Case presentation
A 4-year-old male was referred to the pediatric oncology unit after
abdominal computed tomography (CT) performed for his swollen abdomen
demonstrated a 15.7 cm heterogeneous mass on the upper pole of his right
kidney. Furthermore, chest CT showed a right pleural effusion. On
physical examination, there was a palpable, hard, nontender mass
occupying the right hypochondrium and flank, extending down to the right
iliac fossa and crossing the midline. As far as symptoms are concerned,
the patient had unintentionally lost eight kilograms in one month and
experienced intense sudoresis and enuresis.
Complete blood count and renal and hepatic function tests were within
normal limits, while serum AFP was elevated, at 159.87 ng/mL (reference
value <10 ng/mL). To evaluate his pleural effusion, the
patient underwent ultrasound (US) examination of the thorax, which found
evidence of chest cavity invasion by an abdominal mass measuring 14.9 x
12.2 x 9.9 cm (935.8 cm3). Due to the highly elevated
tumor dimensions, it was not possible to determine its origin, whether
renal or hepatic, requiring a biopsy for accurate identification of the
primary tumor site. Anatomopathological analysis of the biopsied mass
revealed a morphological picture that could correspond to a mixed HB or
a triphasic WT — the former being composed of both an epithelial
(fetal and embryonal) and a mesenchymal component and the latter of
blastema, stroma and epithelial cells — so that an immunohistochemical
analysis was strictly necessary for accurate diagnostic definition
[13, 14]. Immunohistochemical analysis of the tru-cut biopsied mass
was negative for hepatic markers, but expressed specific markers
(cytokeratin AE1/AE3, CD57, integrase interactor 1 and Wilms tumor 1)
compatible with triphasic nephroblastoma. The patient was thus diagnosed
with stage IV WT.