Bilateral Extrarenal Inguinal Nephroblastomatosis - A Rare Event

Objective: To report an unusual case of extrarenal nephroblastomatosis involving bilateral inguinal regions. Background: Nephroblastomatosis and nephrogenic rests are usually found in neonatal kidneys sub-clinically or associated with Wilms tumor. Extrarenal occurrence of this immature renal tissue is reported in literature as an incidental finding seen in inguinal canal, retroperitonium, along with a teratoma and sometimes associated with development of Wilms tumor. Involvement of bilateral inguinal regions is quite unusual and is not yet reported. Proper histological diagnosis is mandatory to distinguish them from Wilms tumor. After diagnosis a conservative therapeutic approach and regular follow-up is all that is required in these cases. Case Presentation: A 5 months old female baby presented with bilateral inguinal swellings since birth. Initially FNAC was performed, a diagnosis of small round blue cell tumor was made and excision was advised. On H&E slides of excised specimen a diagnosis of bilateral extrarenal nephroblastomatosis was made and a close follow-up was advised. Conclusion: Bilateral extrarenal nephroblastomatosis is a rare event. It has a close association with Wilms tumor. Considering the risk a thorough histological examination with proper diagnosis is required to plan appropriate treatment options for the patient. Regular follow-up for early detection of malignant transformation is also mandatory.