Neovascularisation in tumours of different
cell origins has been well documented qualitatively. In
this report, we have assessed vascular architecture in
different pathological lesions of the colorectum by
quantifying blood vessel parameters in order to detect
subtle morphological changes using objective methods.
Colorectal tissue samples were obtained from
resected large bowels containing malignant tumours.
Biopsies were taken from defined sites in the resected
specimen and were classified as normal (N), potentially
premalignant mucosa (PPM), adenomatous polyp (P)
and adenocarcinoma (ADCA). Al1 tissues were fixed
in modified Karnovsky's fixative for 4 hrs and postfixed
in 1% Oso4 for 1 hr. Samples were processed for
EM under standardized procedures and embedded
in Epon. 0.5 pm semithin sections from five patients
per group were stained with toluidine blue. A multistage
systematic sampling procedure was adopted. The
imer outlines of al1 blood vessels in the lamina propria
(LP) were digitised using a Zeiss VIDAS Image
Analyzer at a final magnification of ~1,050T. he area of
the reference (LP) was also measured. No attempt was
made to distinguish between the different types of
vessel. The morphometric blood vessels parameters
quantified were volume density (V,), numerical density
(NA), length density (LV) and mean transverse sectional area (A).
Statistically significant differences in Vv and A were
detected between al1 groups except between N and PPM
and between P and ADCA. No significant differences in
NA and LV were present in any group comparisons. The
mean values of al1 parameters were the highest in
ADCA. Our results suggest that vasodilatation occurred
in order to provide an increased supply of nutrients to
support active growth and division of the transforming
cells. Such vasodilatation might also reflect the
inflammatory response to the presence of actively
growing malignant cells since activated immune cells
are able to release vasoactive substances
