Source Journal of Veterinary Science
Case Report
Open Access
Cytological Features of Hepatic Epitheliotropic Lymphoma in A Cat
Carlo Masserdotti1*, Gian Piero Salemi2, Elena Gigli3 and Valeria Baldassarre1
1
Laboratorio Veterinario San Marco, Padova, Italy
IDEXX Laboratories, Novara, Italy
3
Clinica Veterinaria 24 Ore, Firenze, Italy
2
*
Corresponding author: Carlo
enriqueorsini@gmail.com
Masserdotti,
Laboratorio
Veterinario
San
Marco,
Padova,
Italy;E-mail:
Abstract
The cytological and histological features of an hepiteliotropic hepatic lymphoma from a cat are described. The cat
was referred because clinical signs indicative of hepatopathy. A fine needle capillary sampling (FNCS) without
aspiration, via the use of a 25 Gauge spinal needle of the hepatic parenchyma was performed. A variable number of
medium-sized, round lymphoid cells, with bluish cytoplasm and round-to-ovoid, sometimes clivated nuclei, with
clumped chromatin, were dispersed around the hepatocytes. These cells were frequently internalised into the
cytoplasm of the hepatocytes, displacing the nuclei were observed in the cytoplasms of hepatocytes, sometimes
displacing the nucleus. Similar features were observed in the histological sections. Immunohistochemistry showed
diffuse CD3 expression of the lymphoid cells. The incorporation of neoplastic cells into the hepatocytes is believed
to be the expression of a mechanism of emperipolesis. At the best of the author’s knowledges, this is the first
description of the cytomorphological features of epitheliotropism expressed by lymphoid neoplastic cells in the liver.
Keywords: cytology, cell block, freeze, cryo, snap, pathology
Received August 19 2014; Accepeted March 25 2015; Published April 2 2015
© 2015 Carlo Masserdotti et al; licensee Source Journals
This is an open access article is properly cited and distributed under the terms and conditions of creative commons
attribution license which permits unrestricted use, distribution and reproduction in any medium.
Editor: Dr. Fabrizio Grandi, Brazil
Case Report
A 9-year-old, Shorthair, male cat was referred because
of loss of weight and vomit; although the cat was alert,
the clinical examination revealed cachexia and icteric
mucous membranes. Evaluation of CBC data showed
the presence of mild (4.84 x109 RBC, reference interval
6.35-9.50 x109), normocytic (MCV 39.5 fL, reference
interval 38.0-49.5 fL) and normochromic (MCHC 34.5
g/dl, reference interval 31.0-35.0 g/dl) anaemia with
leukopenia (WBC 1.4 x103, reference interval 5.011.0
x103) and thrombocytopenia (PLT 114 x103, reference
interval 130-430 x103). Significant changes in serum
biochemistry included an increase in hepatic enzyme
activity (ALT 583 U/L, reference interval 32-87 U/L;
AST 356 U/L, reference interval 15-35 U/L; ALP 112
U/L, reference interval 19-70 U/L; GGT 31 U/L,
reference interval 0.1-0.6 U/L) and of total bilirubin
(Total Bilirubin 2.1 mg/dl, reference interval 0.14-0.26
mg/dl). A test for Feline Immunodeficiency Virus gave
positive results. On the basis of these data, a
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hepatopathy
was
suspected.
Ultrasonographic
investigation showed the presence of mild peritoneal
effusion, hepatomegaly with many hypoechoic areas
with perivascular location and a normal gallbladder. A
fine needle capillary sampling (FNCS) without
aspiration, via the use of a 25 Gauge spinal needle of the
hepatic parenchyma was performed. Three smears were
air-dried and stained with the Wright Giemsa method.
On a bloody background, a high number of hepatocytes
arranged in bidimensional sheets showed a variable
amount of lipofuscin pigment in the cytoplasm, and
some degree of vacuolar changes and round nuclei, with
granular chromatin; a variable number of medium-sized,
round lymphoid cells, with bluish cytoplasm and roundto-ovoid, sometimes clivated nuclei, with clumped
chromatin, were dispersed around the hepatocytes
(Figure n°1A). These cells were frequently internalised
into the cytoplasm of the hepatocytes, displacing the
nuclei. In some samples, a very thin clear line
surrounding the rim of the lymphoid cells in the
cytoplasm of the aggregated hepatocytes was evident
(Figure 1B, C and D). A diagnosis of hepatic lymphoma
with epitheliotropic activity was reported.
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© 2015 Carlo Masserdotti et al; licensee Source Journals. This is an open access article is properly cited
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unrestricted use, distribution and reproduction in any medium.
peripheral displacement of the nucleus (Figure 2A);
biliary epithelium was also diffusely involved. A
definitive diagnosis of hepatic epitheliotropic
lymphoma
was
made.
Immunohistochemical
investigation showed diffuse CD3 expression of the
lymphoid cells (Figure 2B). After euthanasia, requested
by the owner, a complete post-mortem necropsy was
denied.
