iron stain positivity in the cytoplasm.<br />

B<br />

brown or tan turning light grey after formalin<br />

fixation.<br />

Tumour spread and staging<br />

The majority of CRCCs are stage T1 and<br />

T2 (86%) whereas only 10% show extension<br />

through the renal capsule into surrounding<br />

adipose tissue, only 4% show<br />

involvement of the renal vein (T3b) {512}.<br />

A few cases of lymph node and distant<br />

metastasis (lung, liver and pancreas)<br />

have been described {152,1635,2172}.<br />

Histopathology<br />

In general, the growth pattern is solid,<br />

sometimes glandular, with focal calcifications<br />

and broad fibrotic septa. In contrast<br />

to clear cell renal cell carcinoma, many<br />

of the blood vessels are thick-walled and<br />

eccentrically hyalinized. The perivascular<br />

cells are often enlarged.<br />

Chromophobe renal cell carcinoma is<br />

characterized by large polygonal cells<br />

with transparent slightly reticulated cytoplasm<br />

with prominent cell membranes.<br />

These cells are commonly mixed with<br />

smaller cells with granular eosinophilic<br />

cytoplasm. The eosinophilic variant of<br />

chromophobe carcinoma is purely composed<br />

of intensively eosinophilic cells<br />

with prominent cell membranes {2610}.<br />

The cells have irregular, often wrinkled,<br />

nuclei. Some are binucleated. Nucleoli<br />

are usually small. Perinuclear halos are<br />

common. Sarcomatoid transformation<br />

occurs {2047}. Another diagnostic hallmark<br />

is a diffuse cytoplasmic staining<br />

reaction with Hale’s colloidal iron stain<br />

{475,2608}.<br />

Immunoprofile<br />

Immunohistology presents the following<br />

antigen profile: pan-Cytokeratin+,<br />

vimentin-, EMA+ (diffuse), lectins+, parvalbumin+,<br />

RCC antigen-/+, CD10–<br />

{140,1635,1675,2513}.<br />

Ultrastructure<br />

Electron microscopically, the cytoplasm<br />

is crowded by loose glycogen deposits<br />

and numerous sometimes invaginated<br />

vesicles, 150-300 nm in diameter resembling<br />

those of the intercalated cells type<br />

b of the cortical collecting duct<br />

{722,2515}.<br />

Somatic genetics<br />

Chromophobe renal cell carcinomas are<br />

characterized by extensive chromosomal<br />

loss, most frequently -1,-2,-6,-10,-13,-17<br />

and –21 {338,2464}.<br />

The massive chromosomal losses lead to<br />

a hypodiploid DNA index {42}.<br />

Endoreduplication/polyploidization of the<br />

hypodiploid cells has been observed.<br />

Telomeric associations and telomere<br />

shortening have also been observed<br />

{1113,1375}.<br />

At the molecular level, Contractor et al.<br />

{486} showed that there are mutations of<br />

Fig. 1.35 Chromophobe RCC with typical monosomy<br />

(one signal for chromosome 17). FISH.<br />

Fig. 1.36 Chromophobe renal cell carcinoma. A representative karyotype of a chromophobe RCC showing<br />

extensive loss of chromosomes.<br />

Chromophobe renal cell carcinoma<br />

31

Hooray! Your file is uploaded and ready to be published.

Saved successfully!

Ooh no, something went wrong!