Indian Journal of Medical Sciences Medknow Publications on behalf of Indian Journal of Medical Sciences Trust ISSN: 0019-5359 EISSN: 1998-3654 Vol. 58, Num. 2, 2004, pp. 72-73

Indian Journal of Medical Science Vol. 58 No. 2, February 2004 , pp. 72-73

Letter to Editor

Wilms' tumor arising in a horseshoe kidney

Sashidhar V Yeluri, Dipesh D Duttaroy, Pranav Ghodgaonkar, Siddharth Karanth

Department of Surgery, Sir Sayajirao General Hospital and Medical College, Baroda - 390001, India.
E-mail: y.sashidhar@lycos.com

Code Number: ms04011

Sir,

Wilms tumor [WT] is the commonest malignancy in children. It is associated with multiple congenital anomalies and malformations, commonest being aniridia, hemi hypertrophy and genitourinary anomalies. Although the overall incidence of malignancies arising in a HSK is not increased, the risk of developing WT increases many folds compared to general population. The association of extrarenal WT¹ and renal carcinoid² tumor with HSK is now known.

A two and a half year old male child was brought with history of progressively enlarging abdominal lump for 2 months. Examination revealed a large firm mass predominantly in the right lumbar and hypochondrium. Intravenous pyelography [IVP] was not diagnostic of HSK. CT scan confirmed a HSK with an isthmus at the lower pole and a mass arising from the non functioning right kidney. Fine needle aspiration cytology [FNAC] showed WT. A right radical nephrectomy with isthmusectomy was performed. Histology confirmed stage 1 multilocular cyst variant. Patient was given Actinomycin D and Vincristine for 24 weeks with an uneventful post operative recovery.

HSK was not recognized preoperatively in almost a third of patients in the National Wilms tumor study.³ Though CT scan is a reliable investigation, the position of HSK in the midline overlying the spine makes diagnosis on IVP and angiography difficult. WT in a HSK poses an operative challenge to the surgeon. HSK's are normally situated lower than normal kidneys and have an anomalous blood supply. Generally 4-6 renal arteries supply the HSK; 2 to each hilum and 1-2 to the isthmus. The blood supply to the hilum of the kidney may arise from the renal artery, directly from the aorta, the inferior mesenteric artery or the iliac artery.⁴ Preoperative arteriography can thus facilitate surgery. Both ureters take an unusual course due to the abnormal position of the renal pelvis which predisposes them to inadvertent operative injury. The presence of blastemal cells with epithelial cells and stroma allows a diagnosis of WT by FNAC. If the tumor involves one kidney in a HSK, the functional isthmus has to be resected along with the tumor, lest a urinary fistula result. If the tumor arises from the isthmus, isthmusectomy with bilateral lower pole heminephrectomy is needed.

Owing to the position of HSK overlying the spine, it is readily accessible to physical examination. We emphasize a strong clinical suspicion and regular periodic abdominal examination to identify early stage WT in a child with HSK.

REFERENCES

1. Kapur VK, Sakalkale RP, Samuel KV, Meisheri IV, Bhagwat AD, Ramprasad A, Waingankar VS. Association of extrarenal Wilms' tumor with a horseshoe kidney. J Pediatr Surg 1998;33: 935-7.
2. Krishnan B, Truong LD, Saleh G, Sirbasku DM, Slawin KM. Horseshoe kidney is associated with an increased relative risk of primary renal carcinoid tumor. J Urol 1997;157:2059-66.
3. Neville H, Ritchey ML, Shamberger RC, Haase G, Perlman S, Yoshioka T. The occurrence of Wilms tumor in horseshoe kidneys: a report from the National Wilms Tumor Study Group (NWTSG). J Pediatr Surg 2002;37:1134-7.
4. Lal A, Marwaha RK, Narsimhan KL, Yadav K. Wilms' tumor arising in a horseshoe kidney. Indian Pediatr 1995;32:689-92.

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