Malignant rhabdoid tumor of the kidney(MRTK), an uncommon renal tumor found in children, is one of the most lethal neoplasms of early life. It was first recognized during a review of the first National Wilms' Tumor Study(NWTS) as an extremely aggressive neoplasm whose appearance often mimicks those of skeletal muscle tumors, but without histological, immunohistochemical, and ultrastructural markers of rhabdomyogenesis. Herein we present two cases of malignant rhabdoid tumor of the kidney, one occurring in a 6-month-old male baby, and the other in a 123-month-old girl. They presented a huge tender mass on the left upper quadrant of the abdomen. Microscopically, each case was very cellular and composed of sheets of round or polygonal cells with ample cytoplasm often containing eosinophilic filamentous inclusions and round vesicular nuclei with prominent nucleoli. Case 1 showed lymphomatoid pattern, but case 2 showed foci of several variant patterns associated with classic appearances. The tumor cells showed a strong reactivity for vimentin in both cases. Unusually, case 2 showed focal reactivity for epithelial membrane antigen(EMA), muscle specific actin, and smooth muscle actin. Ultrastructural study confirmed the presence of whorled bundles of intermediate filaments in paranuclear position, and a prominent nucleolus.
Child ; Male ; Female ; Humans

The preeclamptic nephropathy is characterized by swelling of endothelial cells, interposition of mesangial cells and matrix, subendothelial deposits of incompletely defined material, and thickening of the capillary walls. To determine the distribution of extracellular matrix (ECM) components in preeclamptic nephropathy, the immunohistochemical study was performed in ten renal biopsy cases using antisera to human type I, III, IV, and VI collagens, fibronectin, and laminin. In preeclamptic nephropathy, the accumulation of type IV and VI collagens, fibronectin was observed in moderate amount in the mesangium and, to some extent, in the thickened capillary walls, particularly in the subendothelial layer. In segmentally sclerotic lesions seen in six cases, the amount of type IV collagen was partly decreased, whereas those of type VI collagen and fibronectin were slightly increased. Type I collagen was expressed to a mild degree in the expanded mesangium and segmentally sclerotic lesions. The results suggest that the expression of ECM in the mesangium is increased in preeclamptic nephropathy, and the deposition of ECM components may be involved in the development and the reparative process of the characteristic glomerular lesions. The formation of sclerotic lesions may be linked to the alternative accumulation of ECM components.
Biopsy ; Capillaries ; Collagen ; Collagen Type I ; Collagen Type IV ; Collagen Type VI ; Endothelial Cells ; Extracellular Matrix* ; Fibronectins ; Humans ; Immune Sera ; Laminin ; Mesangial Cells

Normal human glomerular basement membrane (GBM) and mesangial matrix (MM) contain several different basement membrane components in varying degrees. The characteristic morphological and ultrastructural changes in patients with diabetic nephropathy are the thickening of the GBM and the expansion of the MM. In order to investigate the changes of extracellular matrix components in diabetes, the immunohistochemical localization was performed in 17 cases with different degrees using antisera to human collagen types I, III, IV, VI, fibronectin, and laminin. The following results were obtained: 1. The reactivity for collagen IV was increased in expanded MM in the diffuse glomerulosclerosis (GS). With the progression to the nodule formation, collagen IV was prominently decreased in the peripheral area of the nodules. 2. Collagen VI was increased in GBM and MM in the diffuse GS, it was especially prominent in the expanded MM. With the progression to nodule formation, collagen VI was prominently increased in the periphery of the nodules. 3. Interstitial collagen I and III were not stained in many of the cases with the diffuse GS. With the progression to nodule formation, these were slightly expressed. A lamellar pattern of positive reaction was noted at the periphery of the late nodular lesions. 4. Fibronectin was increased in GBM & MM in the diffuse GS, it was especially intense in the MM. With the progression to the nodule formation, the reactivity of antibody to the fibronectin was decreased. 5. Laminin was weakly stained along the GBM & trace in the MM, but was not changed in the nodular GS. In summary, the expanded mesangial matrix in the diffuse GS showed a markedly increased staining for collagen IV, fibronectin and collagen VI. Less intense linear staining for collagen VI, fibronectin, laminin, collagen IV and collagen III was noted along the GBM. In the nodular GS, the composition of the early nodules resembled that of the diffuse GS. However, the late nodular lesion of the nodular GS revealed decreased reactivity for collagen IV and fibronectin at the periphery of the nodule, where collagen VI and interstitial collagen I and III were increased in laminated pattern.
Basement Membrane ; Collagen ; Diabetic Nephropathies* ; Extracellular Matrix* ; Fibronectins ; Glomerular Basement Membrane ; Humans ; Immune Sera ; Laminin

Fibroepithelial polyps of the ureter are usually acquired rather than congenital. Most polyps are hamartomatous growths which tend to arise in the proximal portion of the left ureter. Most patients exibit either hematuria or persistent flank pain secondary to partial ureteral obstruction. Because of false positivity of urine cytology, as well as intravenous pyelogram, the correct diagnosis is confused with malignancy. Herein we report four cases of ureteral fibroepithelial polyp, which are associated with stones resulting in partial obstruction of the ureter. One of the four cases is associated with nephrogenic adenoma in the lamina propria of the adjacent ureter. The following report describes clinicopathologic findings of fibroepithelial polyp with review of literatures.
Adenoma

