What is your diagnosis? Spinal nephroblastoma

Spinal cord nephroblastoma in dogs: 11 cases (1985-2007)

OBJECTIVE

To evaluate clinical features and outcome of dogs with a confirmed spinal cord nephroblastoma and to describe the use of Wilms tumor-1 (WT-1) immunohistochemical staining to confirm a diagnosis of nephroblastoma in dogs.

DESIGN

Retrospective case series. Animals-11 dogs with a spinal cord nephroblastoma.

PROCEDURES

Medical records of dogs with a spinal cord nephroblastoma were reviewed. Information extracted included signalment, history, clinical signs, results of diagnostic testing, tumor location, treatment, and outcome. The diagnosis was confirmed through histologic review and WT-1 immunohistochemical staining of a tumor sample. In dogs with negative results for staining with WT-1, staining for cytokeratin, vimentin, and glial fibrillar acidic protein was performed.

RESULTS

11 dogs had a spinal cord tumor with a histologic appearance and immunohistochemical staining consistent with a nephroblastoma. Positive results for staining with WT-1 were detected in 9 of 11 dogs. Age at admission ranged from 5 to 48 months (median, 14 months). Nine dogs were female. All had progressive paraparesis, paraplegia, or ataxia. Duration of clinical signs ranged from 2 to 60 days (median, 14 days). Median survival time was 30 days from the time of diagnosis. Median survival time in dogs treated via surgical resection was 70.5 days.

CONCLUSIONS AND CLINICAL RELEVANCE

The prognosis for dogs with a spinal cord nephroblastoma appeared to be poor, although combined surgical resection and radiation therapy may provide a good functional outcome. Results for staining with WT-1 can be used to support a diagnosis of nephroblastoma.

IMAGING OF A SPINAL NEPHROBLASTOMA IN A DOG

An 8-month-old German Shepherd dog was presented for investigation of pelvic limb gait abnormality. Neurolocalization indicated a T3-L3 spinal cord lesion. The myelographic appearance was of an intramedullary lesion at T9/10, but upon subsequent magnetic resonance imaging it was determined that the mass was extramedullary. A diagnosis of nephroblastoma was made on histological examination. The imaging features of this rare tumor and the differentiation of intradural-extramedullary and intramedullary masses are discussed.