Leiomyoma of the ureter

A 57-year-old woman was referred following an acute episode of left-sided pyelonephritis associated with Klebsiella spp infection. After antibiotic treatment and resolution of the infection, the left flank pain continued and imaging revealed left hydronephrosis and hydroureter, with apparent obstruction on the left pelvic sidewall associated with the presence of a round lesion approximately 36 mm in diameter (Fig. 1). The left ovary appeared to be in close relation to the obstructing lesion, but separate. The right renal tract was normal. Her serum creatinine level was elevated at 102 μmol/L, but tumour markers were equivocal with normal results for carcinoembryonic antigen and CA-125, but an elevated level of CA19.9 (84 kU/L)

Paracellin-1, a renal tight junction protein required for paracellular Mg2+ resorption

Epithelia permit selective and regulated flux from apical to basolateral surfaces by transcellular passage through cells or paracellular flux between cells. Tight junctions constitute the barrier to paracellular conductance; however, Little is known about the specific molecules that mediate paracellular permeabilities. Renal magnesium ion (Mg2+) resorption occurs predominantly through a paracellular conductance in the thick ascending limb of Henle (TAL), Here, positional cloning has identified a human gene, paracellin-1 (PCLN-1), mutations in which cause renal Mg2+ wasting. PCLN-1 is Located in tight junctions of the TAL and is related to the claudin family of tight junction proteins. These findings provide insight into Mg2+ homeostasis, demonstrate the role of a tight junction protein in human disease, and identify an essential component of a selective paracellular conductance