Common metastatic carcinoma of California sea lions (Zalophus californianus): evidence of genital origin and association with novel gammaherpesvirus.

Full Abstract

Tissues from 10 adult California sea lions (Zalophus californianus, seven females and three males) that had metastatic carcinoma in sublumbar area lymph nodes were examined histologically. A distinctive epithelial proliferative lesion interpreted as intraepithelial neoplasia was found in genital tracts of all ten animals; in vagina (5/7), cervix (7/7), uterus (3/7), penis (3/3) and prepuce (3/3). Intraepithelial neoplasia closely resembled metastatic carcinomas and was directly contiguous with invasive carcinoma in one animal. Rare eosinophilic intranuclear inclusion bodies were found in penile and preputial intraepithelial neoplasia (one animal), cervical intraepithelial neoplasia (one animal), invasive cervical carcinoma (one animal) and metastatic carcinoma (two animals). Electron microscopic examination of tissues from two sea lions (one with intraepithelial neoplasia and one with metastatic carcinoma) demonstrated viral particles consistent with a herpesvirus. An immunohistochemical stain for the latent membrane protein of Epstein-Barr virus was positive in intraepithelial neoplasia in one sea lion. Herpesvirus DNA sequences were detected by consensus primer polymerase chain reaction (PCR) in metastatic carcinomas from all four sea lions from which unfixed tumor samples were available. Results of sequencing were consistent with a novel gammaherpesvirus in the genus Rhadinovirus. DNA extracted from the four metastatic carcinomas also was tested for papillomavirus by Southern blot and PCR with consensus papillomavirus primers; all samples were negative by both methods. These findings support the genital origin of the sea lion carcinoma and implicate a novel gammaherpesvirus as a possible cause.

Author information

Author/s: Lipscomb, T P (TP); Scott, D P (DP); Garber, R L (RL); Krafft, A E (AE); Tsai, M M (MM); Lichy, J H (JH); Taubenberger, J K (JK); Schulman, F Y (FY); Gulland, F M (FM);

Affiliation: Department of Veterinary Pathology, Armed Forces Institute of Pathology, Washington, DC 20306-6000, USA. lipscomb(-atsign-)afip.osd.mil

Journal and publication information

Publication Type: Journal Article; Research Support, Non-U.S. Gov't; Research Support, U.S. Gov't, Non-P.H.S.

Journal: Veterinary pathology (Vet Pathol), published in UNITED STATES. (Language: eng)

Reference: 2000-Nov; vol 37 (issue 6) : pp 609-17

Dates: Created 2001/02/28; Completed 2001/03/29; Revised 2006/11/15;

PMID: 11105950, status: MEDLINE (last retrieval date: 2/18/2009, IMS Date: )

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