BACKGROUND: Wilms tumor (WT), also known as nephroblastoma, is rare in adults, accounting for merely 3% of all nephroblastomas or 0.2 cases per million individuals. Extrarenal Wilms tumor (ERWT) emerges outside the renal boundaries and comprises 0.5 to 1% of all WT cases, with even rarer incidences in adults. Oncogenic mutations associated with ectopic nephrogenic rests (NR) may contribute to ERWT development. Diagnosis involves surgical resection and pathology examination. Due to scarce cases, adults often rely on pediatric guidelines. We thoroughly searched PubMed, Scopus, and Web of Science databases to establish our case\'s uniqueness. To the best of our knowledge, this is the first documented incidence of extrarenal Wilms tumor within the spinal canal in the adult population.
METHODS: A 22-year-old woman with a history of congenital lipo-myelomeningocele surgery as an infant presented with a 6-month history of back pain. This pain gradually resulted in limb weakness, paraparesis, and loss of bladder and bowel control. An MRI showed a 6 × 5 × 3 cm spinal canal mass at the L4-S1 level. Consequently, a laminectomy was performed at the L4-L5 level to remove the intramedullary tumor. Post-surgery histopathology and immunohistochemistry confirmed the tumor as ERWT with favorable histology without any teratomatous component.
CONCLUSIONS: This report underscores the rarity of extrarenal Wilms tumor (ERWT) in adults, challenging conventional assumptions about its typical age of occurrence. It emphasizes the importance of clinical awareness regarding such uncommon cases. Moreover, the co-occurrence of spinal ERWTs and a history of spinal anomalies warrants further investigation.

We present the case of a 12-month-old male diagnosed with an extrarenal Wilms tumor found incidentally at the time of inguinal orchiopexy. He was staged and treated according to Children\'s Oncology Group (COG) protocol, with no evidence for disease at the end of treatment. We review the patient\'s presentation and treatment course, followed by a review of current literature on extrarenal Wilms tumor and considerations for management.

Extrarenal Wilms tumor (ERWT) is rare, and its occurrence in the adult recto-vaginal septum is even more uncommon. Importantly, instances of a BRCA2 gene mutation associated with ERWT have not been documented. In this report, we present an unusual case of ERWT situated in the recto-vaginal septum of a 49-year-old woman, accompanied by a concurrent BRCA2 gene mutation. After the tumor\'s second recurrence, the patient experienced symptomatic relief after administering poly (ADP-ribose) polymerase (PARP) inhibitor therapy. Given the limited exposure and understanding of optimal treatment strategies for this distinct tumor, there is a definite need to accumulate further clinical experiences and insight. Consequently, we propose that genetic testing be considered in cases involving tumor recurrence or metastasis, since this may offer valuable information for identifying targets for therapeutic intervention.

Retroperitoneal extrarenal Wilms tumor is a rare condition in children that can be easily misdiagnosed as other retroperitoneal malignancies unrelated to the renal origin. Computerized tomography scan plays a crucial role in diagnosing and distinguishing retroperitoneal malignancies. In this report, we present two cases of retroperitoneal extrarenal Wilms tumor in children who were admitted due to abdominal mass. Laboratory examination did not reveal any significant abnormality. However, a computerized tomography scan revealed a solid or cystic-solid mass in the retroperitoneum accompanied by a bone spur extending from the anterior edge of the vertebral body to the back of the mass, while the origin of the tumor remained unclear. By analyzing these two cases and reviewing previous studies on retroperitoneal extrarenal Wilms tumor in children, we summarized the clinical and imaging characteristics of this rare condition. We also found that the presence of a spinal deformity adjacent to the mass might indicate the possibility of a retroperitoneal extrarenal Wilms tumor.

BACKGROUND: The diagnosis of nephroblastoma outside of the kidneys, in the absence of a renal primary tumor, is known as extrarenal Wilms tumor (ERWT). ERWT is an uncommon entity that typically involves the embryonic path of the developing kidneys and gonads. The occurrence of ERWT in a dysraphic spine is uncommon, with no reported cases of preoperative diagnosis, with all cases diagnosed at pathology. These tumors are malignant and ideally should be completely excised. Thus, preoperative diagnosis would be highly desirable.
METHODS: A newborn female was found to have a lumbar lipoma. Magnetic resonance imaging (MRI) was performed to rule out lipomyelomeningocele. The MRI showed a dorsal lipoma on the terminal spinal cord, as well as a 2 × 2 cm uniformly enhancing mass abutting the bifid posterior elements of L5. The lesion was completely excised, and the pathological diagnosis was ERWT. We report this case with a review of the literature to raise awareness of this association, illustrate the key imaging findings, and document the clinical outcome.
CONCLUSIONS: The lack of pathognomonic radiologic features makes the preoperative diagnosis extremely difficult, but a diagnosis of ERWT should be considered in the context of a soft tissue mass without the typical imaging features of a hemangioma or teratoma.

Extrarenal Wilms tumors are extremely rare with only isolated case reports in the pediatric literature. We present the case of a 2-year old boy who presented with a large abdominal mass and constipation. Pathologic diagnosis of the tumor was extrarenal Wilms tumor (ERWT) with favorable histology. We discuss the diagnostic workup, radiologic and operative findings, treatment and review of the literature.