Abstract

Liesegang rings (LRs) are peculiar structure of periodic precipitation zones from supersaturated solution in colloidal system. LRs are formed by a process referred to as "the Liesegang phenomenon". Here we describe LRs in renal hemorrhagic cyst from the donor kidney of a 59-year-old man. His general condition was good. Abdominal ultrasonography revealed a simple cyst in the left kidney. After donor nephrectomy for renal transplantation, a 3x2 cm sized cyst containing the brownish necrotic fluid was noted in the upper pole of left kidney. Frozen section from the relatively thickened cystic wall was performed. During frozen section examination, round concentric rings with double-layered outer wall, striations and amorphous central nidus admixed with the foamy macrophages were found and the lesion was originally interpreted as xanthogranulomatous inflammation with unusual crystalline structures in the cytoplasm of macrophages or freely in the interstitium. Macrophages with calcium crystals or malakoplakia were also considered at that time. Additional specimen for the permanent sections showed a simple hemorrhagic renal cyst with areas of small or large aggregates of LRs along the cyst wall. Multiple round ring-like structures ranging from 11 to 42 micrometer in diameter had uniform, pale eosinophilic, radially striated double wall. Histochemical and immunohistochemical stainings for iron, calcium, mucopolysaccharide, amyloid, cytokeratin were negative in these structures. They were highlighted by CD68 immunostaining as well as PAS and Masson's trichrome stainings. Awareness of Liesegang phenomenon in cystic lesions will decrease the possibility of erroneous diagnosis as another type of pathologic process, such as parasitic worms or eggs.

• Keywords: Liesegang rings;Renal cyst;Kidney;