Abstract
An adult male, 268 cm (straight line length), 279.7 kg pygmy sperm whale (Kogia breviceps) stranded live along the Atlantic coast of Ocean City, Maryland and was humanely euthanized. On gross examination, 20 raised, white, irregularly round, sessile, verrucous masses, 0.5 to 1.5 cm in diameter, were present on the ventral surface of the penis. Histologically, the raised masses were composed of hyperplastic epidermis with prominent rete pegs and intranuclear, eosinophilic inclusion bodies within the stratum spinosum and stratum corneum. The supporting fibrovascular stroma was continuous with the underlying dermis. The stratum basale was hyperplastic with up to 3 mitotic figures per HPF (400x) and contained occasional cells with a clear, round intracytoplasmic vacuole which peripheralized the nucleus, which extended into the adjacent stratum spinosum. Intranuclear inclusion bodies were observed at the junction of the stratum spinosum and the parakeratotic stratum corneum. A similar lesion was present within the esophagus. Immunohistochemical staining using an antibody produced against bovine papillomavirus 1 which widely cross reacts with numerous species was negative. Papillomas are generally benign neoplasms that affect epidermal and mucosal surfaces and can range from small squamous plaques to large nodular warts.3 In cetaceans, cutaneous, oral, gastric and genital papillomas have been reported in a common dolphin, narwhal, harbor porpoises, killer whales, beluga whales, a blue whale, Atlantic white-sided dolphins, bottlenose dolphins, a beaked whale, a sperm whale, dusky dolphins, long snouted common dolphins, and Burmeister's porpoises.1-10 Viral etiologies in cetaceans include papillomavirus and herpesvirus, while pollution, parasites, fungi, chemicals, and genetics, as demonstrated in other species, are proposed etiologies.2 Additional diagnostics are needed to determine the cause of the lesion in this case and to establish similarity to previously reported cases.
Acknowledgements
The authors thank Jennifer Dittmar and Dr. Jimmy Tragle of the National Aquarium, Baltimore, Marine Animal Rescue Program, staff from the Smithsonian Institution and National Zoo who assisted in sample collection, and histology lab personnel at the University of Georgia, College of Veterinary Medicine.
References
1. Bossart GD, Cray C, Solorzano JL, Decker SJ, Cornell LH, Altman NH. Cutaneous papilloma viral-like papillomatosis in a killer whale (Orcinus orca). Marine Mamm Sci. 1996;12(2):274–281.
2. De Guise S, Lagacé A, Béland P. Gastric papillomas in eight St. Lawrence beluga whales (Delphinapterus leucas). J Vet Diagn Invest. 1994;6(3):385–388.
3. Lambertsen RH, Kohn BA, Sundberg JP, Buergelt CD. Genital papillomatosis in sperm whale bulls. J Wildlife Dis. 1987;23(3):361–367.
4. Rewell RE, Willis RA. Some tumours found in whales. J Pathol Bacteriol. 1949;61(3):454–456.
5. Saliki JT, Cooper EJ, Rotstein DS, Caseltine SL, Pabst DA, McLellan WA, Govett P, Harms C, Smolarek KA, Romero CH. A novel gamma herpesvirus associated with genital lesions in a Blainville's beaked whale (Mesoplodon densirostris). J Wildlife Dis. 2006;42(1):142–148.
6. Van Bressem MF, Van Waerebeek K, Piérard GE, Desaintes C. Genital and lingual warts in small cetaceans from coastal Peru. Dis Aquat Organ. 1996;26:1–10.
7. Van Bressem MF, Kastelein RA, Flamant P, Orth G. Cutaneous papillomavirus infection in a harbour porpoise (Phocoena phocoena) from the North Sea. Vet Rec. 1999;144(21):592–593.
8. Van Bressem MF, Van Waerebeek K, Raga JA. A review of virus infections of cetaceans and the potential impact of morbilliviruses, poxviruses and papillomaviruses on host population dynamics. Dis Aquat Organ. 1999;38(1):53–65.
9. Van Bressem MF, Cassonnet P, Rector A, Desaintes C, Van Waerebeek K, Alfaro-Shigueto J, Van Ranst M, Orth G. Genital warts in Burmeister's porpoises: characterization of Phocoena spinipinnis papillomavirus type 1 (PsPV-1) and evidence for a second, distantly related PsPV. J Gen Virol. 2007;88:1928–1933.
10. Van Elk CE, Van de Bildt MWG, De Jong AAW, Osterhaus ADME, Kuiken T. Genital herpesvirus in bottlenose dolphins (Tursiops truncatus): cultivation, epidemiology, and associated pathology. J Wildlife Dis. 2009;45(4):895–906.