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Primary Lymphoepithelioma-Like Carcinoma of Lung
Figure 1. Computed tomography scan of the chest showing a peripheral
heterogenous mass in the left lung.
Figure 3. Photomicrograph showing the tumor cells with strong
membranous staining by CAM 5.2. Surrounding lymphoid elements are
not decorated by this epithelial marker (CAM 5.2 stain, original
magnification ×200).
equal sex ratio.3–5 There is an association with EBV, and
interestingly, this association has been proven in almost
all Asian patients, but it is uncommon in Caucasians.
Numerous techniques have been used to demonstrate the
virus, including in-situ hybridization for EBV-encoded
small nuclear ribonucleic acids, demonstration of EBV-
deoxyribonucleic acid in the tumor cells, and expression
of latent membrane protein-1 by immunohistochemistry.1,2,6
While lymphoepithelioma-like carcinoma is rarely seen
as a primary lung lesion in the non-Asian population,
there are no distinguishing features to separate this tumor
from a metastasis; therefore, a thorough evaluation of
other primary sites such as the nasopharynx should be
carried out. The incidence of metastasis to local lymph
nodes is 25%; although hematogenous metastasis occurs
seldom, the skeletal system is the preferred site.4,7 From
the limited data available, the behavior of lymphoepi-
thelioma-like carcinoma of lung is highly variable but
it is not an aggressive malignancy in the majority of
cases.3,6,7 This may be because it often appears as a
peripheral coin lesion, and is diagnosed at an early stage.
However, other factors inherent to the nature of the
carcinoma may play a role in its relatively good prognosis.
Figure 2. Photomicrograph of the tumor showing islets of epithelial-
appearing cells separated by stroma rich in lymphocytes and plasma
cells. Lymphocytes also extend into the tumor aggregates (hematoxylin
and eosin stain, original magnification ×200).
morphism, prominent nucleoli, and mitotic activity
(Figure 2). There was no evidence of tumor differentiation
in the form of glands or keratin pearl formation. Tumor
aggregates were separated by a dense infiltrate of
lymphocytes and plasma cells, which extended into
the neoplastic islets (Figure 2). Immunocytochemistry
revealed epithelial cells decorating with CAM 5.2 and
cytokeratin 5/6, but these were negative for cytokeratins
7 and 20 (Figure 3). Despite the primary lung origin of
this tumor, there was no positive staining for thyroid
transcription factor-1. Staining with leukocyte common Lymphoepithelioma-like carcinoma must be considered
antigen highlighted the stromal lymphoid elements, and
while these cells were also seen in the tumor islets, the
tumor cells failed to stain. Epstein-Barr virus (EBV)
could not be demonstrated in the tumor cells, stromal
lymphocytes, or surrounding lung tissue, using anti-EBV
latent membrane protein (DAKO no897, Clones CS 1-4).
in the differential diagnosis of primary lung tumors,
particularly when extensive lymphocytic infiltrate is
present. As the tumor does not stain with thyroid
transcription factor-1 and cytokeratin-7, the possibility
that it represents metastasis from a primary elsewhere
needs to be excluded clinically. The role of adjuvant
therapy is not clear; however, chemotherapy and radio-
therapy have been employed with some success.3,8
DISCUSSION
Lymphoepithelioma-like carcinoma of lung is a rare tumor
that occurs more commonly in Asians, particularly
Chinese.1–3 A review of the literature indicated that
approximately 30 cases have been described so far.4 The
age of the patients varied from 8 to 78 years, with an
REFERENCES
1. Franklin WA. Diagnosis of lung cancer: pathology of
invasive and preinvasive neoplasia. Chest 2000;117:
S80–9.
2002, VOL. 10, N
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