Retinoblastoma in the eye of a llama (Llama glama)

ANIMAL STUDIED: A 6-year-old, pregnant female llama experienced a 6-month history of epiphora, buphthalmos, and acute loss of vision in the left eye. The condition was unresponsive to topical antimicrobial and anti-inflammatory therapy and progressed to corneal rupture. PROCEDURES: Transpalpebral enucleation was performed and an intraorbital silicone prosthesis was implanted. The eye was fixed in formalin and processed according to routine paraffin technique. Sections of a mass were immunohistochemically prepared routinely and stained for glial fibrillary acidic protein (GFAP), S-antigen, and rhodopsin. RESULTS: Gross, histopathologic, and immunohistochemical analysis revealed a retinal tumor consistent with a retinoblastoma. The neoplastic tissue formed Flexner-Wintersteiner and Homer-Wright rosettes, originated from the retina, and demonstrated photoreceptor differentiation with S-antigen and rhodopsin expression. Neoplastic cells were negative for GFAP. Four years after enucleation, the llama showed no signs of recurrent neoplasia. CONCLUSIONS: This report describes the diagnosis and successful treatment of the first known retinoblastoma in a llama.     

Malignant teratoid medulloepithelioma in a llama

A lesion was identified in the eye of a juvenile llama, and preliminary clinical findings included anterior uveitis and an exudative retinal detachment suggestive of infectious disease. However, histopathologic evaluation of the enucleated globe revealed an intraocular neoplasm composed of primitive neuroepithelium forming ribbons, cords, and rosettes, heteroplastic elements including spindle cells in a loose myxomatous matrix, and islands of well-differentiated hyaline cartilage. Immunohistochemically, neoplastic cells were positive for vimentin and neuron-specific enolase. Spindle cells were multifocally positive for desmin and muscle specific actin, indicating differentiation towards myofibers. These findings are consistent with a diagnosis of malignant teratoid medulloepithelioma, an extremely rare ocular neoplasm that affects children and young animals.     

Cryptococcosis in a llama (Lama glama).

Cryptococcosis was diagnosed in a 17-year-old male llama that had been euthanatized following an acute onset of neurologic disease. Tissues affected included the brain, spinal cord, lung, and kidney. The character of the leukocytic response varied from minimal to pyogranulomatous. Cryptococcosis has not been previously reported in a llama, although the infection has been described in 2 other species of New World camelids. The pathogenesis of cryptococcosis is briefly reviewed.     

Metastatic pulmonary adenocarcinoma in a llama (Lama glama).

An adult female llama with a comminuted fracture of the left femoral head was necropsied. A firm multinodular mass infiltrated skeletal muscle adjacent to the fracture. Multiple, firm, white nodules were in the pulmonary parenchyma and pleura. A single nodule was in the liver. Microscopically, transition from nonneoplastic bronchiolar epithelium to neoplastic epithelium that formed acinar structures was evident at bronchioloalveolar junctions. A diagnosis of pulmonary adenocarcinoma was made. Similar neoplastic tissue was in the liver and in the perifemoral mass. Immunohistochemically, neoplastic cells were positive for pan-cytokeratin, cytokeratin 7, and cytokeratin 5/6 antibodies and negative for vimentin and cytokeratins 8/18 and 20.     

Keratinizing ameloblastoma in a 9-month-old llama (Lama glama).

A 9-month-old male llama (Lama glama) was presented because of a rapidly growing mass on the right side of the face. Radiographs revealed a marked expansion of the right caudal face region with bone lysis involving the maxilla and the nasal, lacrimal, zygomatic, and palatine bones. Cytologically, the mass consisted of atypical round to polygonal cells with round nuclei and basophilic cytoplasms that formed acini and rows. Histologically, the mass consisted of anastomosing cords and sheets of neoplastic odontogenic epithelial cells embedded in a loose fibrovascular connective tissue. Single layers of peripheral, polarized, palisading, columnar epithelial cells were seen at the edges of some cords. Within the centers of the cords, epithelial cells showed rapid progression to keratin production. The histologic diagnosis was keratinizing ameloblastoma. Ameloblastomas are neoplasms of odontogenic epithelium that tend to be locally aggressive and can cause substantial destruction of bony structures. Because ameloblastomas do not tend to metastasize, they can be successfully treated by complete surgical excision, performed before extensive bony destruction occurs. Ameloblastoma, although expected to be rare, should be onthe list of differential diagnoses for facial swelling in llamas.     

