Contributed by Mariana Cajaiba, MD
Contributed by Mariana Cajaiba, MD
CLINICAL HISTORY AND PATHOLOGIC FINDINGS
This patient is a 7-month old baby boy who underwent kidney transplantation due to congenital steroid-resistant nephrotic syndrome with progressive renal failure. Additional clinical history included bilateral inguinal exploration followed by right orchidopexy due to cryptorchidism; the left testis had not been found on surgical exploration. Physical examination disclosed a well-developed baby boy with normal male genitalia and a non-palpable left testis.
The renal transplantation procedure was accompanied by bilateral nephrectomy. During the surgery, the left testis was identified in the retroperitoneum and resected. Gross examination disclosed a 1.0 cm testis with a greyish-white well-circumscribed nodule underneath the tunica albuginea, whereas the right kidney was remarkable for a 1.8 cm ovoid mass located on the upper pole, apparently confined to the parenchyma. The remaining testicular and right kidney parenchyma appeared grossly normal, as well as the left kidney.
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Microscopic examination of the left testis revealed a neoplasm composed of cystic follicular structures lined by cuboidal epithelium, intermixed with solid areas and foci of immature-appearing stroma (Figures 1, 2, 3, and 4). The cystic structures were filled by eosinophilic proteinaceous material with occasional calcifications; in some areas, these structures appeared to be continuous with the non-neoplastic seminiferous cords. The adjacent testicular parenchyma showed focal cords with abnormal shapes, and a thin, poorly collagenized tunica albuginea (Figure 5).
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Histological examination of both kidneys showed several abnormal glomeruli characterized by expansion and sclerosis of mesangial matrix accompanied by podocyte hypertrophy (Figures 6 and 7). Renal tubules showed variable degrees of atrophy and dilation, sometimes with a microcystic aspect (Figure 8). The interstitium was mildly fibrotic. Both kidneys displayed several well-defined areas of immature parenchyma delineating the periphery of renal lobules, characterizing nephroblastematosis (Figure 9). The right kidney tumor consisted predominantly of sheets of immature-appearing small round blue cells in a haphazard pattern, sometimes intermixed with tubular structures (Figure 10).
