DOI:10.2214/AJR.04.1631
AJR 2005; 185:1347-1349
© American Roentgen Ray Society
Desmoplastic Small Round Cell Tumor of the Kidney in a Pediatric Patient: Sonographic and Multiphase CT Findings
Alexia M. Egloff1,
Edward Y. Lee1,
Johanne E. Dillon1 and
Michael J. Callahan1
1 All authors: Department of Radiology, Children's Hospital Boston and Harvard
Medical School, 300 Longwood Ave., Boston, MA 02115.
Received October 19, 2004;
accepted after revision November 19, 2004.
Address correspondence to E. Y. Lee
(Edward.Lee{at}childrens.harvard.edu).
Introduction
Desmoplastic small round cell tumor (DSRCT) is a rare, high-grade,
malignant neoplasm usually seen in children, adolescents, and young adults,
where it has an aggressive clinical course
[1-5].
It is typically an intraabdominal tumor associated with serosal surfaces and
unusual locations (e.g., serosal surfaces of the pleura, scrotum, and ovary)
have been reported [1,
2,
6,
7]. To our knowledge, a single
case of DSRCT of the kidney was recently reported in an adult male patient
[6]. However, DSRCT of the
kidney in pediatric patients and its sonographic and CT characteristics in
pediatric and adult populations have not been reported. We present a case of
DSRCT of the kidney in a 6-year-old girl who was evaluated with renal
sonography and multiphase CT.
Case Report
A 6-year-old girl with no significant medical history presented to an
outside hospital with gross hematuria after abdominal trauma. Physical
examination was unremarkable except for mild left flank tenderness on deep
palpation. Laboratory studies were within normal limits except for microscopic
blood on urinalysis. The patient underwent sonographic examination of the
abdomen, which showed an approximately 5-cm well-circumscribed heterogeneous
mass in the midportion of the left kidney, accompanied by small foci of
punctate calcifications (Fig.
1A). Compared with the adjacent renal cortex, the mass had no
increased blood flow, and no extension of tumor into the left renal vein was
present.
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Fig. 1A —Six-year-old girl with hematuria and left flank pain after
trauma. Renal sonogram shows well-circumscribed, heterogenous mass (white
arrows) with associated calcifications in midportion of left kidney
(black arrows).
|
|
The patient was subsequently referred to our hospital and underwent a
multiphase CT examination of the abdomen and pelvis on a helical scanner. An
unenhanced CT examination of the abdomen and pelvis was first performed. The
patient then received 2 mL/kg of nonionic IV contrast material ([ioversol]
Optiray 320, Mallinckrodt) at an injection rate of 1.5 mL/sec. Postcontrast
images were obtained at 30 sec (corticomedullary phase) and 100 sec
(nephrographic phase) after the initiation of the contrast medium
injection.
CT examination showed an ovoid hypovascular mass in the midportion of the
left kidney measuring 4.5 cm in diameter. Although the margins of the mass
were not clearly defined on the unenhanced images
(Fig. 1B), the mass was well
demarcated during the corticomedullary and nephrographic phases of the
enhanced examination (Figs. 1C
and 1D). On the unenhanced
images, the mass was slightly hyperdense compared with the normal renal
parenchyma and showed multiple foci of punctate calcifications. On the
enhanced portions of the study, the mass was hypodense compared with the
adjacent normally enhancing renal parenchyma. No extension of the mass into
the perinephric fat, involvement of the left renal vein, and associated
lymphadenopathy were seen. Neither a chest CT nor bone scintigraphy showed
evidence of metastatic disease.
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Fig. 1B —Six-year-old girl with hematuria and left flank pain after
trauma. Multiple punctate calcifications are seen in midportion of left kidney
on precontrast CT image. Margins are indistinct.
|
|
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Fig. 1C —Six-year-old girl with hematuria and left flank pain after
trauma. Well-defined, low-attenuation mass (arrow) measuring
approximately 4.5 cm in diameter is conspicuous during corticomedullary phase
of renal parenchymal enhancement. Several punctate calcifications are
noted.
|
|
The patient subsequently underwent a left radical nephrectomy followed by
adjuvant chemotherapy. On gross pathologic examination, the mass was
yellow-tan, well defined, and measured 4 x 4 x 3 cm. The tumor
involved the cortex, medulla, and renal sinus. Multifocal calcifications and
foci of necrosis were seen. Although the mass was noted to abut the renal
capsule, no capsular penetration, invasion of the perirenal fat, and lymphatic
spread were seen, consistent with stage I. Immunohistochemistry was positive
for Wilms' tumor suppressor gene (WT1), desmin, smooth muscle actin, and CAM
5.2, and negative for synaptophysin, CD99, S-100, NB84, epithelioid membrane
antigen, and myogenin, consistent with DSRCT. Cytogenetic analysis showed a
reciprocal translocation involving chromosomes 11 and 22, and reverse
transcriptase-polymerase chain reaction (RT-PCR) was positive for fusion of
the Ewing's sarcoma gene (EWS1) to WT1, also consistent with DSRCT.
The patient's postoperative course was uneventful. Nine months after
surgery, while receiving adjuvant chemotherapy, the patient remained
asymptomatic and clinically stable, with no evidence of tumor recurrence.
