MedGen

A solid, unencapsulated tumor of the kidney composed of spindle mesenchymal cells that resemble fibroblasts or muscle cells. The homogeneous mass typically extends into the renal parenchyma and replaces most of the kidney. In most cases, mesoblastic nephroma is benign and occurs in the fetus or newborn, and rarely in the older child or the adult. [from MONDO]

Congenital mesoblastic nephroma is a type of kidney tumor that is usually found before birth by ultrasound or within the first 3 months of life. It contains fibroblastic cells (connective tissue cells), and may spread to the other kidney or to nearby tissue. [from HPO]

A chromosomal abnormality consisting of the presence of one chromosome in addition to the normal diploid number. [from NCI]

A fibroblastic sarcoma is a malignant tumor derived from fibrous connective tissue and characterized by immature proliferating fibroblasts or undifferentiated anaplastic spindle cells. [from HPO]

A fibrosarcoma that occurs in infants. It shares identical morphologic features with adult fibrosarcoma but carries the t(12;15)(p13;q25) translocation that results in ETV6-NTRK3 gene fusion. It usually affects the superficial and deep soft tissues of the extremities. The prognosis is generally much more favorable than for adult fibrosarcoma, and it rarely metastasizes. [from NCI]

Any neoplasm composed of fibrous tissue. [from HPO]

A tumor (abnormal growth of tissue) that arises from the soft tissue. The most common types are lipomatous (fatty), vascular, smooth muscle, fibrous, and fibrohistiocytic neoplasms. [from HPO]

A congenital mesoblastic nephroma characterized by increased cellularity, sheet-like proliferation of fibroblastic cells, and increased mitotic activity. Necrotic changes are commonly present. [from NCI]

A congenital mesoblastic nephroma characterized by the presence of interlacing fascicles of fibroblastic cells, low mitotic activity, and collagen formation. [from NCI]

A malignant mesenchymal neoplasm composed of fibroblasts, and characterized by collagen production and usually a herringbone architectural pattern. [from NCI]

A usually aggressive malignant neoplasm arising from the kidney. It is characterized by the presence of spindle-shaped fibroblasts and collagenous stroma formation in a herringbone growth pattern. [from NCI]