Proliferative activity of a malignant tumor is known to reflect its biological aggressiveness. Proliferating cell nuclear antigen (PCNA) is a marker of cellular proliferation, and silver-stained nucleolar organizer regions (AgNORs) have been shown to correlate with ploidy and proliferative activity of cells. In transitional cell carcinoma of the renal pelvis, the prognostic value of these markers has not been well defined. We studied PCNA expression and the AgNORs count in 22 transitional cell carcinoma of the renal pelvis to assess their prognostic significance compared with their cumulative survival rate, the stage of disease and histopathologic features of the tumors. An immunohistochemical method and a standard colloidal silver staining were used. The mean percentage of PCNA positivity (PCNA index) and the mean number of AgNORs per nucleus (AgNORs score) were determined. In a multivariable analysis, PCNA indexes were significantly associated with tumor stage (p=0.024), whereas AgNORs scores were not significantly associated with the stage or histopatholgic features of the tumors. Histologic grade was correlated to disease stage at a significant level (p=0.000). But there was a trend of low tumor PCNA-indices or AgNORs counts with survival advantage for patients, but this did not reach statistical significance. The results suggest that the fraction of PCNA positive nuclei would be useful for investigating the malignant potential of renal pelvic cancers, although their clinical use as markers of biologic behavior may be limited.
Carcinoma, Transitional Cell* ; Cell Proliferation ; Colloids ; Humans ; Kidney ; Kidney Pelvis* ; Nucleolus Organizer Region ; Pelvic Neoplasms ; Ploidies ; Proliferating Cell Nuclear Antigen* ; Silver Staining ; Survival Rate

Fibrous pseudotumor of the testicular tunics is a rare benign fibrous proliferative disorder, but it is the second most common mass-forining lesion of the testicular tunics. While these lesions are not strict neoplasms, they do form nodules and are often mistaken for neoplasms. Herein, we report 2 cases of fibrous pseudotumor with characteristic histologic findings. Both cases had been incidentally found as slow growing scrotal masses and underwent excision. There were several nodules along the testicular tunics which had bulging whitish-gray cut surface with focal myxoid change and a whorling appearance. These two cases showed the histologic spectrum seen in fibrous pseudotumor from a haphazard arrangement of fibroblastic type cells with intervening collagen and focal lymphocytic infiltrates in case 1, to a densely collagenized lesion in case 2.

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

Inflammatory pseudotumor of the urinary bladder is an unusual, benign mesenchymal proliferative lesion of the submucosal stroma easily mistaken for a malignant neoplasm clinically and histologically. We present a case and describe the clinical presentation and radiologic, histologic, histochemical, immunohistochemical, and ultrastructural findings. A 23-year old patient presented with sudden onset of gross painless hematuria for 3 months. There was no previous instrumentation or surgery involving the genitourinary tract. Cystoscopy revealed a large polypoid and ulcerated bladder mass. The lesion consisted of plump spindle shaped, fibroblast-like cells embedded in a myxoid stroma. Mitotic figures were negligible and the lesion showed encroachment on the superficial muscle bundles. The spindle cells were immunoreactive for vimentin and muscle specific actin. Immunohistochemical and ultrastructural findings revealed the fibroblastic-myofibroblastic nature of this lesion. Complete surgical excision by partial cystectomy was successful in eradicating the lesion. The findings are described with a discussion of the pathogenesis and review of the literature.

Lobular carcinoma of the male breast is very rare, because of the absence of lobules in the normal male breast. Herein, a case of lobular carcinoma of the male breast with cellular features of signet ring cells is described. A 57-year-old man presented with a left breast mass. Histologic examination showed classic invasive lobular carcinoma with in situ component. Most infiltrating tumor cells had a prominent signet ring cell appearance. The patient was phenotypically male and had fathered children. There was no history of predisposing factors to breast lesion, such as hormone use or gynecomastia.
Breast* ; Carcinoma, Lobular* ; Causality ; Child ; Fathers ; Gynecomastia ; Humans ; Male* ; Middle Aged

An ossifying fibromyxoid tumor of soft parts is a rare, recently described, fibro-osseous neoplasm of uncertain histogenesis. It occurs most frequently within the subcutis or skeletal muscle of the extremities. Its biologic behavior is generally regarded as benign with at worst a locally aggressive clinical course. But, atypical and malignant variants have been recently reported. Herein we report a case of a benign ossifying fibromyxoid tumor which occurred in the left upper back of 41-year-old man. The tumor is composed of uniformly round or polygonal cells arranged in cords or nests which are separated by myxoid and hyalinzed fibrous matrix and associated with irregular bony trabeculae. The tumor cells are strong positive for vimentin. Ultrastructural findings and a review of literatures are added.
Adult ; Extremities ; Humans ; Muscle, Skeletal ; Vimentin