Detection of papillomavirus-DNA in mesenchymal tumour cells and not in the hyperplastic epithelium of feline sarcoids

Abstract We examined 12 formalin-fixed paraffin-embedded feline skin tumours which had the histopathological features of fibropapillomas for the presence of papillomavirus (PV) DNA using touchdown polymerase chain recation (PCR), DNA sequencing and nonradioactive in situ hybridization. Nine of the tumours contained a 102-bp PCR product demonstrated using consensus PV primers that amplify a portion of the L1 gene. The nucleotide sequences are closely related, but not identical to that of ovine PV type 2, rabbit oral PV and reindeer PV. The deduced amino acid sequences had strong homologies with the major capsid protein L1 of deer PV, bovine papillomavirus (BPV) 1 and BPV 2, and European elk PV. Although PV antigens were not detected in any of the tumours by immunohistochemistry, PV DNA was demonstrated in individual mesenchymal cells or cell nests of 4/12 tumours by in situ hybridization. A nonproductive infection of mesenchymal fibroblast-like tumour cells with a papillomavirus would explain the lack of PV antigen expression and the absence of PV DNA in the hyperplastic epithelium. Because these tumours and their pathogenesis are similar to equine sarcoids, we suggest that they should be reclassified as 'feline sarcoids' instead of fibropapillomas.     

Amplification of feline sarcoid‐associated papillomavirus DNA sequences from bovine skin

Feline sarcoids are uncommon dermal neoplasms that are thought to be caused by papillomaviral (PV) infection. Feline sarcoid‐associated PV (FeSarPV) has been consistently detected in sarcoids from North American and New Zealand cats but has not been detected within any other feline sample. This suggests that feline sarcoids may develop due to cross‐species infection by a PV from an unidentified reservoir host. While there is some epidemiological evidence to suggest that cattle are the reservoir host of FeSarPV, this PV has never been identified within any bovine sample. In this study both consensus PCR primers and primers specific to FeSarPV were used to investigate the presence of PV DNA within five fibropapillomas and 18 samples of inflammatory skin disease from cattle. Consensus primers amplified bovine PV‐2 DNA from four fibropapillomas, but none of the dermatitis samples. However, specific primers amplified FeSarPV DNA from four fibropapillomas and five inflammatory skin lesions. To the best of our knowledge this is the first time that FeSarPV has been detected within any sample other than a feline sarcoid. The ability of FeSarPV to asymptomatically infect bovine skin suggests that cattle are the reservoir host of this PV and feline sarcoids could be the result of cross‐species infection of a dead‐end host by a bovine PV.     

Expression of connexin 26 and bovine papillomavirus E5 in cutaneous fibropapillomas of cattle

Bovine papillomaviruses (BPVs) can infect epithelial cells and fibroblasts, inducing fibropapillomas in cattle. Gap junctions are communication channels between cells composed of connexins (Cxs). This study evaluated expression of Cx26 and the major BPV oncoprotein E5 in bovine cutaneous fibropapillomas. BPV DNA was amplified from 20/20 fibropapillomas and 3/3 samples of normal skin. All fibropapillomas (20/20) were positive by immunostaining for E5, whereas the three normal skin samples were negative. Cx26 was expressed faintly in the normal skin epithelium. Positive cytoplasmic and juxtanuclear immunoreactivity for Cx26 was evident in 18/20 (90%) fibropapillomas. Western blot analysis demonstrated higher expression of Cx26 in 6/6 fibropapillomas compared to normal skin samples.     

Feline cutaneous fibropapillomas: clinicopathologic findings and association with papillomavirus infection

Twenty-three feline cutaneous fibropapillomas with histologic features similar to equine sarcoids were diagnosed. They were characterized by dermal fibroblastic proliferation with overlying, often ulcerated hyperplastic epidermis. Electron microscopic findings supported the fibroblastic nature of the neoplastic cells. The 23 tumors came from 20 cats and were submitted from veterinary clinics in Wisconsin and Minnesota. These tumors occurred most commonly in young cats and were found primarily on the head, neck, and digits. Fifteen of the 17 cats for which breed was reported were domestic shorthair cats. In 11/20 cases, there was confirmed exposure to cattle. Local recurrence of the tumor following surgical excision was reported in 7 of the 18 cats for which follow-up information was available. Metastasis was not documented in any of the cases. Two of the 19 tumors tested by polymerase chain reaction (PCR) had no amplifiable DNA. The remaining 17 were positive for papillomavirus by PCR. No papillomavirus DNA was detected in three other feline skin tumors (cutaneous mast cell tumor, malignant lymphoma, and fibrosarcoma) that served as controls. This is the first report of detection of papillomavirus in feline tumors that have clinicopathologic features similar to equine sarcoids.     

