Oncocytic metaplasia occurring in melanoma.
BACKGROUND
Oncocytosis is a cellular feature characterized by the presence of a finely granular eosinophilic cytoplasm due to the accumulation of mitochondria. While this histologic trait can be found in normal tissues, it is also seen pathologically as a degenerative phenomenon. We recently reviewed a spectrum of oncocytic melanocytic nevi that did not have clinical significance. We now describe similar changes in melanoma.


METHODS
We retrospectively reviewed 12 melanomas noted to have prominent granular eosinophilic cytoplasm and completed ultrastructural studies. We obtained patient histories and clinical follow-up information from the patients' physicians.


RESULTS
All cases were primary melanomas and showed prominent oncocytosis in the majority of the lesional melanoma cells. Oncocytosis was observed in both melanoma in situ and invasive melanoma with a wide range of Breslow thicknesses (range, 0.45-5.05 mm). It occurred in the presence and absence of ulceration, regression, vascular invasion, and brisk tumor infiltrating lymphocytes. Ultrastructural studies revealed melanocytes with numerous distorted mitochondria.


CONCLUSIONS
Melanoma is capable of presenting in a variety of histologic guises, including oncocytic change. While our observations are preliminary, this pathologic curiosity likely represents a degenerative phenomenon of little prognostic importance.
Jih
Debra M
DM
Department of Dermatology, MetroHealth Medical Center, Case Western Reserve University, 2500 MetroHealth Dr, Cleveland, OH 44109-1998, USA.
Morgan
Michael B
MB
Bass
Jonathan
J
Tuthill
Ralph
R
Somach
Stephen C
SC
D000368:Aged; D000369:Aged, 80 and over; D005260:Female; D006801:Humans; D008297:Male; D008545:Melanoma / Q000473:pathology*; D008679:Metaplasia; D008875:Middle Aged; D024862:Oxyphil Cells / Q000473:pathology*; D012189:Retrospective Studies; D012867:Skin / Q000473:pathology*; D012878:Skin Neoplasms / Q000473:pathology*