Journal of Pediatric Surgery (2006) 41, 1759 – 1763
Teratoid Wilms’ tumor: a case report with literature review Mikihiro Inouea, Keiichi Uchidaa, Otake Koheia, Yuji Nashidab, Takao Deguchib, Yoshihiro Komadab, Masato Kusunokia,* a
Department of Gastrointestinal and Pediatric Surgery, Mie University Graduate School of Medicine, Tsu, Mie 514-8507, Japan b Department of Pediatrics, Mie University Graduate School of Medicine, Tsu, Mie 514-8507, Japan Index words: Teratoid Wilms’ tumor; Nephroblastoma
Abstract Teratoid Wilms’ tumor is an unusual histologic variant of nephroblastoma in which the heterologous tissue predominates. The treatment for this tumor has not been established because of its rarity and varying tumor components. The authors report a case of localized teratoid Wilms’ tumor in a 4-month-old female infant successfully treated with nephrectomy only. The tumor originated from the right kidney with multiple cysts and calcifications; renal teratoma was suspected preoperatively, and the operation was performed. The tumor was excised completely, and the specimen weighed 340 g. Histopathologic examination showed that various teratoid elements occupied most of the tumor with sparse islands of triphasic nephroblastoma, which was consistent with teratoid Wilms’ tumor. Anaplastic elements, tumor capsule invasion, renal sinus soft tissue invasion, or tumors in intrarenal vessels were not observed. The patient was disease free for 3 years after surgery without receiving chemotherapy. We selected this therapeutic approach because of the chemoresistance of this tumor and the excellent prognosis in small (b550 g) stage I/favorable-histology classical Wilms’ tumor diagnosed at less than 24 months of age. Therefore, nephrectomy alone may be an acceptable treatment of this stage of tumor in patients with teratoid Wilms’ tumor. D 2006 Elsevier Inc. All rights reserved.
Teratoid Wilms’ tumor, a rare variant of nephroblastoma, has a predominance of teratoid elements consisting of more than 50% of the tumor . To date, 15 cases of teratoid Wilms’ tumor have been reported in the literature [1-12]. All patients were operated on with combination chemotherapy, and some patients also received radiotherapy, which is the current therapeutic strategy for classical Wilms’ tumor. Some problems such as resistance to chemo- and radiotherapy result from the mature heterologous components [1-4].
* Corresponding author. Tel.: +81 59 232 1111x5645; fax: +81 59 232 6968. E-mail address: [email protected]
(M. Kusunoki). 0022-3468/$ – see front matter D 2006 Elsevier Inc. All rights reserved. doi:10.1016/j.jpedsurg.2006.05.045
Treatment of teratoid Wilms’ tumor has not yet been established. We describe here an infant with unilateral localized teratoid Wilms’ tumor who was successfully treated with nephrectomy only, and we have also reviewed all cases reported in the literature.
1. Case report A 4-month-old boy had a palpable mass on the right side of the abdomen and was admitted for evaluation and management to Mie University Hospital. He was an otherwise healthy child with no remarkable medical history. There was no episode of hematuria before admission.
Fig. 1 Abdominal x-ray showing localized calcification in the right side of the abdomen.