Cecal impaction due to dysautonomia in a llama (Lama glama).

A llama (Lama glama) died after 1 wk of obstipation, lethargy, and rolling. Necropsy showed that the stomach and small intestine were distended with gas and fluid. The cecum was impacted with dry contents and the colon was empty. No gross lesions were found in the wall of the gastrointestinal tract or other organs. Histologic changes consisted of chromatolysis of neurons of autonomic ganglia, enteric plexi, and the accessory cuneate nucleus, consistent with lesions associated with dysautonomia in other domestic animals.     

Gross and microscopic lesions of polioencephalomalacia in a llama (Lama glama).

A 14-wk-old female llama (Lama glama) developed progressive neurologic disease characterized by stiff gait, circling, decreased mentation, and seizures. At necropsy, lesions were limited to the brain and consisted of bilateral necrosis of the cortical gray matter of the occipital lobes of the cerebral cortex. The primary microscopic alteration was bilateral laminar cerebrocortical necrosis, affecting mainly the deep laminae. Clinical disease, and gross and microscopic lesions were consistent with those of polioencephalomalacia.     

Cutaneous Melanocytoma in a Llama (Lama glama)

Veterinary Research Communications -     

Compressive myelopathy due to intervertebral disk extrusion in a llama (Lama glama).

A 12-year-old intact female llama was euthanized following acute onset of spastic tetraparesis and recumbency with inability to rise. Postmortem examination revealed caudal cervical spinal cord compression due to a mass within the ventral spinal canal arising from the C6-C7 intervertebral disk space and attached to an irregularly thickened annulus fibrosis. On histopathologic examination, the mass was composed of amorphous acellular basophilic to amphophilic material admixed with irregularly arranged collagen bundles. The amorphous material was metachromatic and contained multiple small foci of markedly vacuolated round cells, characteristic of origin from the nucleus pulposus. Severe necrosis of all white matter tracts with astrocytic reaction was present in the overlying spinal cord segment. Ascending and descending Wallerian degeneration and dissecting interstitial astrogliosis were present within white matter tracts above and below the lesion, respectively. The diagnosis was compressive myelopathy due to chronic extrusion of the nucleus pulposus of the C6-C7 intervertebral disk. To the authors' knowledge, this is the first report of intervertebral disk disease in a camelid.     

Pestivirus infection in a llama (Lama glama)

Cattle, sheep, goats and a llama (Lama glama) were among several animals that were grazed at our isolation facility. The llama was introduced about 20 months ago and about 12 months later a cow and its calf, both persistently viraemic to bovine virus diarrhoea virus (BVDV), were also introduced. On several occasions during the last 12 months, the llama and the BVDV viraemic cattle were grazed in adjacent paddocks.     

Intraocular nematodiasis in a llama (Lama glama)

This report describes a unique case of presumed migration of Parelaphastrongylus tenuis through the spinal cord into the eye of a llama where it survived and matured within the ocular environment. Blindness of the eye was most likely attributable to migration of the parasite through the central nervous tissue.     

Coccidioides posadasii keratouveitis in a llama (Lama glama)

A 7-year-old male llama was examined for a 3-month history of weight loss, and unilateral keratouveitis. Clinical examination revealed nonulcerative corneal stromal abscessation, corneal vascularization, corneal edema, miosis, posterior synechia, cataract, and fibrin in the anterior chamber of the right eye. The left eye was normal. Histopathology of the right eye following enucleation revealed pyogranulomatous keratouveitis with intralesional fungal spherules consistent with Coccidioides spp. PCR amplification with DNA sequencing confirmed Coccidioides posadasii infection. To the authors' knowledge, this is the first reported case of ocular coccidioidomycosis in a llama.     