Discussion
Figure 1: a large number of neoplastic lymphoid cells
surrounds a cluster of hepatocytes (A); the neoplastic
cells are internalised in the cytoplasms of hepatocytes,
displacing the nuclei (B, C, D) 106 (WG, 100X)
Figure 2: histologic sections of liver tissue. Note the
internalization of lymphoid cells into the cytoplasms of
hepatocytes (A); ; HE, x40 objective). Neoplastic cells
are diffusely CD3 positive (B) and locate also among the
cells of biliary ducts (ABC complex, DAB chromogen,
x100 objective)
In order to confirm the cytological results, two wedgeshaped fragments of liver tissue were obtained by
laparatomy, immediately fixed in 4% buffered formalin
and then processed and stained routinely. In periportal
and in midzonal areas, a high number of lymphoid cells
were distributed among regular rows of hepatocytes; in
many instances, these cells were located in the
cytoplasm of the hepatocytes, with a consequent
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Among haematopoietic hepatic neoplasms, malignant
lymphoma is the most frequent type observed (Charles
and al, 2006); an epitheliotropic variant of a T-cell
malignant lymphoma, with marked emperipolesis of the
tumour cells by the hepatocytes, has been previously
described (Ossent et al., 1989; Suzuki et al. 2011).
Emperipolesis is defined as "the active penetration of
one cell by another which remains intact" (Humble et al.
1956). It differs from phagocytosis because the engulfed
cell exists within another cell, remains viable, and can
exit with no physiological or morphological
consequences for either cell (Humble et al. 1956).
Emperipolesis is believed to have no diagnostic
significance and must to be differentiated from
“aggressive” emperipolesis, where neoplastic cells enter
and destroy other cells (Bechtelsheimer et al. 1976). In
normal conditions, T-cells are able to penetrate other
tissue cells because they may move from blood to
lymphoid tissues through, rather than between, the
endothelial cells of the high endothelial venules
(Sorokin 2010). T-cells are also able to infiltrate the
epidermis (Neta, 2008) or the epithelium of mucous
membranes (Coyle and Steinberg, 2004). The most
interesting feature of our case is the presence of
neoplastic lymphoid cells within the cytoplasm of
normal hepatocytes; the overlapping of neoplastic cells
to the hepatocyte membrane is excluded by the presence
of a very thin line surrounding the external membrane
edges of some neoplastic cells in the cytoplasm of
hepatocytes. This represents a true incorporation of
neoplastic cells, according to the mechanism of
emperipolesis. In a previous study, electron microscopy
revealed that neoplastic cells were contained within
hepatocytes: the cell membrane of these internalised
cells was intact and was surrounded by the cell
membrane of the hepatocytes (Suzuki et al. 2011). This
finding suggests that the neoplastic cells had
invaginated into the hepatocyte, rather than directly
crossing the membrane into the cytoplasm. Although a
very low degree of cytoplasmic changes are evident in
cytological samples of this liver, it is not clear whether
the process is directly related to cellular and subcellular
damage; we hypothesise that the marked increase in
hepatic enzyme activity would be a direct consequence
of this damage.
Page 2 of 3
© 2015 Carlo Masserdotti et al; licensee Source Journals. This is an open access article is properly cited
and distributed under the terms and conditions of creative commons attribution license which permits
unrestricted use, distribution and reproduction in any medium.
Conflict of Interest
All authors disclose any financial and personal
relationships with other people or organisations that
could inappropriately influence their work.
References
1.Bechtelsheimer H, Gedgik P, Müller R, Klein H
(1976). Aggressive emperipolese bei chronischen
Hepatitiden. Klinische Wochenschrift, 54, 137-40
2. Charles JA, Cullen JM, Van den Ingh TSGAM, Van
Winckle T, Desmet VJ. Morphological classification of
neoplastic disorders of the canine and feline liver
(2006). In: WSAVA Liver Standardization Group:
WSAVA Standards for clinical and histological
diagnosis of canine and feline liver disease. Edinburgh,
London, New York, Oxford, Philadelphia, St. Louis,
Sydney, Toronto: Saunders Elsevier, pp. 123-124.
3.Coyle KA, Steinberg H (2004) Characterization of
lympocytes in canine gastrointestinal lymphoma.
Veterinary Pathology, 41, 141-146
4.Humble JG, Jaynee WHM, Pulvertaft RJ (1956).
Biological interaction between lymphocyte and other
cells. British Journal of Haematology, 2, 283-294.
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5.Neta M, Naigamwalla D, Bienzle D (2008) Perforin
expression in feline epitheliotropic cutaneous
lymphoma. Journal of Veterinary Diagnostic
Investigation, 20, 831-835.
6.Ossent P, Stöckli RM, Pospischil A (1989)
Emperipolesis of lymphoid neoplastic cells in feline
hepatocytes. Veterinary Pathology, 26, 279-280.
7.Sorokin L (2010). The impact of the extracellular
matrix on inflammation. Nature Review Immunology,
10, 712-723.
8.Suzuki M, Kanae Y, Kagawa Y, Ano N, Nomura K,
Ozaki K, Narama I (2011). Emperipolesis-like invasion
of neoplastic lymphocytes into hepatocytes in feline Tcell lymphoma. Journal of Comparative Pathology, 144,
312-316.
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