**6.1 Light microscopy**

At light microscopy, we can say that the prostatic structure is completely disrupted and hardly recognizable. Three different types of cellular necrosis are generally found:

High-Intensity Focused Ultrasound (HIFU)

sporadically small nucleoli.

concentrated in the coagulative necrosis area.


the coagulative necrosis areas is visible in prostatic ductules of the margin area. Brightly staining blood droplets can be observed on the hematoxylin-eosin slide, of which most are

The nuclei of epithelial and stromal cells are either pyknotic or totally absent, corresponding to cell necrosis. The nuclei are of normal size with a fine chromatin structure and

This epithelial cells also contain pale to eosinophilic cytoplasm, with few vacuoles. Although

cell borders are not discernable in most of these cells, they can be identified locally.

Every so often, extended haemorragic areas are found (Fig. 7b).

Fig. 7b. Areas of tissue damage, including haemorragic areas

debris of nuclei, which indicated endothelial cell death.

granulation tissue replacement (Fig. 8).

disrupted.

Also, HIFU causes injuries to small vessels, with considerable oedema and swelling of endothelial cells in the margin between the treated and untreated areas. However, in the centre of treated tumor tissue, severely damaged tumor vessels show pyknotic nuclei and

Endothelial cells exhibited an irreversible cell death. Almost all of the endothelial cell nuclei disappear, cellular margins were not distinct and junctions between individual cells were

The repair of lesions appears to have slow processes of damaged tissue absorption and


Cell death is generally due to a mixture of the three with liquefactive necrosis being the least common and coagulative necrosis the most common.

Histological findings show consistent coagulative necrosis with precisely defined, sharp margins to normal tissue.

Lesion size and position correlates well with the assumed target zones, thus demonstrating that HIFU permits therapeutic tissue ablation.

Strictly speaking, HIFU treatment induces a spectrum of morphological changes ranging from apparent light microscopic necrosis to more subtle ultrastructural cell damage (see below).

Necrotic tissue in the coagulative necrosis areas consists of homogenously stained eosinophilic fragments (Fig. 7a).

Fig. 7a. Areas of coagulative necrosis can be clearly seen, thus demonstrating the effectiveness of HIFU treatment.

Little structure is apparent aside from some faintly staining collagenous bands and rare indications of the former glandular epithelium. In some cases, necrotic tissue expelled from

Cell death is generally due to a mixture of the three with liquefactive necrosis being the least

Histological findings show consistent coagulative necrosis with precisely defined, sharp

Lesion size and position correlates well with the assumed target zones, thus demonstrating

Strictly speaking, HIFU treatment induces a spectrum of morphological changes ranging from apparent light microscopic necrosis to more subtle ultrastructural cell damage (see

Necrotic tissue in the coagulative necrosis areas consists of homogenously stained

Fig. 7a. Areas of coagulative necrosis can be clearly seen, thus demonstrating the

Little structure is apparent aside from some faintly staining collagenous bands and rare indications of the former glandular epithelium. In some cases, necrotic tissue expelled from

a. liquefactive necrosis; b. coagulative necrosis; c. apoptotic necrosis.

margins to normal tissue.

eosinophilic fragments (Fig. 7a).

effectiveness of HIFU treatment.

below).

common and coagulative necrosis the most common.

that HIFU permits therapeutic tissue ablation.

the coagulative necrosis areas is visible in prostatic ductules of the margin area. Brightly staining blood droplets can be observed on the hematoxylin-eosin slide, of which most are concentrated in the coagulative necrosis area.

The nuclei of epithelial and stromal cells are either pyknotic or totally absent, corresponding to cell necrosis. The nuclei are of normal size with a fine chromatin structure and sporadically small nucleoli.

This epithelial cells also contain pale to eosinophilic cytoplasm, with few vacuoles. Although cell borders are not discernable in most of these cells, they can be identified locally. Every so often, extended haemorragic areas are found (Fig. 7b).

Fig. 7b. Areas of tissue damage, including haemorragic areas

Also, HIFU causes injuries to small vessels, with considerable oedema and swelling of endothelial cells in the margin between the treated and untreated areas. However, in the centre of treated tumor tissue, severely damaged tumor vessels show pyknotic nuclei and debris of nuclei, which indicated endothelial cell death.

Endothelial cells exhibited an irreversible cell death. Almost all of the endothelial cell nuclei disappear, cellular margins were not distinct and junctions between individual cells were disrupted.

The repair of lesions appears to have slow processes of damaged tissue absorption and granulation tissue replacement (Fig. 8).

High-Intensity Focused Ultrasound (HIFU)

generally identified.

from peripheral blood.

treated with HIFU13.

including HSP27.

*in vitro* and *in vivo.*

stress (Fig. 9).

remains undefined.

cells14.


Electron microscopy is capable to demonstrate cell necrosis also in areas that show no

Treated areas lack nuclear membranes, but show a fine chromatin pattern that is clumped at

The cytoplasm contain some vacuoles, but organelle structures and cell membranes are not

T-lymphocytes appear in granulation tissue along the ablation margin in all HIFU-treated neoplasms, with no infiltration in those showing typical signs of coagulation necrosis. The tumor-infiltrating lymphocytes are found mainly in granulation tissue along with

This observation suggest that their infiltration occurs after HIFU ablation and that these tumor-infiltrating lymphocytes are new lymphocytes moving into the ablated neoplasms

As it has been reported by Hartveit and colleagues, this is a typical findings in all tissues

HIFU treatment may definitively increase the local infiltration of tumor infiltrating lymphocytes in the ablation area, including activated cytotoxic T-Cells and Natural-Killer

Heat shock proteins (HSPs) were first discovered in 1962 as a group of highly conserved

There are four principal HSP: HSP-90, HSP-70, HSP-60 and the subgroup of small HSPs

Benign and malignant human prostatic cells respond to heat by increased expression of HSP

To obtain a more detailed insight on the effect of heat on prostatic cells, heat shock protein

Transrectal HIFU therapy induces intraprostatic necrosis surrounded by a zone

Recently, several molecular heat shock proteins have been reported to be involved in

HSP27 and HSP70 are the most strongly induced heat shock proteins during cellular

HSPs are not all of prognostic value, however some have been demonstrated to have clinical utility as prognostic markers: among this group of heat shock proteins, the most important one is HSP-27, which particularly plays a role in many immunological processes and might

Accumulating evidence suggests that HSP27 levels correlate with both hormone-refractory prostate cancer and development of resistance to heat. Nevertheless, the functional significance of changes in HSP27 expression associated with heat-resistant prostate cancer

proteins that are induced by hyperthermia and other kinds of cellular insults.

expression of normal and malignant prostatic cells has been studied.

development and progression of hormone-refractory prostate cancer.

characterized by a massive up-regulation of HSP expression.

stimulate immune defence responses against tumour cells15.

apparent morphological cell necrosis by conventional light microscopy.

immature fibroblasts, new capillaries, and other inflammatory cells.

the periphery of the nuclei, and conspicuous nucleoli.

**7. Immunologic response after HIFU** 

**8. The role of heat-shock proteins (HSP)** 

Fig. 8. Granulation tissue and fibrosis 6 months after HIFU treatment.
