CLINICAL CHALLENGE

History: A 5-yr-old male greater bush-baby (Oto/emur garnettii) was presented tothe Veterinary Teaching Hospital, KansasState University, for evaluation of unilat-eral proptosis of 5 days duration and mod-erate chronic weight loss. The owner ini-tially noticed conjunctivitis 4 wk before andhad attributed it to possible trauma fromits two cagemates.

On presentation, the bushbaby was de-pressed and approximately 7% dehydrated.The right eye protruded 1em from the orbit;conjunctivitis, corneal perforation, and irisprolapse were evident (Fig. 1). Purulent dis-charge was noted from the right nostril. In-traoral examination was performed underketamine/acepromazine/isofiurane anes-thesia, revealing a pink/tan mass that dis-placed the right maxillary premolars and

Journal of Zoo and Wildlife Medicine 25(3): 472-475, 1994Copyright 1994 by American Association of Zoo Veterinarians

molars. Abdominal and lymph node pal-pation was unremarkable. Thoracic and ab-dominal radiographs and fundic examina-tion were completed and showed noabnormalities. Survey radiographs of theskull (Figs. 2 and 3) were obtained. Perti-nent hematologic and serum chemistryfindings included WBC = 18,5001,ul (refer-ence range, 11,200 ± 7001,ul); RBC = 5.51x 1061,ul (9.3 ± 0.21,ul); Hgb = lOA g/dl(16 ± 0.3 g/dl); PCV = 29% (49.1 ± 0.8%);MCV = 53.1 fl (53.2 ± 0.7 fl); neutrophils= 14,9851,ul (4,514 ± 3251,ul); lymphocytes= 3,3301,ul (5,981 ± 358/,ul); total protein= 5.0 g/dl (7.2 ± 0.1 g/dl); and albumin =2.1 g/dl (4.0 ± 0.1 g/dl).'

Please make your diagnosis using Figures2-4 before continuing.

Figure 1. Proptosis in an adult male greater bushbaby iOtolemur garnettii), postmortem.

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CLINICAL CHALLENGE 473

Figure 3. Left 20° ventral right dorsal oblique skullradiograph of the greater bushbaby.

Figure 2. Ventrodorsal skull radiograph of the great-er bushbaby.

Figure 4. Microscopic appearance of the oral cavity of the greater bushbaby, postmortem. Notice haphazardarrangement ofioosely spaced neoplastic cells within the submucosa (S). The overlying mucosa has focal vacuolardegeneration and erosion (arrows). H&E, bar = 50 /Lm.

474 JOURNAL OF ZOO AND WILDLIFE MEDICINE

Diagnosis: Right maxillary fibrosarcomaresulting in ocular disease.

Discussion. The hematologic abnormal-ities in this case were most likely attribut-able to chronic low-grade inflammation,with resultant normocytic anemia and ma-ture neutrophilia. Radiographs revealed os-teolysis of the right lateral maxilla, zygo-matic process, and zygomatic bone, with noidentifiable periosteal reaction; the teethwere displaced laterally and ventrally by asoft tissue mass filling the osteolytic area.Histologically, the mass was composed oflarge numbers of widely spaced spindle cellson a loose fibrous and slightly mucinousbackground; three to five mitotic figures wereseen per 400 x field (Fig. 4). Diagnosis ofthis mass as a fibrosarcoma relied heavilyupon its histopathologic characteristics. Be-cause of the poor prognosis for successfulremoval of this tumor, the owner electedeuthanasia.

On postmortem examination, the o~almass was well circumscribed and soft, WItha slightly mucinous appearance. The massextended through the right nasal turbinates,although it did not cross the nasal septumor invade intraocular tissue. There was noevidence of metastasis of this fibrosarcoma.Corneal ulceration and perforation and irisprolapse in this bushbaby were secondaryto exposure resulting from pressure from thegrowing maxillary fibrosarcoma.

Oral neoplasia has rarely been reportedin primates, and has not been previouslyreported in prosimians.r-'>" Comparativeclinical diagnosis of maxillary masses in anyspecies would include neoplasia (fibrosar-coma, malignant melanoma, and squamouscell carcinoma being most often reportedacross species), mycotic or bacterial abscess,or granulomatous disease. Diagnosis is bestaccomplished by histopathologic examina-tion of a wedge or core biopsy. Althoughthe cells present in many of these differentialdiagnoses may be collected by fine needleaspirate, sarcoma cells are typically difficultto collect by that method alone."

The current treatment of choice for fibro-sarcoma in domestic species involves sur-gical excision with margins of at least 2-3em; this approach was not possible for this0.9-kg bushbaby. Even if radical surgicalexcision had been feasible, it would notguarantee a permanent cure. In domesticdogs and cats, 10-30% of fibrosarcoma sitesshow recurrence and/or metastasis after ex-cision." Chemotherapeutic regimens such asdoxoru bicinl cyclophosphamide com bina-tions (with or without radiotherapy and hy-perthermia) do show some benefit in do-mestic species by retarding the recurrenceof lesions" and therefore should be consid-ered as possible therapeutic options for an-imals in zoological collections.

This report was submitted by Lisa Har-renstien, D.V.M., and James W. Carpenter,M.S., D.V.M., Department of Clinical Sci-ences, and Sharon Gwaltney, D.V.M., Ph.D.,Department of Veterinary Diagnostic In-vestigation, College of Veterinary Medi-cine, Kansas State University, Manhattan,Kansas 66506, USA. We thank Drs. JanetteAckermann, Alan H. Brightman, Harriet J.Davidson, and James J. Hoskinson for theirdiagnostic assistance.

LITERATURE CITED

1. Brack, M. 1985. Tumors in dwarfgalagos (Ga-lagoides demodoviii. Vet. Pathol. 22: 344-346.

2. DePaoli, A., and H. M. McClure. 1982. Gas-trointestinal neoplasms in nonhuman primates: a re-view and report of eleven new cases. Vet. Pathol.19(5uppl. 7): 104-125.

3. Griesemer, R. S., 1. S. Manning, and L. Newman.1973. Neoplasms in galagos. Vet. Pathol. 10: 408.

4. Izard, K., S. Heath, Y. Hayes, and E. Simons.1991. Hematology, serum chemistry values, and rectaltemperatures of adult greater galagos (Galago garnettiiand Galago crassicaudatus). J. Med. Primatol. 20: 117-121. .

5. McClure, H. M. 1980. Neoplastic diseases innonhuman primates: literature review and observ~-tions in an autopsy series of2176 animals. In: Montali,R. 1., and G. Migaki (eds.). Comparative Pathology ofZoo Animals. Smithsonian Institution Press, Wash-ington, D.C. Pp, 549-565. .

6. Montali, R. J. 1980. An overview of tumors in

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zoo animals. In: Montali, R. J., and G. Migaki (eds.).Comparative Pathology of Zoo Animals. SmithsonianInstitution Press, Washington, D.C. Pp, 531-542.

7. Seibold, H. R., and R. H. Wolf. 1973. Neo-plasms and proliferative lesions in 1065 nonhumanprimate necropsies. Lab. Anim. Sci. 23: 533-539.

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8. Withrow, S. J., and E. G. MacEwen. 1989. Clin-ical Veterinary Oncology. Lippincott, Philadelphia,Pennsylvania.

Receivedfor publication 25 August 1993.