Pediatric Papillary Renal Cell Carcinoma in a Horseshoe Kidney: A Case Report with Review of the Literature

Abstract

Renal cell carcinoma is the most common malignancy of the kidney in adults. In children, however, it only accounts for an estimated 1.8 to 6.3% of all pediatric malignant renal tumors. Papillary renal cell carcinoma is the second most common type of renal cell carcinoma in children. We present the case of a 12-year-old boy with a 2-month history of abdominal pain, unexplained weight loss, and gross hematuria. Computed tomography revealed a horseshoe kidney and a well-defined mass of 4 cm arising from the lower pole of the right kidney. Microscopically the tumor was composed of papillae covered with cells with abundant eosinophilic cytoplasm and high-grade nuclei with prominent nucleoli. Immunohistochemistry was performed; EMA, Vimentin, and AMACR were strongly positive while CK7, CD10, RCC antigen, TFE3, HMB-45, and WT-1 were negative. Currently, 10 months after the surgical procedure, the patient remains clinically and radiologically disease-free.

Figure 1

Abdominal computed tomography revealed an ill-defined tumor arising from the lower pole of the right kidney.

Figure 2

Gross photograph of the cut surface of the right kidney showing a heterogeneous tumor mass.

Figure 3

(a) Tumor pseudocapsule composed of fibrous tissue. H&E stain, ×50. (b) Papillae covered by large cells with abundant eosinophilic cytoplasm. H&E stain, ×100. (c) Pseudostratified high-grade nuclei with prominent nucleoli. H&E stain, ×400.

Figure 4

(a) Reactivity to EMA. Immunohistochemical stain with anti-EMA antibody, ×100. (b) Reactivity to Vimentin. Immunohistochemical stain with anti-Vimentin antibody, ×100. (c) Reactivity to AMACR. Immunohistochemical stain with anti-AMACR antibody, ×100.