We read with great interest the paper “Inking in Surgical
Pathology: Does the Method Matter? A Procedural Analysis
of a Spectrum of Colours” published in this journal recently
and wish to share our small study relating to the same topic1.
Grossing or macroscopic examination is an integral part
of evaluating any surgical specimen. Tissue inking is
often employed during grossing for various indications,
including identification of resection margins, to assist
specimen orientation and to help identify small tissue
pieces at embedding. Tissue inking is usually performed
using India ink or tissue marking dyes (TMDs). India ink
carries the limitation of being limited to one colour, as
opposed to TMDs which come in various colours. While
TMDs are excellent and are well preserved after processing,
they can be rather costly, especially for small laboratories
in developing countries. Studies have explored alternative
marking techniques which include painting with gelatin2, commercially available oil and acrylic paints3,4, and
other routinely used dyes in histopathology laboratory
such as eosin and Alcian Blue3 as an alternative to TMDs.
However, to the best of our knowledge, the use of locally
available paints as alternative tissue marking techniques in
Malaysia has not been explored.
We performed a study assessing the use of locally available
poster colours (Buncho®, Buncho Marketing Sdn Bhd,
Klang, Selangor, Malaysia) in commonly used shades in tissue inking, which are black (code 31), Prussian blue (code
40) and green (code 45) and directly evaluated the colour
visibility microscopically compared to tissues inked with
TMDs of similar shades. Four different tissue specimens
fixed in formalin were selected (breast, colon, skin and
thyroid) to represent different tissue consistency and the
surfaces for inking. Six tissue pieces were taken from each
specimen; three were inked using TMDs and placed into
one block, while the other three pieces were inked using
poster colours and were placed in a separate block. The
process was repeated for all of the tissue specimens. The
tissues were dabbed dry with paper towels prior to, and after
inking. No additional inking aids were used. The blocks were
then processed using standard processing techniques. The
next day, the tissues were embedded in paraffin, sectioned
at 3mm thickness and stained with haematoxylin and eosin
(H&E). All of the slides were examined microscopically.
The colour visibility on microscopic evaluation was scored
from 0 to 3 (0-No visible colour marking; 1-Faint visibility;
2-Moderate visibility and 3-Strong visibility). The results
are tabulated in Table I. Examples of tissue inked with
TMD and poster colour are shown in Figure 1A,B.
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|Table I: Microscopic colour visibility of different types of tissues
inked with TMDs and poster colours.
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|Figure 1: Thyroid specimen inked with A) TMD (H&E; x10) and B) poster colour in the shade of Prussian blue (H&E; x10).
In general, the visibility of poster colours microscopically
rivalled the TMDs, if not superior, when used without
additional inking aids in the shades that we studied. All
three colours used were reliable; Prussian blue appeared to
be the most consistent. The type of tissue also seemed to
influence colour fidelity with least visibility of the ink seen
when applied on colon serosa, when no mordant was used.
There was minimal seepage of colour into underlying tissue
substance. There was no difference in the quality of the
tissue sections or staining compared to other non-inked
tissues processed on the same day.
Poster colour is a form of acrylic paint, which is widely used
for painting and artwork. As previously demonstrated,
acrylic paints do appear to be a reliable, cheaper substitute
for tissue marking hence providing an excellent option
for financially-constrained small laboratories3-5.
Furthermore, its vast array of available shades of colours
confers an advantage over India ink, gelatin, and even
TMDs. It needs to be borne in mind however that these
alternative paints should be tested in individual laboratories
prior to routine use to ensure reproducibility of the results
when using locally available acrylic / poster paints. We have
since successfully used poster colours in select shades to ink
routine surgical specimens in our laboratory (Figure 2).
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|Figure 2: Routine breast specimen inked using poster colour in
the shade of black (H&E; x10).