A rare case of concurrent Wilms’ tumor in the left kidney and left ovary

Abstract

This report presents the first documented case of Wilms’ tumor concurrently affecting the kidney and ovary in a 5-year-old girl. The patient presented with an abdominal mass, initially suspected to be an ovarian germ cell tumor. An incidental left renal mass was identified during the radiologic evaluation. Histopathology confirmed Wilms’ tumor with unfavorable histology in both the kidney and ovary. Surgical interventions and adjuvant therapies resulted in a favorable response. This publication aims to underscore the rarity of such presentations and highlight the need for increased awareness and further research to improve management strategies for these challenging pediatric malignancies.

Highlights

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Concurrent Wilms’ tumors in left kidney and ovary, a first-time documented case.
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Extrarenal Wilms’ tumor diagnosis is challenging due to nonspecific imaging.
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Definitive diagnosis requires surgery and thorough histopathological assessment.
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Extrarenal Wilms’ tumors lack guidelines; more research is needed for improved care.

1 Introduction

Wilms’ tumor, a malignancy originating from nephrogenic blastema, is the most common renal tumor in children. However, its occurrence in extrarenal locations is exceedingly rare, with very few cases documented, particularly in the ovary. Despite histological similarities between extrarenal and renal Wilms’ tumor, diagnosing extrarenal Wilms’ tumor remains challenging due to nonspecific radiological characteristics. Ultrasonography, computed tomography (CT), and magnetic resonance imaging (MRI) are valuable diagnostic tools, yet they cannot provide definitive confirmation. Therefore, surgical intervention and histopathological examination are essential for an accurate diagnosis. We present an exceptionally rare case of Wilms’ tumor occurring concurrently in the left kidney and left ovary, characterized by unfavorable histology. The patient underwent surgical resection followed by adjuvant chemotherapy and radiotherapy, demonstrating a favorable response.

2 Case presentation

A 5-year-old girl presented to a tertiary care hospital with a two-month history of abdominal distension, pain, vomiting, and undocumented weight loss. There was no reported fever or additional gastrointestinal or urinary symptoms. Her family history was unremarkable. Physical examination revealed a fixed, firm, non-tender pelvic-abdominal mass extending above the umbilicus. Laboratory investigations showed normal hematological and tumor marker profiles (alpha-fetoprotein and beta-human chorionic gonadotropin), except for microcytic hypochromic anemia (hemoglobin level: 9.6 g/dL).

Abdominal and pelvic ultrasonography identified a well-circumscribed, heteroechoic mass occupying the majority of the abdomen and pelvis without adjacent organ invasion, along with a small benign-appearing lesion in the left kidney. Subsequent MRI confirmed a large, well-circumscribed, heterogeneously enhancing solid-cystic mass, likely arising from the left ovary , measuring 155 x 138 × 110 mm. There was no lymphadenopathy, and the mass was in contact with the liver, displacing the bowel loops, colon, bladder, and right kidney ( Fig. 1 ). Additionally, a well-defined 30 × 26 mm nodular lesion was detected at the upper pole of the left kidney, demonstrating post-contrast enhancement. Given the imaging findings and patient age, a provisional diagnosis of a left ovarian germ cell tumor was considered.

The patient underwent exploratory laparotomy, revealing a large lobulated intra-abdominal mass originating from the left ovary, whith no adherence to surrounding structures. Complete excision of the mass, along with left salpingo-oophorectomy, was performed. A fine-needle aspiration biopsy of the left renal lesion was also obtained. Macroscopically, the oophorectomy specimen weighed 1385 g and measured 200 × 140 mm, encapsulated by a thick whitish layer ( Fig. 2 ). Upon sectioning, the tumor was solid with central necrosis.

Histopathological examination demonstrated a mixture of blastemal, epithelial, and mesenchymal components. The mesenchymal component displayed fusiform cell proliferation arranged in intersecting bundles and diffuse sheets, with oval, hyperchromatic nuclei surrounded by pale eosinophilic cytoplasm ( Fig. 3 A). Immature blastemal elements were arranged in rosettes and clusters, exhibiting a high nucleocytoplasmic ratio, oval hyperchromatic nuclei, and frequent atypical mitotic figures ( Fig. 3 B). The epithelial component comprised moderately differentiated tubules and rare glomerular-like structures ( Fig. 3 C). Diffuse anaplasia was present, with no teratomatous elements. The renal biopsy revealed a multi-tissular malignant tumor involving renal parenchyma, consisting of blastemal, epithelial, and sparse stromal components. Surprisingly, the morphological appearance was consistent with a multi-tissular Wilms’ tumor with dual localization: ovarian, with diffuse anaplasia, and left renal involvement. The ovarian component was classified as high risk according to the revised International Society of Pediatric Oncology (SIOP) classification.