Physical examination revealed an elastic hard mass without tenderness at the right flank of the abdomen. The mass was palpable 8 cm below the right costal margin. A noteworthy laboratory finding upon admission was a human chorionic gonadotropin level of 4.5 ng/mL (normal, b0.5 ng/mL), and a neuron-specific enolase level of 41 ng/mL (normal, b10 ng/mL). Serum levels of ferritin, alpha-fetoprotein, vanillylmandelic acid, and homovanillic acid were within normal limits. Abdominal radiography showed scattered calcification in the mass (Fig. 1). Transabdominal ultrasonography and abdominal computed tomography (CT) revealed a large multicystic mass with multiple calcifications occupying the right kidney. CT scan with intravenous
M. Inoue et al. contrast showed that only the encased renal parenchyma was enhanced (Fig. 2). Chest and brain CT findings were normal. All these findings suggested that renal teratoma was the most probable diagnosis, and thus, right nephrectomy was performed. At the operation, we observed that most of the right kidney was replaced by the tumor, which was enveloped by a smooth, glistening capsule. The inferior vena cava was compressed by the tumor, but vascular invasion was not observed. Some enlarged paraaortic and precaval lymph nodes were also resected. The nephrectomy specimen weighed 340 g and measured 8 7 5 cm. Histopathologically, the tumor consisted primarily of various teratoid elements such as stratified squamous epithelium, columnar epithelium, pigment cells, mature adipose tissue, and cartilage or bone tissue. Tendency toward organogenesis was not shown in these tissues. There were also occasional islands of triphasic nephroblastoma with blastematous, epithelial, and stromal components (Fig. 3). Anaplastic elements, tumor capsule invasion, renal sinus soft tissue invasion, or tumors in intrarenal vessels were not observed. There was no lymph node metastasis. These findings were compatible with those of teratoid Wilms’ tumor at stage I. The postoperative course was uneventful, and the child was discharged from hospital without receiving chemotherapy. Preoperatively elevated serum levels of the tumor markers had fallen to a normal range within 8 weeks after surgery. The patient is alive and free of disease 3 years after surgery.
2. Discussion Wilms’ tumor is an embryonic tumor with a triphasic histologic pattern represented by blastemal, stromal, and epithelial components . It is recognized that nephroblastoma can include heterologous elements in addition to
Fig. 2 CT before operation. A, Noncontrasted study shows the multicystic tumor originating from the right kidney with multiple calcification. B, Contrasted study reveals enhancement of the encased renal parenchyma only.
Teratoid Wilms’ tumor: a case report with literature review
Fig. 3 The nephrectomy specimen showing heterologous elements including bone tissue (A), glial cells, adipose tissue (B), and pigment cells (C) with very sparse islands of renal blastema (D). H&E, original magnification 200 (A, B), 100 (C), 400 (D).
these components [5,13]. In 1984, the term teratoid Wilms’ tumor was coined by Variend et al , and Fernandes et al  defined a tumor that contains heterologous elements comprising more than 50% of the tumor. This rare variant of Wilms’ tumor has been reported in 16 cases in the literature including our case, and the clinical features of these reported cases are described in Table 1 [1-12]. Twelve of 16 cases were diagnosed in 2- to 4-year-olds, and 6 bilateral cases were observed. Although 9 cases received preoperative chemotherapy for the treatment of Wilms’ tumor, all except 1 case was resistant to the therapy. This resistance to treatment may be because of the mature, differentiated heterologous elements that make up a large part of the tumor [1-4]. Teratoid Wilms’ tumor is not usually aggressive and the prognosis is comparatively good if the tumor is excised. Three patients died, of which 2 had bilateral and 1 had paraaortic and mesenteric lymph node metastases at diagnosis [2,7]. In all of these patients, the tumor was not completely resected at the operation. For these reasons, surgery seems to be the best treatment if the diagnosis is made preoperatively and the tumor is resectable [3,4]. Concerning postoperative therapy, in all of the cases of teratoid Wilms’ tumor, except our case, the patients received chemotherapy regardless of tumor stage, size, age at