Ultrasonography as an aid to controlled breeding in the llama (Lama glama).

An ultrasonic linear array scanner with a transrectal probe was used to observe ovarian and uterine changes associated with the reproductive cycle in llamas. 'Waves' of follicular development and regression occurred in unstimulated females, during which the dominant follicle reached a maximum size of 9 to 13 mm; both ovaries were equally active. Ovulation was induced by mating in 80 per cent of cases, and when mating was accompanied by the administration of human chorionic gonadotrophin the ovulation rate increased to 90 per cent and the time to ovulation decreased from two to three days to one to two days. Some spontaneous ovulations occurred. Corpora lutea reached a maximum size of 12 mm (non-pregnant) or 14 mm (pregnant) after seven or 16 days, respectively. The lifespan of the corpus luteum was approximately 11 days in non-pregnant llamas and the regression time was advanced by the administration of prostaglandin or embryo recovery. Pregnancy could be diagnosed as early as 19 days after mating.     

Cryopreservation of Llama (Lama glama) Semen

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In order to test two extenders, and the effect of the addition of a surfactant and different freezing rates for cryopreservation of llama semen, the motility (MOT) and the integrity of acrosomes (NA) of 11 frozen ejaculates, collected with artificial vaginas from three llama males, were recorded. According to a 2 × 2 × 2 factorial design, the semen had been split and diluted comparatively with TRIS- and EDTA-extenders prepared, respectively, with and without 0.5% Equex STM and the samples frozen simultaneously 2 cm and 10 cm above the level of liquid Nitrogen. MOT of frozen-thawed semen was significantly better (p < 0.05) with TRIS-extender, although no difference for NA was recorded. The addition of surfactant as well as the compared freezing rates had no significant effect on MOT or NA. It was concluded that TRIS-extender may be promising for further fertility trials of cryopreserved semen, but centrifugation of prediluted semen would probably be necessary to get a minimum amount of sperm into the straws used as insemination doses.     

Surgical treatment of uterine torsion in a llama (Lama glama)

A multiparous llama was presented because of failure to proceed into the second stage of labor. Clockwise uterine torsion and a live fetus were identified by rectal and vaginal examinations. A cesarean operation was elected because of the prolonged first stage of labor and lack of cervical dilatation. Anesthesia was induced with a 10% guaifenesin solution administered intravenously via a pressurized pump followed by intubation and maintenance with 2% halothane. A ventral midline surgical approach exposed the uterus and the fetus was removed through a uterotomy. The placenta was manually stripped from the myometrial edges of the incision and the margins were oversewn using a continuous interlocking pattern. The uterus was then closed using a continuous Utrecht pattern and the uterus rotated 180 degrees back to its normal anatomical position. The abdomen was closed in 3 layers. Recovery of the llama was uneventful with the male cria able to nurse 6 hours post-operatively. Placental expulsion occurred approximately 48 hours after fetal removal.     

Malignant teratoid medulloepithelioma in a horse

Enlargement of the left eye, corneal opacification, and blindness were clinical signs of a teratoid medulloepithelioma in a 5-year-old Standardbred mare. Diagnosis was made on histologic examination of the enucleated eye. Medulloepitheliomas are congenital intraocular tumors arising from primitive ciliary body epithelium. Their development is rare in domestic animals.     

Congenital cataracts and persistent hyaloid vasculature in a llama (Lama glama)

A 9-month-old llama was evaluated for apparent blindness. Bilateral cataracts were diagnosed and cataract surgery was performed on the right eye. At the time of surgery persistent hyperplastic primary vitreous, persistent hyperplastic tunica vasculosa lentis, and a persistent hyaloid artery were observed. Prior to surgery Power Doppler ultrasound revealed a patent tunica vasculosa lentis OS. Despite reports of a poor success rate for llama cataract surgery, through use of careful tissue handling, phacoemulsification, viscoelastic endothelial protectants, anti-inflammatories, and BSS-Plus irrigating solution, vision was successfully restored in both eyes of the llama.