Eble JN, Sauter G., Epstein JI, Sesterhenn IA - iarc
Eble JN, Sauter G., Epstein JI, Sesterhenn IA - iarc
Eble JN, Sauter G., Epstein JI, Sesterhenn IA - iarc
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1553}. The etiopathogenesis of this<br />
tumour is unknown, although it is suspected<br />
that it originates from modified<br />
urothelial cells, that are possibly derived<br />
from basal (stem) cells {1106}.<br />
Hybridization with <strong>Epstein</strong>-Barr virus<br />
encoded RNA has been reported to be<br />
consistently negative in different series<br />
{82,973,1106,1553}. The tumour is solitary<br />
and usually involves the dome, posterior<br />
wall, or trigone, often with a sessile<br />
growth pattern.<br />
Lymphoepithelioma-like carcinoma may<br />
be pure, predominant or focally admixed<br />
with typical urothelial carcinoma, or in<br />
some cases with squamous cell carcinoma<br />
or adenocarcinoma {1106,1553}. The<br />
proportion of lymphoepithelioma-like carcinoma<br />
histology should be provided in<br />
tumours with mixed histology.<br />
Histologically, the tumour is composed of<br />
nests, sheets, and cords of undifferentiated<br />
cells with large pleomorphic nuclei<br />
and prominent nucleoli. The cytoplasmic<br />
borders are poorly defined imparting a<br />
syncytial appearance. The background<br />
consists of a prominent lymphoid stroma<br />
that includes T and B lymphocytes, plasma<br />
cells, histiocytes, and occasional<br />
neutrophils or eosinophils, the latter<br />
being prominent in rare cases.<br />
Carcinoma in situ elsewhere in the bladder<br />
is rarely present.<br />
The epithelial cells of this tumour stain with<br />
several cytokeratin (CK) markers as follows:<br />
AE1/AE3, CK8, CK 7, and they are<br />
rarely positive for CK20 {1106,1553}. In<br />
some cases, it is possible to overlook the<br />
malignant cells in the background of<br />
inflamed bladder wall and misdiagnose the<br />
condition as florid chronic cystitis {1553}.<br />
The major differential diagnostic considerations<br />
are poorly differentiated urothelial<br />
carcinoma with lymphoid stroma;<br />
poorly differentiated squamous cell carcinoma,<br />
and lymphoma {1553}. The<br />
presence of recognizable urothelial or<br />
squamous cell carcinoma does not<br />
exclude lymphoepithelioma-like carcinoma;<br />
rather, the diagnosis is based on<br />
finding areas typical of lymphoepithelioma-like<br />
carcinoma reminiscent of that<br />
in the nasopharynx. Differentiation from<br />
lymphoma may be difficult, but the presence<br />
of a syncytial pattern of large malignant<br />
cells with a dense polymorphous<br />
lymphoid background is an important<br />
clue {1553}.<br />
Most reported cases of the urinary bladder<br />
had a relatively favourable prognosis<br />
A<br />
B<br />
Fig. 2.14 Lymphoepithelioma-like carcinoma of the urinary bladder. A Characteristic syncytial appearance<br />
of neoplastic cells (H&E). B Note the characteristic immunostaining with CK.<br />
when pure or predominant, but when<br />
lymphoepithelioma-like carcinoma is<br />
focally present in an otherwise typical<br />
urothelial carcinoma, these patients<br />
behave like patients with conventional<br />
urothelial carcinoma alone of the same<br />
grade and stage {1106,1553}. Some<br />
examples of lymphoepithelioma-like carcinoma<br />
have been described in the<br />
ureter and the renal pelvis {820,2224}.<br />
This tumour, thus far has been found to<br />
be responsive to chemotherapy when it<br />
is encountered in its pure form {82,623}.<br />
Experience at one institution has shown a<br />
complete response to chemotherapy and<br />
transurethral resection of the bladder<br />
{82,623}. Another series of nine patients<br />
treated with a combination of transurethral<br />
resection, partial or complete<br />
cystectomy, and radiotherapy disclosed<br />
four patients without evidence of disease,<br />
three who died of their disease and<br />
two who died of other causes {1106}.<br />
Lymphoma-like and plasmacytoid<br />
variants<br />
The lymphoma-like and plasmacytoid<br />
variants of urothelial carcinoma are those<br />
in which the malignant cells resemble<br />
those of malignant lymphoma or plasmacytoma<br />
{1618,2272,2571,2933,2949}.<br />
Less than 10 cases have been reported.<br />
The histologic features of the lymphomalike<br />
and plasmacytoid variants of urothelial<br />
carcinoma are characterized by the<br />
presence of single malignant cells in a<br />
loose or myxoid stroma. The tumour cells<br />
have clear or eosinophilic cytoplasm and<br />
eccentrically placed, enlarged hyperchromatic<br />
nuclei with small nucleoli.<br />
Almost all of the reported cases have had<br />
a component of high grade urothelial carcinoma<br />
in addition to the single malignant<br />
cells. In some of the cases, the single-cell<br />
component was predominant on the initial<br />
biopsy, leading to the differential diagnosis<br />
of lymphoma/plasmacytoma. The<br />
tumour cells stain with cytokeratin (CK)<br />
cocktail, CK 7 and (in some cases) CK 20<br />
{2571}. Immunohistochemical stains for<br />
lymphoid markers have consistently been<br />
reported as negative.<br />
Each of these variants of urothelial carcinoma<br />
may cause a significant differential<br />
diagnostic dilemma, especially in cases<br />
in which it constitutes the predominant or<br />
Infiltrating urothelial carcinoma 101