Urinary System
Kidney - Metaplasia, Osseous
Narrative
Comment:
Osseous metaplasia is characterized by mature-appearing bone in the renal parenchyma. It is usually noted as a focal lesion in the cortex and is regarded as a spontaneous lesion of no pathologic significance. Osseous metaplasia may vary in size, and hematopoietic cells may be present in larger lesions (Figure 1 and Figure 2). Osseous metaplasia needs to be distinguished from mineralization.
Recommendations:
Osseous metaplasia should be recorded but need not be graded.
References:
Montgomery CA, Seely JC. 1990. Kidney. In: Pathology of the Fischer Rat: Reference and Atlas (Boorman GA, Eustis SL, Elwell MR, Montgomery CA, MacKenzie WF, eds). Academic Press, San Diego, 127-153.
Abstract: http://www.ncbi.nlm.nih.gov/nlmcatalog/9002563