Unusual Metastatic Patterns of Wilms Tumor: A Case Series

Abstract

Wilms tumor (WT) is the most common renal malignancy of childhood. The common metastatic sites are the lungs, liver, and lymph nodes, with brain and bone metastases occurring rarely. Metastatic disease can be present at initial diagnosis or may occur with relapse or disease progression. The majority of relapses in WT occur within the first two years post-treatment. Late relapses are rare. This article describes four cases of WT, each demonstrating an unusual site or timing of metastases. Case 1 presented primarily with jaw metastases, Case 2 presented with bone (vertebrae) and spinal metastases manifesting as paraplegia, at relapse one year after completion of treatment, Case 3 presented with isolated liver metastases four years after treatment completion, and Case 4 presented with brain metastases after six weeks of treatment abandonment. This case series demonstrates the varied pattern of metastases of WT and highlights the need for a high index of suspicion for WT among patients who present with unusual sites of tumor or for metastasis in those who present with neurologic symptoms during or after treatment.

Keywords: child; malignancy; metastases; relapse; unusual sites; wilms tumor.

Figure 1. Contrast-enhanced CT scan of the head (a). Axial bone window (b and c). Axial and coronal reformatted soft tissue window. Large right hemimandibular mass with associated cortical destruction (yellow arrow), showing a large heterogeneously enhancing soft tissue mass, which is mainly exophytic (red arrow) with a smaller intra-oral extension (blue arrow) compressing the tongue.

Figure 2. Axial and sagittal reformatted contrast CT of the abdomen and pelvis revealed a huge well-circumscribed mass (blue arrows) of renal origin evidenced by the claw sign (red arrow) (a and b). It extended to the level of the right hemidiaphragm with displacement of the right lobe of the liver and abdominal vessels.

Figure 3. Photomicrographs showing histopathologic features of stromal predominant WT; (a) ×40 and (b) ×100, a core biopsy of the jaw mass; (c) ×40 and (d) ×100, sections from kidney.

Figure 4. (a, b, and c) Contrast-enhanced CT of the chest and abdomen demonstrated an extensive lobulated and heterogeneously enhancing posterior mediastinal and pleural-based mass (yellow arrows), which displaced the thoracic aorta and heart anteriorly, also infiltrating the erecta spinae muscles, with bony destruction and extensive intraspinal extension ( red arrows). The child also had multiple bilateral lung nodules (blue arrow).

Figure 5. (a and b) Coronal reformatted axial contrast-enhanced abdominopelvic CT scan images. Demonstrating a large well-circumscribed heterogeneously enhancing mass in segments IVa, IVb, V, VI, and portions of VIII of the liver. Exerts mass effect on the right and main portal vein. No tumor thrombus or ascites present. No lung nodules present.

Figure 6. (a) Axial non-contrast head CT scan showing hyperattenuating lesions at the grey, white matter junction (yellow arrows) in the right occipital lobe with surrounding vasogenic edema and a smaller left temporal lobe one (b). The contrast-enhanced axial image showed an anteriorly located right frontal lobe rim-enhancing lesion and a heterogeneously enhancing left parietal lobe lesion with marked vasogenic edema (blue arrows). These were considered metastatic lesions.