Adult Extrarenal Wilms’ Tumor Mimicking Mixed Epit

Authors: Kyuichi Kadota Reiji Haba Yoshio Kushida Naomi Katsuki Toshitetsu Hayashi Yumi Miyai Kenji Bando Rikiya Taoka Yoshiyuki Kakehi

Publish Date: 2009/04/24

Volume: 15, Issue: 4, Pages: 665-

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Abstract

We report an extremely rare case of adult extrarenal Wilms’ tumor WT in a 52yearold woman who presented with fever and abdominal distension Computed tomography revealed a welldefined mass lesion measuring 150 cm in the right retroperitoneum and that was in contact with the right kidney The mass and kidney were surgically removed Grossly the mass was welldefined measuring 163 × 110 × 98 cm and appearing grayishwhite in color The border between the mass and the kidney was welldefined Histologically the tumor showed a triphasic pattern consisting of stromal epithelial and blastemal components The stromal component was predominant in the tumor and consisted both of spindle cells and smooth muscle cells The epithelial component showed a mature glandular structure Immunohistochemically the stromal component was positive for vimentin smooth muscle actin and desmin The blastemal component was positive for vimentin while the epithelial component was positive for cytokeratin CK 18 CK7 and vimentin WT1 was negative in the all three components and the Ki67 proliferation index was low The postoperative histopathological diagnosis indicated extrarenal WT arising in the retroperitoneum Although not treated by either chemotherapy or radiation therapy she was free from disease recurrence for 30 months after surgery To the best of our knowledge this report is only the fourth case of adult extrarenal WT arising in the retroperitoneum Furthermore the present case showed predominant smooth muscle differentiation and a mature glandular structure mimicking a mixed epithelial and stromal tumor

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