Abstract

In March 1996 a ventral swelling in the urogenital area was observed in an adult male bottlenose dolphin. The male, "Uinik", had been recently collected near the Tabasco coast of Mexico. Physical examination and blood tests revealed a slight regenerative anemia, blood chemistries were normal. There was large ventral swelling in the area near the urogenital opening. Close examination revealed previous shark bite in the area of swelling. Cystocentesis of the swelling revealed large amounts of erythrocytes, epithelial cells, inflammatory cells and the presence of spermatozoa. Subsequent ultrasoundography of the swelling revealed a large cystic structure with some compartmentalization.

During this time it was also noted numerous sublingual nodules were present. A representative sample was biopsied and submitted to the Pathology Department of the School of Veterinary Medicine at the University of Mexico. Histology and electron microscopy diagnosed lymphosarcoma. Ultrasoundography revealed possible hepatic metastasis. Due to the poor prognosis of lymphosarcoma and the difficulty with therapy/monitoring it was decided not to institute chemotherapy. With easy access to the sublingual "neoplastic" lymphoid tissue, samples were submitted to Scripps Research Institute for cell culture. The cultures were unsuccessful. Additional biopsies of the sublingual masses were performed and submitted to the Armed Forces Institute of Pathology, Washington, D.C. They were diagnosed as "marked, reactive lymphoid hyperplasia", however the report did not completely rule out neoplasia.

The ventral swelling remained present with noticeable changing in size, becoming smaller at times and then larger. In late November 1997 the swelling became exceedingly large and two liters of fluid were removed. Bacterial cultures were negative. Again ultrasoundography was performed on the area, studies indicated possible communication between bladder and the cystic structure in question. The bladder was catheterized and sterile new methylene blue was instilled. A continuous negative pressure drain system was introduced to the cyst. The one liter of fluid removed with this method, no evidence of the dye was found. The etiology of the fluid remains unknown. Contrast radiology studies are planned to further study this problem.