Hypercalcemic infantile renal tumors: morphological, clinical, and biological heterogeneity.

Hypercalcemic infantile renal tumors without bone metastases should be considered to be a heterogeneous tumoral entity. Histological and ultrastructural features, different from those of nephroblastoma, should not be exclusively linked with malignant rhabdoid tumors of the kidney. This is reported by the present case, which appears to be a cellular variant of mesoblastic nephroma and was successfully serially transplanted to nude mice. The causes of hypercalcemia in infantile renal tumors are probably related either to NH2-terminal parathormone or to prostaglandin E2 production by the tumoral cells.