Renal oncocytoma with prominent intracytoplasmic vacuoles of mitochondrial origin.
OBJECTIVE
We observed two oncocytomas with prominent intracytoplasmatic vacuoles. To investigate if this previously undescribed finding is a diagnostic feature and compatible with the diagnosis of oncocytoma, we characterized these vacuoles by electron microscopy and immunohistochemistry.


RESULTS
The tumours were analysed by transmission electron microscopy. Immunohistochemistry was performed with antimitochondrial antibody, anti-Golgi-zone antibody, anti-lysozyme antibody and anti-human-trans-Golgi-network antibody. By electron microscopy, the vacuoles were found to be double-membrane-bounded, and some contained fragmented christae. Immunohistochemistry showed a positive reaction of the vacuoles with anti-mitochondrial antibody. Staining with anti-Golgi-zone antibody, anti-lysozyme antibody and anti-human-trans-Golgi-network antibody was negative.


CONCLUSIONS
Both tumours are benign oncocytomas. The phenomena of cells with prominent intracytoplasmatic vacuoles is not inconsistent with the diagnosis of oncocytoma. The vacuoles are of mitochondrial origin and may develop, by balloon degeneration, as a mechanism of mitochondrial involution and elimination.
Koller
A
A
Department of Clinical Pathology, Universität Wien, AKH Wien, Austria.
Kain
R
R
Haitel
A
A
Mazal
P R
PR
Asboth
F
F
Susani
M
M
D018249:Adenoma, Oxyphilic / Q000378:metabolism / Q000473:pathology*; D000328:Adult; D000911:Antibodies, Monoclonal / Q000032:analysis; D006801:Humans; D007150:Immunohistochemistry; D007680:Kidney Neoplasms / Q000378:metabolism / Q000473:pathology*; D008297:Male; D008854:Microscopy, Electron; D008875:Middle Aged; D008928:Mitochondria / Q000276:immunology / Q000473:pathology* / Q000648:ultrastructure; D014617:Vacuoles / Q000737:chemistry / Q000473:pathology* / Q000648:ultrastructure
D000911:Antibodies, Monoclonal