Diagnosis of<unk>  and its particular type (i.e. classic, mixed, or cellular) is made by histological examination of tissues obtained at surgery. Besides its histological appearance, various features of this disease aid in making a differential diagnosis that distinguish it from the following childhood neoplasms: * Wilms tumor is the most common childhood kidney neoplasm, representing some 85% of cases. Unlike<unk> , 3 years of age. Bilateral kidney tumors, concurrent birth defects, and/or metastatic disease at presentation favor a diagnosis of Wilms tumor. * congenital infantile sarcoma is a rare aggressive sarcoma typically presenting in the lower extremities, head, or neck of infants during their first year of life. The histology, association with the ETV6-NRTK3 fusion gene along with certain chromosome trisomies, and the distribution of markers for cell type (i.e. cyclin D1 and Beta-catenin) within this tumor are the same as those found in cellular<unk> .<unk>  and congenital infantile sarcoma appear to be the same diseases with<unk>  lymphoma originating in the kidney and congenital infantile sarcoma originating in non-renal tissues. * Rhabdoid tumor, which accounts for 5-10% of childhood kidney neoplasms, occurs predominantly in children from 1 to 2 years of age. Unlike<unk> , rhabdoid tumors may present with tumors in other tissues including in ~13% of cases, the brain. Rhabdoid tumors have a distinctive histology and abnormalities (i.e. loss of heterozygosity, single nucleotide polymorphism, and deletions) in chromosome 22. * Clear cell sarcoma of the kidney, which is responsible for 5-10% of childhood pediatric tumors, occurs predominantly in children from 2 to 3 years of age. Unlike<unk> , clear cell sarcoma of the kidney presents with metastasis, particularly to bone, in 5-6% of cases; it histology is diverse and has been mistaken for<unk> . One chromosomal translocations t,(10;17)(q22;p13), has been repeatedly reported to be associated with clear cell sarcoma of the kidney. * Infantile myofibromatosis is a fibrous tumor of infancy and childhood most commonly presenting during the first 2 years of life as a single subcutaneous nodule of the head and neck region or less commonly as multiple lesions of skin, muscle, bone, and in ~33% of these latter cases, visceral organs. All of these lesions have an excellent prognosis and can regress spontaneously except for those in which there is visceral involvement where the prognosis is poor. While infantile myofibromatosis and classic<unk>  have been suggested to be the same diseases because of their very similar histology, studies on the distribution of cell-type markers (i.e. cyclin D1 and Beta-catenin) indicate that they have different cellular origins.
Mesoblastic nephroma
Cystic nephroma
Renal medullary fibroma
Medullary sponge kidney
Renal anaplastic sarcoma
Papillary renal cell carcinoma
Renal medullary carcinoma
Renal oncocytoma