Discussion
DSCRT is a rare, aggressive, and malignant neoplasm typically seen in
children, adolescents, and young adults, where it has a 4-5:1 male
predilection [1,
8]. The abdominal cavity's
serosal surfaces are the most common location of the tumor. However, more
unusual primary lesions involving the serosal surfaces of the pleura, scrotum,
and ovary have been described. Far less common are extraserosal lesions, and
in fact, only one case each of DSRCT of the kidney, bone and soft tissues of
the hand, parotid, sinonasal tissues, intracranial tissues, and scalp soft
tissues have been reported [6,
7].
The clinical symptoms of patients with DSRCT are usually nonspecific,
including abdominal pain and weight loss. Metastases are often present at the
time of diagnosis; the most common sites are the liver, lung, and regional
lymph nodes [1,
8]. In the setting of
metastatic disease, prognosis is poor since there is usually an unfavorable
response to surgical resection and chemotherapy
[1,
3,
8].
Macroscopically, DSRCT typically forms lobulated masses of varying size and
color (e.g., white, tan, yellow, gray) within the peritoneal cavity.
Intraperitoneal seeding is not rare
[5,
7]. Histologic analysis has
shown nests of small round cells circumscribed by dense fibrous connective
tissue
[1-4,
7]. The cytogenetic
characteristics of DSRCT are unique, showing EWS1-WT1 fusion by RT-PCR and
Southern blotting, consistent with the reciprocal translocation
[t(11;22)(p13;q12] present in nearly every DSRCT and specific for DSCRT
[2,
6,
7]. A similar fusion between
EWS and WT1 is seen in Ewing's sarcoma and peripheral primitive
neuroectodermal tumor. However, in these tumors, the long arm of chromosome 11
is involved, while DSRCT affects the short arm
[2].
On sonography, peritoneal DSRCT may be a single mass or multiple masses
that are well-defined and hypoechoic and lack a definite organ of origin
[1,
3,
5-8].
Heterogeneity within the tumor due to hemorrhage or necrosis may be seen on
both CT and sonography [6].
Small foci of punctate calcification have also been described in patients with
abdominal DSRCT. In patients with advanced disease, lymphadenopathy, ascites,
and liver metastases may be present on CT
[5,
8]. Findings secondary to
obstruction by tumor, such as hydronephrosis or bowel obstruction, may also be
present [1,
5,
7].
The sonographic and CT characteristics of the renal DSRCT in our patient
were similar to the imaging findings of patients with the more common
abdominal serosal lesions [4,
5]. Both sonography and CT
examinations showed a hypovascular, heterogeneous, and well-circumscribed
mass, while several foci of punctate calcifications were especially evident on
CT.
In contrast with previously published reports of patients with
genitourinary DSRCT, in which nearly all patients were men, our patient was a
woman. Although the kidney was the sole site of involvement in the one adult
man reported with renal DSCRT, tumor was found in the ovaries and ureters but
the kidneys were spared in the two women with previously described
genitourinary DSRCT [3].
Detailed gross descriptions and imaging findings are not available in the one
adult patient with renal DSRCT. However, this patient's tumor measured 5 cm in
diameter and showed low attenuation on CT, similar to our patient's gross
pathologic and CT findings
[6].
Although we report findings in only one pediatric patient, we believe that
punctate calcifications within DSRCT may be helpful in differentiating this
tumor from other more common pediatric renal malignancies, including Wilms'
tumor, clear cell sarcoma, and rhabdoid tumor. Clear cell sarcoma and rhabdoid
tumor do not contain calcifications. Although 5-15% of Wilms' tumors in
children may have calcifications, these calcifications are usually curvilinear
rather than punctate. Approximately one quarter of pediatric renal cell
carcinomas contain calcifications. However, renal cell carcinomas are
hypervascular masses that are usually seen in children over 10 years old,
unlike the hypovascular DSRCT in our 6-year-old patient.
In summary, we report the sonographic and CT findings in a pediatric
patient with an early presentation of renal DSRCT. Although rare, DSRCT should
be considered in pediatric patients with characteristic hypovascular,
well-circumscribed renal masses with associated punctate calcifications.
References
- Baltogiannis N, Mavridis G, Keramidas D. Intraabdominal
desmoplastic small round cell tumor: report of two cases in paediatric
patients. Eur J Pediatr Surg 2002;12
: 333-336[Medline]
- Crapanzano JP, Cardillo M, Lin O, Zakowski MF. Cytology of
desmoplastic small round cell tumor. Cancer2002; 96:21
-31[Medline]
- Furman J, Murphy WM, Wajsman Z, Berry AD 3rd. Urogenital
involvement by desmoplastic small round-cell tumor. J
Urol 1997; 158:1506
-1509[Medline]
- Kim JH, Goo HW, Yoon CH. Intra-abdominal desmoplastic small round
cell tumor: multiphase CT findings in two children. Pediatr
Radiol 2003; 33:418
-421[Medline]
- Pickhardt PJ, Fisher AJ, Balfe DM, et al. Desmoplastic small round
cell tumor of the abdomen: radiologic-histopathologic correlation.
Radiology 1999;210
: 633-638[Abstract/Free Full Text]
- Su MC, Jeng YM, Chu YCH. Desmoplastic small round cell tumor of the
kidney. Am J Surg Pathol 2004;28
: 1379-1383[Medline]
- Lae ME, Roche PC, Jin L, et al. Desmoplastic small round cell
tumor. Am J Surg Pathol 2002;26
: 823-835[CrossRef][Medline]
- Sharma S, Vikram NK Thulkar S, Goel S. Case of the season.
Semin Roentgenol 2001;36
: 3-5[Medline]
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Introduction
Case Report
