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

Mesoblastic nephroma is an important differential diagnosis of a renal mass occurring in the neonatal period or in early childhood. It is a rare monomorphous congenital renal neoplasm most commonly recognized during the first 3 months of life. With the widespread application of ultrasound imaging, many cases are recognized prior to birth. We report a case of mesoblastic nephroma detected by ultrasonograph at 36 weeks of intrauterine fetal life and removed after birth. It showed a well circumscribed, grayish white, solid mass measuring 4x3x2 cm. The tumor was predominantly a classic type with a focal cellular pattern. Immunohistochemical and electron microscopic studies were done.
Diagnosis, Differential ; Kidney ; Kidney Neoplasms ; Nephroma, Mesoblastic* ; Parturition ; Ultrasonography

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

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

Diagnosis, Differential ; Humans ; Kidney ; pathology ; Kidney Neoplasms ; diagnosis ; pathology ; Nephroma, Mesoblastic ; diagnosis ; pathology

The descriptive term "mixed epithelial and stromal tumor of the kidney" was recently proposed for a group of renal tumors characterized histologically by a mixture of stromal and epithelial proliferation. It is a rare benign neoplasm of the kidney which has been reported under various names such as adult type mesoblastic nephroma or others. We report a case of mixed epithelial and stromal tumor in a 47 yr old female patient presenting as a partly cystic and partly solid renal mass. Microscopically, the tumor exhibited spindle cell component in solid portion and epithelial proliferation around microcystic areas. Immunoreactive profiles and ultrastructural examination suggested myofibroblastic nature of the stromal cells. We believe this case exemplifies a unique adult renal tumor displaying both epithelial and stromal neoplastic component and has a few unusual features worthy of attention.
Nephroma, Mesoblastic/pathology ; Neoplasms, Glandular and Epithelial/*pathology ; Middle Aged ; Kidney Neoplasms/*pathology ; Humans ; Female ; Diagnosis, Differential

Mesoblastic nephroma is an uncommon renal tumor reported in infants but rarely in adults. We describe a case of calcified mesoblastic nephroma occurring in an adult. It is difficult, on the basis of radiologic images, to differentiate between calcified mesoblastic nephroma and calcified renal cell carcinoma.
Adult* ; Carcinoma, Renal Cell ; Humans ; Infant ; Nephroma, Mesoblastic*

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

Congenital mesoblastic nephroma (CMN) is the most common renal tumor in the first year of life. Here, we present unique findings of cellular variant CMN seen on prenatal and postnatal MRI with diffusion-weighted imaging (DWI).The mass was well-visualized on prenatal MR DWI with diffusion restriction in the solid portions. After excision of the mass, follow-up whole body MRI with DWI helped identify local tumor recurrence with suspicious liver metastasis. This hepatic lesion also showed diffusion restriction.
Adult ; Combined Modality Therapy ; Diffusion Magnetic Resonance Imaging/*methods ; Female ; Humans ; Infant, Newborn ; Kidney Neoplasms/*congenital/therapy ; Liver Neoplasms/*secondary/therapy ; Nephroma, Mesoblastic/*congenital/therapy ; Pregnancy