Pediatric renal tumors represent a diverse group, which include Wilms' tumor (WT), renal cell carcinoma (RCC), clear cell sarcoma of the kidney (CCSK), congenital mesoblastic nephroma, malignant rhabdoid tumor of the kidney (MRTK) and primitive neuroectodermal tumor. WT (85%) and RCC (8%) are the most prevalent types. WT predominates among the 1- to 10-year age group, but RCC exceeds WT in children over age 10 years. Pediatric renal tumors are genetically, histologically and clinically heterogeneous. The overall survival for children with localized WT is currently more than 90%, whereas poorer survival rates are observed for anaplastic WT, metastatic WT, metastatic CCSK, MRTK, metastatic RCC and relapsed WT. Therefore risk-stratified treatment is important to minimize treatment morbidity while preserving survival. This review focuses on distinct characteristics of each tumor type and optimal stratified treatment.
Carcinoma, Renal Cell ; Child ; Humans ; Kidney ; Nephroma, Mesoblastic ; Neuroectodermal Tumors, Primitive ; Rhabdoid Tumor ; Sarcoma, Clear Cell ; Survival Rate ; Wilms Tumor

OBJECTIVETo study the clinicopathologic features, immunophenotype and differential diagnosis of mixed epithelial and stromal tumor of kidney (MEST) and adult cystic nephroma (CN).

METHODSFive cases of MEST and 4 cases of CN were retrospectively analyzed. Immunohistochemical study was carried out and the literature was reviewed.

RESULTSAll of the five patients with MEST were females. Their median age was 45 years. For CN, there were 3 males and 1 female and their median age was 41 years. All patients presented with loin pain and hematuria. On gross examination, MEST was well-circumscribed but non-encapsulated. There was no evidence of haemorrhage or necrosis. Three of the cases were solid in nature. One was composed of a mixture of solid and cystic elements, while the remaining case showed a multicystic cut surface bridged by thick fibrous septa. On the other hand, CN were well-circumscribed and encapsulated. They were multiloculated cystic in nature. The cystic spaces were separated by thin septa and there was no significant solid or necrotic component. Histologically, MEST consisted of proliferation of cystically dilated glands admixed with spindly stromal cells with various cellularity and growth patterns. Both the glandular and stromal elements were well-differentiated with no cytologic atypia identified. The glandular structures in 2 of the cases were partially lined by endometrial or tubal epithelium. In contrast, the thin-walled cystic spaces in CN were lined by a single layer of epithelium.Immunohistochemical study showed that the epithelial cells were positive for pan-cytokeratin and epithelial membrane antigen. The spindle cells in MEST expressed vimentin (5/5), smooth muscle actin (3/5), desmin (4/5), CD10 (5/5), estrogen receptor (4/5) and progesterone receptor (4/5). They were negative for HMB45, CD34, CD117 and S-100 protein. On the other hand, the spindle cells in CN were variably positive for vimentin (4/4), smooth muscle actin (4/4), desmin (1/4), estrogen receptor (3/4) and progesterone receptor (1/4). They were negative for CD10, HMB45, CD34, CD117 and S-100 protein.

CONCLUSIONSBoth MEST and CN are uncommon renal neoplasm. Most of them run a benign clinical course. The stromal cells in MEST show smooth muscle or myofibroblastic differentiation. Areas demonstrating Müllerian features also existed in some cases. MEST and CN share overlapping histological and immunohistochemical features, and may represent spectrum of the same group of lesions.

Actins ; metabolism ; Adult ; Carcinoma, Renal Cell ; pathology ; Desmin ; metabolism ; Diagnosis, Differential ; Epithelial Cells ; metabolism ; pathology ; Female ; Follow-Up Studies ; Humans ; Kidney Neoplasms ; metabolism ; pathology ; Male ; Middle Aged ; Neoplasms, Complex and Mixed ; metabolism ; pathology ; Neoplasms, Cystic, Mucinous, and Serous ; metabolism ; pathology ; Nephroma, Mesoblastic ; pathology ; Receptors, Estrogen ; metabolism ; Retrospective Studies ; Stromal Cells ; metabolism ; pathology ; Vimentin ; metabolism

Chromosome Deletion ; Humans ; Kidney Neoplasms ; WAGR Syndrome/genetics* ; Wilms Tumor

Congenital mesoblastic nephroma is a rare renal tumor that is diagnosed during pregnancy and is associated with polyhydramnios, prematurity, and neonatal hypertension. Differential diagnoses include Wilms tumor, adrenal neuroblastoma, and other abdominal tumors. We report a case of congenital mesoblastic nephroma detected by prenatal ultrasonography as a large fetal renal mass with polyhydramnios at 32 weeks of gestation. Ultrasonography showed a 6x6-cm complex, solid, hyperechoic, round mass in the right kidney. At 35 weeks of gestation, the patient was admitted with preterm premature rupture of membranes and the baby was delivered vaginally. Postnatal ultrasonography and computed tomography showed a heterogeneous solid mass on the right kidney. At the end of the first week of life, a right nephrectomy was performed and subsequent pathological examination confirmed a cellular variant of congenital mesoblastic nephroma with a high mitotic count. Postoperative adjuvant chemotherapy was administered. The newborn was discharged in good condition.
Chemotherapy, Adjuvant ; Diagnosis, Differential ; Drug Therapy ; Humans ; Hypertension ; Infant, Newborn ; Kidney ; Membranes ; Nephrectomy ; Nephroma, Mesoblastic* ; Neuroblastoma ; Polyhydramnios ; Pregnancy ; Prenatal Diagnosis* ; Rupture ; Ultrasonography ; Ultrasonography, Prenatal ; Wilms Tumor

