Primary epithelioid angiosarcoma of the adrenal gland

Primary angiosarcomas of the adrenal gland are exceptionally rare vascular tumors. We report a case of a 63-year-old man with an epithelioid angiosarcoma of the left adrenal gland. Visualized on computed tomography as a nonhomogeneous round mass, the tumor measured 3 cm in diameter. Histology showed a vascular tumor composed of epithelioid cells with vesicular nuclei and prominent nucleoli that lined irregular vascular spaces and also formed solid areas and showed pleomorphism and rare mitotic activity. Immunohistochemical stain confirmed the diagnosis of epithelioid angiosarcoma. We report our findings and review previously described literature cases of this rare entity.

Pigmented renal clear cell carcinoma with melanocytic differentiation

Renal cell carcinoma (RCC) is the most common malignant tumor of the adult kidney, and its incidence has been steadily rising. RCC consists of several subtypes, each of which has its own clinical features, and cytogenetic and molecular characteristics. Recognizing histologic patterns of RCC is important not only for correct diagnosis, but also for providing insight into the biological behavior of the tumor and subsequent appropriate medical care for the patient. Pigments other than hemosiderin has been observed in RCC, but none of them have been proved to be melanin. Melanotic tumors, either primary or metastatic, are rare in the kidney. We present an unusual case of melanin-pigmented clear cell RCC with melanocytic differentiation, an unusual variant that may lead to errors in diagnosis and treatment.

Ureteric bud cells secrete multiple factors, including bFGF, which rescue renal progenitors from apoptosis

Kidney development requires reciprocal interactions between the ureteric bud and the metanephrogenic mesenchyme. Whereas survival of mesenchyme and development of nephrons from mesenchymal cells depends on signals from the invading ureteric bud, growth of the ureteric bud depends on signals from the mesenchyme. This codependency makes it difficult to identify molecules expressed by the ureteric bud that regulate mesenchymal growth. To determine how the ureteric bud signals the mesenchyme, we previously isolated ureteric bud cell lines (UB cells). These cells secrete soluble factors which rescue the mesenchyme from apoptosis. We now report that four heparin binding factors mediate this growth activity. One of these is basic fibroblast growth factor (bFGF), which is synthesized by the ureteric bud when penetrating the mesenchyme. bFGF rescues three types of progenitors found in the mesenchyme: precursors of tubular epithelia, precursors of capillaries, and cells that regulate growth of the ureteric bud. These data suggest that the ureteric bud regulates the number of epithelia and vascular precursors that generate nephrons by secreting bFGF and other soluble factors.

Variation in charge on red cells of patients with different glomerulopathies

The negative charge on the surface of red blood cells may reflect the charge on the glomerular capillaries. Measurements were made of the charge on the red cells of patients with minimal change nephropathy (MCN), membranous nephropathy (IMN), and IgA nephropathy (IgAN) during complete or partial remission. The charge was significantly less in patients with MCN and IMN than in patients with IgAN. Since blood was taken during clinical remission, the differences probably represent the pre-morbid state. Low charge was associated with MCN and IMN, which usually present with heavy proteinuria, and high charge with IgA nephropathy, in which heavy proteinuria is rare. Patients with low red-cell charge are, therefore, susceptible to the development of heavy proteinuria and patients with high charge are protected. The site of deposition or formation of immune complexes may also be determined indirectly by charge.