A Modification of the Lymph Node
Imprint Technic
PRASERT TANAPATCHAIYAPONG,
M.D.
Histology and Hematology Laboratories, South Side
I'illsburgh,
Pennsylvania
Hospital,
ABSTRACT
Tanapatchaiyapong, Prasert: A modification of the lymph node imprint technic. Am. J. Clin. Pathol. 58: 431-433, 1972. Preparing lymph node imprints
by rolling a glass slide surface on the cut surface of a lymph node and staining with a modified concentration of Wright-Giemsa stain yields excellent
reproducibility and maximum cytologic detail.
have diagnostic value
as an adjunct to, or even as a substitute
for, routine sections.3-10 Technical difficulties arise when a long interval ensues between excision of nodes and preparation
of the imprint, especially when imprints
are prepared by inexperienced workers.
This paper describes a modified technic of
preparing and staining imprints from fresh,
refrigerated, or postmortem lymphoid tissues. The method yields preparations retaining maximal cytologic detail with minimal cell distortion, better overall quality
of imprints and staining results, and a considerable savings of time and effort.
LYMPH NODE IMPRINTS
Procedure
1. Bisect the lymph node with a sharp
scalpel. It is advisable to cut out a wedgeshaped piece at one corner of the bisected
lymph node, to orient the imprint for later
comparison with the stained section.
2. Keep half of the lymph node under
Received September 24, 1971; accepted for publication October 15, 1971.
Presented at the meeting of Pittsburgh Pathology
Society, Pittsburgh, Pennsylvania, April 21, 1971.
Address reprint requests to Doctor Tanapatchaiyapong at his present address: Division o£ Laboratory Services, Manhattan Veterans Administration Hospital, First Ave. at 24th St., New York,
New York 10010.
refrigeration for further microbiologic and
other special studies, or for future staining.
3. If the node is small, place it upon a
piece of aborbent paper on the hand; if
large, anchor it between two fingers witli
Allis tissue forceps (Fig. 1).
4. Apply a clean glass slide lightly to one
edge of the cut surface of the node and
then ROLL the slide over the tissue surface at constant speed until the edge of
the slide has contacted and left the opposite edge of the tissue. The entire maneuver must be performed smoothly. Freeing
the slide by pulling must be avoided
(Fig. 1).
5. Air dry the imprint, if Romanowski's
stain is contemplated. If another staining
procedure is needed, fix the imprint in
appropriate fixative; e.g., ether alcohol for
Papanicolaou stain.
6. Cover air-dried imprints with a measured number of drops of Wright's stain
for 2 min. 1 ' 2
7. Add an equal amount of 0.05 M phosphate buffer solution (pH 6.4 to 6.5). Mix
by rocking and stain for 2 min.
8. Pour off the stain. Do not luasli.
9. Stain for JO min. witli Wright-Giemsa
solution modified as follows:
A. Five ml. of 0.05 M phosphate buffer solution, pH 6.4 to 6.5.
431
432
TANAPATCHAIYAPONG
A.J.C.P.—Vol. 5S
Cut surface of
of lymph node
FIG. 1. Technic for preparing the imprint. Lightly touch one edge o£ the cut surface of the
node with a glass slide and roll over the surface of the lymph node until the glass slide surface
touches the opposite edge, at constant speed, and lift off.
B. Three drops of Giemsa's stain.
C. One drop of Wright's stain.
10. Flush with distilled water.
11. Air dry.
12. Cover with mounting media and
coverslip.
Results and Discussion
Examination of stained imprints reveals
uniformly excellent results on slides prepared from fresh specimens by means of
this technic, as compared with slides prepared by conventional smear or touch
methods. Retention of cytologic detail is
maximized, with more even distribution of
cells, fewer distorted cells, and good coloration of all cellular components. When
performed with modifications to be described, the rolling technic yields results
with equal fidelity from lymphoid tissues
received more than 2 hr. after excision or
death.
In the currently-used smear technic, the
amount of pressure applied between slide
and tissue is not specified, and has not
been studied; results are not consistent or
predictable. If excess pressure is applied,
a majority of cells will be distorted or ruptured. This is especially true of lymph
nodes from which imprints are made more
than 2 hr. after excision or death, since
cells in such nodes are much more fragile.
Breakage or distortion of cells is due to
excess forces created by improper technic.
If the imprint is prepared by touching the
glass slide to the entire cut surface of the
node and then pulling the slide away, a
tension force—augmented by adhesion and
suction—is created; this force can easily
rupture the delicate cell membrane. If the
imprint is prepared by compression and
sliding of the two surfaces, shear forces
which distort or break the cell are created.
Bare nuclei, elongated to a single fiber and
surrounded by cellular debris, are evidence
of such distortion. Consequently, many im-
October 1972
LYMPH
NODE
prints must be discarded because of distortion, breakage of cells, and overlapping
or piling of cells.
In the proposed modification, imprints
are prepared by gently "rolling" the surface of the slide over the cut surface of
the lymph node. Any tangential shear force
is thus eliminated, and, since tissue and
slide are in contact at only one point of
the arc at any given instant, build-up of
adhesion and suction forces is also minimized. Just enough adhesion is created to
lift a layer of cells from the cut surface,
with minimal distortion both of individual
cells and of topographic orientation.
In order to obtain acceptable results, the
lymphoid tissues are handled differently
depending on their condition. According
to the appearance of the cut surface, the
following precautions should be taken:
1. With soft and moist surface: roll glass
slide with constant speed (gently).
2. With mushy or sticky surface: apply
minimal pressure while rolling. This type
represents the most difficult condition, because too much pressure will cause the cells
to pile on top of each other. If too little
pressure is applied, friction and traction
may be greater than the rolling force, causing a shear effect. A proper amount of pressure will counterbalance the friction and
traction, resulting in an adequate contact
between slide and cell membranes without
slippage and resultant distortion. It can be
achieved only by preparing many slides
with different amounts of pressure.
3. With soft and watery surface: wipe
off water with edge of glass slide gently
and proceed. If excess water remains, the
imprint will not reflect topographic orientation.
4. With firm and watery surface: wipe
off excess water and proceed, with slightly
increased pressure.
433
IMPRINTS
5. With firm and moist surface: roll with
a slightly increased pressure.
6. With firm and dry surface: prepare
many slides with various pressures. It is
difficult to prepare good imprints from tissue in this condition, because the cut surface of the tissue cannot be molded. Rolling force cannot be created from two flat
surfaces; it must be between two convex
surfaces, or one convex and one flat surface.
The described approach can be used for
tumor tissues other dian those of lymphoid
origin, such as breast, lung, or gastrointestinal tract. Excellent results have been
obtained.
Acknowledgment. Dr. Sheldon C. Sommers evaluated this paper, Dr. Louis Goodman gave valuable
suggestions, and Dr. Robert E. Wcnk, Dr. A. V.
Roy, Claude Falkenhan, and Jean Hayden helped
in preparation of the manuscript. Helen Y. Zoccolillo, R.B.P., prepared the photographic illustrations.
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