Wilms tumour wilms·tu·mour uncommon noun 1. malignant renal tumor of young children characterized by hypertension and blood in the urine and the presence of a palpable mass SynonymsWilms' tumorWilms tumouradenomyosarcomanephroblastomaembryoma of the kidney Related words Broader terms sarcoma WordNet 2.1 (Princeton University). WordNet 2.1 Copyright Princeton University. All rights reserved.