Adult Uterine Wilm’s Tumor Miss-interpreted as "Carcinosarcoma," a case report

Background: Wilm’s tumor (WT) is a common renal malignancy in children. Adult extrarenal WT involving the uterus is extremely rare. Herein, we report a rare case of uterine WT in an old woman that was primarily diagnosed as carcinosarcoma. Case presentation A 63-year-old woman presented with abdominal pain and radiologic evidence of pelvic mass originating from the uterus, suggestive of sarcoma. In addition to the serum elevation of Cancer Antigen 125 (CA125), Human Epididymis Protein 4 (HE4), and Cancer Antigen 19-9 (CA19-9), Alpha Fetoprotein (AFP) was also increased. Pathologic examination of total hysterectomy, bilateral salpingo-oophrectomy, and omentectomy specimens revealed a large uterine mass with a serosal surface and an omental invasion. On microscopic examination, mixed epithelial and mesenchymal components were seen, so the initial diagnosis was carcinosarcoma. On the second opinion, triphasic components of papillary, primitive tubules and glomeruloid structures, mesenchymal, and blastemal elements were identified. The IHC study revealed positive reactions of the tumor cells for WT1, CKAE 1/AE3 , EMA, Glypican-3, and CD56 in all components. P53 showed normal expression. GATA3, ER, PR, and CD10 were negative. The final diagnosis was changed to WT. Conclusion: Uterine Wilm’s tumor is an extremely rare malignancy that could be associated with elevated serum AFP. The diagnosis and treatment of these rare tumors are challenging for both pathologists and clinicians.