Recently, with the advent of prenatal ultrasonography, renal tumors in the neonatal period are diagnosed with increasing frequency. Detected most solid masses in the neonatal kidney will mostly be proven to be a congenital mesoblastic nephroma but a Wilms' tumor in the neonate is quite uncommon. We found a solid mass in the fetal left kidney at 39th week of gestation by prenatal ultrasonography. The infant, a healthy male in external appearance was delivered by Cesarean section at 40th week of gestation. At one day of age, we confirmed a left renal mass with ultrasonography and this neonate underwent left nephrectomy at nine days of age. The tumor was pathologically diagnosed as stage 1 with favorable histology of Wilms' tumor. Chemotherapy was performed postoperatively according to the EE-regimen of National Wilms' Tumor Studies (NWTS)-4 for 24 weeks. Now the patients is in good condition with no recurrence after postoperative 17 months.
Cesarean Section ; Drug Therapy ; Female ; Humans ; Infant ; Infant, Newborn* ; Kidney ; Male ; Nephrectomy ; Nephroma, Mesoblastic ; Pregnancy ; Prenatal Diagnosis ; Recurrence ; Ultrasonography ; Ultrasonography, Prenatal* ; Wilms Tumor*

The congenital mesoblastic nephroma is the most common renal neoplasm seen in the first few months of life. This tumor usually benign, but local recurrences and metastases have been reported, and treatment is total nephrectomy. This entity must be differentiated from Wilm's tumor so as to avoid unnecessary postoperative irradiation and chemotherapy. Recently, we experienced a case of congenital mesoblastic nephroma in female newborn infant. Diagnosis was made with physical examination, plain roentgenogram of the abdomen, ultrasonography of the abdomen and I.V.P. and confirmed with microscopic examination. A brief review of the related literature was made on this subject.
Abdomen ; Diagnosis ; Drug Therapy ; Female ; Humans ; Infant, Newborn ; Kidney Neoplasms ; Neoplasm Metastasis ; Nephrectomy ; Nephroma, Mesoblastic* ; Physical Examination ; Recurrence ; Ultrasonography ; Wilms Tumor

The congenital mesoblastic nephroma is the most common renal neoplasm seen in the first few months of life. This tumor usually benign, but local recurrences and metastases have been reported, and treatment is total nephrectomy. This entity must be differentiated from Wilm's tumor so as to avoid unnecessary postoperative irradiation and chemotherapy. Recently, we experienced a case of congenital mesoblastic nephroma in female newborn infant. Diagnosis was made with physical examination, plain roentgenogram of the abdomen, ultrasonography of the abdomen and I.V.P. and confirmed with microscopic examination. A brief review of the related literature was made on this subject.
Abdomen ; Diagnosis ; Drug Therapy ; Female ; Humans ; Infant, Newborn ; Kidney Neoplasms ; Neoplasm Metastasis ; Nephrectomy ; Nephroma, Mesoblastic* ; Physical Examination ; Recurrence ; Ultrasonography ; Wilms Tumor

Mixed epithelial and stromal tumor of the kidney(MEST) is a rare, recently described benign renal neoplasm that predominantly affects perimenopausal women. It is composed of dual components of epithelial and stromal cells, and the tumor is characterized by admixed cystic and solid growth patterns. Herein, we report on a case of MEST in a 35-year-old woman who presented with an incidentally found renal tumor. The patient has had no evidence of disease 4 years after the surgery.
Adult ; Epithelial Cells ; Female ; Humans ; Kidney ; Kidney Neoplasms ; Neoplasms, Complex and Mixed ; Stromal Cells

Wilms' tumor, aniridia, genitourinary anomalies, and mental retardation (WAGR) syndrome is caused by deletion of chromosome 11p13, including the Wilms' tumor (WT1) and aniridia gene (PAX6) loci. Here, we report the first case of WAGR syndrome in Korea; the patient was a 2-year-old girl with bilateral aniridia from birth who presented with abdominal distention and mental retardation. Cytogenetically, she had deletion of chromosome 11p11.2-13. Bilateral Wilms' tumors were successfully treated by chemotherapy and surgery. She has been tumor-free for 19 months off chemotherapy with preserved renal function.
Aniridia ; Humans ; Intellectual Disability ; Korea ; Parturition ; Preschool Child ; WAGR Syndrome ; Wilms Tumor

Congenital aniridia is a rare ocular malformation that presents with severe hypoplasia of the iris and various ocular manifestations. Most cases of congenital aniridia are known to be related to mutations in the paired box gene-6 (PAX6), which is an essential gene in eye development. Herein, we report a familial case of autosomal dominant congenital aniridia with four affected members in 3 consecutive generations and describe the detailed ophthalmologic findings for one of these members. As expected, mutational analysis revealed a nonsense mutation (p.Ser122*) in the PAX6 gene. Thus, our findings reiterate the importance of PAX6 mutations in congenital aniridia.
Aniridia* ; Codon, Nonsense ; Family Characteristics ; Genes, Essential ; Humans ; Iris ; WAGR Syndrome ; Wilms Tumor