malignant rhabdoid tumour
A rare, highly aggressive round cell tumour that, in contrast to Wilms’ tumour, responds poorly to chemotherapy, metastasises early and has a dismal prognosis (20-25% survival)
Clinical findings Pain–difficult to assess in infants (manifest as fussiness), mass on examination, haematuria, fever, hypertension, metastatic masses in the CNS, increase intracranial pressure.
Differential diagnosis Clear cell sarcoma of kidney, congenital mesoblastic nephroma, rhabdomyosarcoma, Wilms tumour.
Imaging–abdominal CT Large, lobulated mass with hypoattenuating areas of hemorrhage or necrosis within or next to the kidney; the margins may be sharply defined or indistinct. Other findings include linear and curvilinear calcifications, and subcapsular collections of fluid, which is best seen by contrast-enhanced CT.
Lab Anaemia, microscopic haematuria, hypercalcaemia
Molecular pathology Inactivation of SMARCB1—which encodes a component of the ATP-dependent chromatin-remodeling BAF (hSWI/SNF) complex, that plays key roles in cell proliferation and differentiation, and has antiviral and anti-tumour activity—have been linked to malignant rhabdoid tumour.
Prognosis Poor; patients may die within weeks (!) of diagnosis; younger infants have a worse prognosis: 9% survival if diagnosed under age 5 months; 41% if diagnosed age 24 months or older.
Synonyms Rhabdoid tumour of the kidney, rhabdomyosarco-matoid variant of Wilms tumour
References Indian J Pathol Microbiol 2011;54:819-21