Sclerotic bodies in nephrogenic systemic fibrosis: a new histopathologic finding.

Nephrogenic systemic fibrosis (NSF--known previously as nephrogenic fibrosing dermopathy) is a systemic disorder observed exclusively in patients with a history of kidney disease associated with renal failure. Reported histopathologic findings of NSF include spindle-shaped fibroblast-like cells with fibrosis, thickened collagen bundles with surrounding spindled and epithelioid cells, increased number of elastic fibers, sparse inflammatory infiltrate and increased stromal mucin. Two populations of multinucleated giant cells (Factor XIIIa and CD68 positive) have also been observed. We observed the presence of sclerotic bodies with entrapped elastic fibers in two cases of NSF, which we interpreted to be collagenous in nature, a finding not previously reported. These bodies should not be confused with osseous metaplasia previously seen in association with NSF, which show lacunae and cells within the osseous bodies that may or may not be calcified. We did not observe lacunae or cells within the sclerotic bodies in our cases. Furthermore, the sclerotic bodies in our cases stained blue on Masson trichrome, whereas previous investigators observed the osseous metaplasia to be red. We suggest that sclerotic bodies may be an additional clue to the diagnosis of NSF.