A malignant neoplasm involving the spleen. The disease is Monarch Disease Ontology identifier MONDO_0005966 (spleen cancer). Also known as: cancer of spleen, cancer of the spleen, malignant neoplasm of spleen, malignant neoplasm of the spleen, malignant spleen neoplasm, malignant splenic neoplasm, malignant splenic tumor, malignant splenic tumour.