Primitive neuroectodermal tumor of the kidney confirmed byfluorescence in situ hybridization
SEIICHI KATO1, TOSHIMI TAKEUCHI1, TOMONARI ASANO1, YOSHIHITO BAN1,
TETSUYA YAMADA2, TADASHI HASEGAWA3 & NAOKI YAMAMOTO4
1Department of Urology and 2Central Laboratory, Gifu Municipal Hospital, Gifu-ken, Japan, 3Department of Surgical
Pathology, School of Medicine, Sapporo Medical University, Sapporo, Japan, and 4Department of Urology, Gifu University
Hospital, Gifu-ken, Japan
AbstractWe report a rare case of primitive neuroectodermal tumor of the kidney. The diagnosis was confirmed by theimmunohistochemical profile and fluorescence in situ hybridization in formalin-fixed, paraffin-embedded tissues. Thepatient received intensive chemoradiotherapy after radical surgery and remains alive without recurrence 1 year after initialpresentation.
Key Words: Primitive neuroectodermal tumor, kidney
We present a rare case of renal primitive neuroecto-
dermal tumor (PNET) which occurred in an adult.
The diagnosis was confirmed by the detection of a
Ewings sarcoma (EWS) rearrangement. The patient
received intensive chemoradiotherapy after radical
surgery and remains alive without recurrence 1 year
after initial presentation.
A 33-year-old female with no significant previous
medical history presented with right flank pain and
fever. Physical examination and routine laboratory
data were unremarkable. CT revealed a 8.0/8.0 cm2 mass in the inferior portion of the right
kidney. The mass exhibited an homogeneous mini-
mal enhancement with slightly higher attenuation
than the skeletal muscle (Figure 1). The patient
underwent a right radical nephrectomy. A periopera-
tive examination showed that there was no involve-
ment between the tumor and neighboring organs or
the renal vein.
Histological examination showed the tumor to
be composed of small cells with uniform round
nuclei and minimal cytoplasm forming many
HomerWright pseudorosettes (Figure 2A). Immu-nohistochemically, the tumor exhibited expression of
vimentin, neuron-specific enolase and CD99 but no
expression of desmin, alpha-smooth muscle actin,
Correspondence: Naoki Yamamoto, MD, Department of Urology, Gifu University Hospital, 1-1 Yanaido-Gifu-shi, Gifu-ken 501-1194, Japan. Fax: /58 2306339. E-mail: firstname.lastname@example.org
Figure 1. A CT scan revealed a solid tumor in the lower pole of
the right kidney. The tumor was slightly enhanced.
Scandinavian Journal of Urology and Nephrology, 2007; 41: 7576
(Received 7 March 2006; accepted 28 April 2006)
ISSN 0036-5599 print/ISSN 1651-2065 online # 2007 Taylor & FrancisDOI: 10.1080/00365590601135832
muscle-specific actin, pan-cytokeratin, epithelial
membrane antigen, S-100, CD34 or KIT/CD117
(Figure 2B). Interphase fluorescence in situ hybri-
dization (FISH) on routinely formalin-fixed, paraf-
fin-embedded tissues using a commercially available
EWSR1 (22q12) dual-color, break-apart rearrange-
ment probe indicated the presence of t(11;22),
confirming the diagnosis of PNET (Figure 2C).
The patient received irradiation to the renal bed in
conjunction with chemotherapy (cisplatinum and
etoposide). The patient remains alive without evi-
dence of recurrence 1 year after initial presentation.
EWS/PNET usually occurs in soft tissues but
occasionally arises within visceral organs. Recently,
EWS and PNET have been considered to be the
same disease entity according to the WHO classifi-
EWS/PNET often shows a morphologic overlap
with other small, blue, round-cell tumors, therefore
necessitating immunohistochemical analyses. In
some cases these may be difficult to interpret,
although expression of CD99 has been helpful in
confirming the diagnosis of EWS/PNET .
EWS/PNET is characterized by non-random
chromosomal translocations involving the EWS
gene. The translocation t(11;22)(q24;q12) is the
commonest and leads to formation of the EWSFLI1 fusion protein. In/90% of cases, EWS/
PNET has the t(11;22) chromosomal rearrange-
ment. Dual-color, break-apart interphase FISH
assays provide a highly specific and sensitive method
for identifying chromosome 22 rearrangements that
can definitively establish the diagnosis of PNET/
EWS. We could detect this rearrangement by means
of FISH using formalin-fixed, paraffin-embedded
tissues. These translocations are detectable not only
in this way but also with reverse transcriptase-
polymerase chain reaction (RT-PCR). However,
RT-PCR is less sensitive in formalin-fixed, paraffin-
embedded tissue than in frozen tissue. When only
paraffin blocks are available, FISH is the method of
Renal PNET is more aggressive than when PNET
occurs at other sites. The optimal therapeutic
management is unclear, but in general the tumor is
best treated with surgery followed by radiotherapy
and chemotherapy. The chemotherapeutic regimen
warrants continuing development and consideration
for use in future trials .
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P, Panagopoulos I, et al. Molecular cytogenetic characteriza-
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aggressive, poorly differentiated soft tissue sarcoma. Virchows
Figure 2. (A) The tumor was composed of small cells with uniform round nuclei and minimal cytoplasm forming many HomerWrightpseudorosettes. (B) The tumor cells showed diffuse and strong membranous staining for CD99. (C) The tumor cells showed one fused, one
orange and one green signal pattern (arrows) , indicating a rearrangement in one copy of the EWSR1 region.
76 S. Kato et al.