diagnosis, and histology. In our case, the patient was less than 24 months of age with a stage I/FH tumor weighing less than 550 g. This type of Wilms’ tumor shows excellent prognosis because it is highly correlated with the absence of adverse prognostic factors such as the presence of an inflammatory pseudocapsule, renal sinus soft tissue invasion, tumor capsule invasion, and tumors in intrarenal vessels . In 1979, Green and Jaffe  hypothesized that nephrectomy only might be an appropriate therapy for patients with a stage I/FH tumor. This hypothesis is supported by several investigations [16,17]. On the other hand, in 2001, the National Wilms’ Tumor Study (NWTS) Group reported that the 2-year relapse-free survival rate of children younger than 24 months with small, FH Wilms’ tumor treated with nephrectomy only was 86.5%. These results were slightly less successful than that of children treated in previous NWTS studies with nephrectomy and adjuvant chemotherapy where the 2-year overall survival rate was 100% . This study also showed diffuse blastema in the tumor component and incomplete evaluation of renal sinus soft tissue extension, which were associated with increased relapse risk. These results indicate that nephrectomy only should not be the standard therapy for children less than 24 months of age with stage I/FH Wilms’ tumor;
Cases of teratoid Wilms’ tumor
Age, sex (reported year)
Origin of the tumor
Metastasis or invasion at diagnosis
Complete tumor resection
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16
3 y, f (1984) 2 y, m (1988) 2 y, m (1988) 2 y, m (1988) 1 y, f (1991) 2 y, m (1992) 9 mo, (1992) 3 y, f (1994) 3 y, f (1994) 3 y, f (1996) 7 y, m (1998) 2 y, m (2000) 2 y, m (2000) 4 y, f (2003) 4 y, f (2003) 4 mo, m (our case)
Bi Bi Bi Bi Rt Lt Rt Rt Bi Lt Rt-UPS Bi Rt Lt Rt Rt
No No No No No No No No No LN, CI No No LN No No No
5 5 5 5 1 1 1 1 5 3
Unknown Unknown Unknown Unknown 320 g 1005 g 840 g 650 g Unknown 1036 g 111 g Unknown Unknown Unknown 3200 g 340 g
Yes (Effective) Yes (Not Effective) No Yes (Not Effective) Yes (Not Effective) No No Yes (Nor Effective) Yes (Not Effective) Yes (Not Effective) No Yes (Not Effective) No Unknown Yes (Not Effective) No
Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes
Yes No Yes No Yes Yes Yes Yes No No Yes Yes No Yes Yes Yes
Unknown Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Unknown Yes Unknown Yes No
No Yes No Yes No No No No Yes Yes No No Yes Unknown Yes No
Unknown No Yes (7 y 6 mo, DF) Yes (2 y 2 mo, DF) Yes (2 y, DF) Yes (4 y, DF) Yes (1 y, DF) Yes (1 y 11 mo, DF) No Yes (1 y 5 mo) Yes (1 y 6 mo, DF) Unknown No Unknown Yes (2 y 8 mo, DF) Yes (3 y, DF)
% of treatment option Effective rate or survival rate (%)
5 3 1 2 1
Bi indicates bilateral kidneys; DF, disease free; Rt, right kidney; Lt, left kidney; LN, lymph node metastasis; CI, caval invasion; and Rt-UPS, right ureteropelvic structure.
M. Inoue et al.
Teratoid Wilms’ tumor: a case report with literature review however, this therapeutic strategy should be available for selected children in this group. In our case, the tumor contained only occasional areas of conventional Wilms’ tumor without anaplastic elements, tumor capsule invasion, renal sinus soft tissue invasion, or tumors in intrarenal vessels. We determined that nephrectomy only would be an adequate treatment for our patient considering the results of histology and the risks of combination chemotherapy in this group of young children. On the other hand, the other patient who belongs to this group had received adjuvant chemotherapy, as reported in the literature. This therapeutic approach resulted in a good outcome in our case. The treatment of teratoid Wilms’ tumor has not yet been established because of its rarity and varying tumor components. To determine the optimal treatment, consideration must be given to the clinical and histopathologic characteristics of the disease. Although treatment with postsurgical chemotherapy for the advanced or bilateral teratoid Wilms’ tumor is an acceptable option, the therapy for stage I completely resected teratoid Wilms’ tumor without poor prognostic factors is open to further investigation on whether chemotherapy is required, particularly in a very sparse blastemal component case.
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