The authors report the second case of oncocytic melanoma, one of the rarest known melanoma variants. The diagnosis was established by Fontana stain positivity, expression of S100 protein as well as gp100/HMB45, and demonstration of numerous mitochondria by ultrastructure. Because it is known that some oncocytic tumors of the thyroid gland and kidney contain point mutations and common deletions of mitochondrial DNA, the complete mitochondrial DNA of the reported oncocytic melanoma was also studied. It was normal except for 2 private separate point mutations, predicted to be not pathogenic, which do not seem to play any role in the tumor phenotype.
*Baylor Scott & White Health, Temple, TX;
†i3S—Instituto de Investigação e Inovação em Saúde (Institute for Research and Innovation in Health), University of Porto, Porto, Portugal;
‡IPATIMUP—Institute of Molecular Pathology and Immunology of the University of Porto, Porto, Portugal; and
§Department of Pathology, Medical Faculty, University of Porto, Porto, Portugal.
Correspondence: Ludvik R. Donner, MD, PhD, Department of Pathology, Baylor Scott & White Health, Texas A&M College of Medicine, 2401 South 31st Street, Temple, TX 76508 (e-mail: firstname.lastname@example.org).
Supported by Portuguese funds through FCT—Fundação para a Ciência e a Tecnologia—in the framework of project UID/BIM/04293/2013. It was also financed by FEDER—Fundo Europeu de Desenvolvimento Regional funds through the COMPETE 2020—Operational Program for Competitiveness and Internationalization (POCI), Portugal 2020, and by Portuguese funds through FCT—Fundação para a Ciência e Tecnologia/Ministério da Ciência, Tecnologia e Inovação in the framework of the projects “Institute for Research and Innovation in Health Sciences” (POCI-01-0145-FEDER-007274). Further funding was obtained from the project “Advancing cancer research: from basic knowledgment to application” NORTE-01-0145-FEDER-000029: “Projetos Estruturados de I&D&I,” funded by Norte 2020—Programa Operacional Regional do Norte.
The authors declare no conflicts of interest.