Year : 2004 | Volume
: 14 | Issue : 2 | Page : 147--148
Extrarenal wilm's tumour : A case report
BN Lakhkar, KV Rajgopal, CM Shetty, KR Avinash
Department of Radio Diagnosis, and Imaging, Kasturba Medical College and Hospital Manipal-576104, India
B N Lakhkar
Department of Radio Diagnosis, and Imaging, Kasturba Medical College and Hospital Manipal-576104
|How to cite this article:|
Lakhkar B N, Rajgopal K V, Shetty C M, Avinash K R. Extrarenal wilm's tumour : A case report.Indian J Radiol Imaging 2004;14:147-148
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Lakhkar B N, Rajgopal K V, Shetty C M, Avinash K R. Extrarenal wilm's tumour : A case report. Indian J Radiol Imaging [serial online] 2004 [cited 2020 Jun 5 ];14:147-148
Available from: http://www.ijri.org/text.asp?2004/14/2/147/28571
Wilms' tumour is one of the most common tumours of childhood as well as the most common malignant tumour of the genitourinary tract in children.The majority of these tumours arise from the kidney .Very few cases of Wilms' tumour arising outside the kidney have been reported .Till date only about 100 well documented cases of Extrarenal Wilms' tumour have been reported .We report a well proven case of an Extrarenal Wilms' tumour arising in the retroperitoneum.
A two year old boy was admitted in the pediatric department with complains of vomiting and abdominal pain of one week duration. There were no urinary complaints .The child was normotensive .The child was not toxic and the general condition was normal.
On examination fullness was noted in the right iliac fossa and lumbar region. A nonmobile mass of approximate size 4 X 6 cms was palpable with smooth surface and well defined borders in the right iliac fossa. The hematological parameters and routine investigation reports were normal.
Plain radiograph was unremarkable. Abdominal sonography demonstrated a mixed echogenic mass in the right retroperitoneal area abutting the lower pole of right kidney.
CT scan of the abdomen showed a well defined heterogeneously enhancing soft tissue density mass with areas of necrosis in the right retroperitoneum anterior and inferior to the right kidney. Both kidneys were normal. The mass was seen abutting the psoas muscle but the fat plane with the kidney was intact. The mass was seen displacing the small bowel loops anteriorly and laterally and the pancreas superiorly. No evidence of calcification was seen in the lesion[Figure 1] & [Figure 2]. FNAC from the lesion revealed Wilms' tumour.
The child was operated under general anaesthesia by a supraumbilical transverse incision.
A 10 X 12 cms well encapsulated mass arising from the retroperitoneum with bosselated surface and multiple dilated veins on the surface was noticed. The right ureter was stretched over the tumour. No evidence of retroperitoneal nodes or venous extension of the tumour was noted. The tumour was seen separate from the kidney and the entire tumour was removed.
On histopathology, the fleshy tumour was firm to hard in consistency. Microscopy revealed Extrarenal triphasic nephroblastoma. There was evidence of epithelial components(tubular differentiation in the form of small and large tubules lined by cuboidal epithelium and many abortive glomeruli),stromal components (small fibrillary glial like stroma and loose fibrous stroma composed of spindle cells) and blastemal components (in the form of sheets and nodules with hyperchromatic nuclei). Abundant mitosis were seen with areas of micro necrosis [Figure 3].No focal anaplasia was noted.
Post operatively the child was started on chemotherapy consisting of dactinomycin, doxorubicin and vincristine with external radiotherapy. The child completed 14 weeks of chemotherapy (Total course of 24 weeks) and is responding well to treatment.
Extrarenal Wilms' tumour refers to a tumour that is not connected with the kidney, but bears a close resemblance to Wilms' tumour while both kidneys are normal. Wilms' tumour originating outside the kidney is extremely rare. A diagnosis must exclude a primary tumour in kidney with secondary metastases .In case of juxtarenal Wilms' tumour, a supernumerary kidney must be ruled out. Reported location of Extrarenal Wilms' include inguinal region, endocervix, uterus, epididymis, ovotestis and any place along the retroperitoneum. It is believed that origin of Extrarenal Wilms' tumour parallels that of intrarenal Wilms' tumour and arises from heterotopic metanephric blastema.Another possible mechanism involves Cohnheim's theory in which cells with persistent embryonal potential undergo malignant transformation.The clinical presentation varies with site of tumour and it has been almost always difficult to diagnose it preoperatively. The staging of National Wilms' Tumour Study (NWTS) has been applied to cases of Extrarenal Wilms' Tumour as there is no accepted staging of Extrarenal Wilms' Tumour [Table 1].
The recommended management of true Extrarenal Wilms' includes a thorough staging, detailed pathologic classification, post operative chemotherapy and radiotherapy, fashioned after an accepted program for a similarly staged intrarenal Wilms' tumour.
The imaging presentation of Extrarenal Wilms' tumour is similar to intrarenal Wilms' tumour. The prognosis of Extrarenal Wilms' is comparable to the prognosis of intrarenal Wilms' tumour in NWTS .
Teratomas containing nephroblastic tissue most likely represent a different embryologic origin and therefore should be classified separately. When extrarenal nephroblastic tissue is encountered, the pathological specimen should be thoroughly examined for teratomatous elements with thorough histologic examination of whole tumour.
In conclusion, the imaging appearance of Extrarenal Wilms' Tumour is similar to intrarenal Wilms' Tumour. The diagnosis of Extrarenal Wilms' tumour has to be done after ruling out an extension from the intrarenal Wilms' tumour or a metastatic lesion. However the final diagnosis is established by histopathology.
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