Malignant melanoma of the eyelid in a red squirrel (Sciurus vulgaris orientis)

A 6-year-old male red squirrel (Sciurus vulgaris orientis) developed bilateral tumors of upper and lower eyelids. The tumors in the left lid recurred despite surgical removal. Necropsy revealed metastasis to the lung. The neoplastic cells were epithelioid and highly pleomorphic, and only a few cells contained melanin granules. Occasionally melanoma cells were immunoreactive for S100, neuron-specific enolase and vimentin, and a small number of cells for cytokeratin. Ultrastructurally, the presence of premelanosomes was confirmed in the cytoplasm. Possible presence of cytokeratin-positive neoplastic melanocytes should be taken into account when differentiating a nonpigmented epithelioid melanoma from other tumors such as anaplastic carcinomas.     

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.     

Tibial plateau leveling osteotomy in a llama with a ruptured cranial cruciate ligament

A 3-year-old 155-kg (342-lb) castrated male llama was examined because of left hind limb lameness of acute onset. A diagnosis of cranial cruciate ligament and medial collateral ligament rupture was made, and tibial plateau leveling osteotomy was recommended. The tibial plateau leveling osteotomy procedure was performed as described for dogs, except that 2 orthopedic plates were used to stabilize the osteotomy because of the size of the llama. The medial collateral ligament was sutured and reinforced with 2 strands of size-2 polypropylene placed in a figure-8 fashion between cancellous bone screws in the femur and tibia. Four days after surgery, failure of the medial collateral ligament repair was evident. Approximately 3.5 years after surgery, the llama was reexamined. The owners reported that the llama had full use of its left hind limb, and only mild lameness (grade 1 of 5) was evident. Results suggest that tibial plateau leveling osteotomy may be applicable in camelids with rupture of the cranial cruciate ligament. However, additional study is needed before tibial plateau leveling osteotomy can be routinely recommended. In particular, additional information is needed on the tibial plateau slope in healthy camelids, the role of the fibula in tibial plateau leveling osteotomy procedures, and the prevalence of cranial cruciate ligament rupture in camelids.     

Radiotherapy of a recurrent ossifying fibroma in the paranasal sinuses of a horse

A 7-year-old female Thoroughbred was admitted with a history of labored breathing, stridor, and exercise intolerance. Examination revealed a mass in the left paranasal sinuses that was determined to be an ossifying fibroma. Initial treatment consisted of surgical removal of the mass alone; however, the mass recurred 9 months after surgery. The mass was again removed, and adjunctive radiotherapy consisting of 3,000 cGy of cobalt radiation was administered. This time, the tumor did not recur for > 6 years. A third surgery was performed to remove the mass, and adjunctive radiotherapy consisting of 4,000 cGy of photon beam radiation from a linear accelerator was administered. The mass did not recur during the subsequent 3 years. Ossifying fibromas are uncommon tumors that frequently recur if incompletely excised. Results in this horse suggest that adjunctive radiotherapy may delay or prevent tumor recurrence in affected horses.     

Entomophthoramycosis conidiobolae in a llama.

A 9-year-old female llama was evaluated for chronic dermatosis involving the external nares. The condition had been diagnosed as a fungal infection. Examination of punch biopsy specimens confirmed the diagnosis of Conidiobolus coronatus. Because of the chronicity of the disease and history of ineffective drug treatment, excision of infected tissue was attempted. Permanent nasal openings were created by suturing the nasal mucosa to the skin after debulking of infected tissue. Excision of most of the infected tissue enabled the llama to breathe easily for 3 years. Because C coronatus does not usually induce deep infections, it may continue to remain dormant in this llama.     

Endobronchial polyp derived from a myxosarcoma in the lung of a dog

An endobronchial polyp was visible radiographically and bronchoscopically in an 11-year-old, mixed-breed dog with a persistent cough. The polyp was removed by traction. Initial histological examination suggested it was a myxomatous fibroma. The cough resolved but recurred with polyp regrowth. Two additional lung masses became visible radiographically. The polyp was removed twice more at 6-month intervals. Euthanasia was performed 15 months after first presentation when coughing recurred soon after the final bronchoscopy. Histological examination revealed that the mass was a myxomatous sarcoma. The lung contained two other unrelated tumors: a bronchioloalveolar carcinoma and a carcinoma of unknown origin.     

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.     

Subclinical copper accumulation in llamas.

A 9-year-old, intact male llama with mild ataxia and generalized malaise of 1 month's duration was euthanized following clinical evaluation. Excessive liver copper concentrations were found in the llama and also in clinically normal herdmates. This case documents multiple animals with increased hepatic stores from standard diets and mineral supplements.     

Gastric squamous cell carcinoma and fascioliasis in a llama

A 5-year-old intact male llama (Llama glama) with gastric squamous cell carcinoma and generalized metastasis is presented. Weight loss, anorexia and cachexia were the presenting clinical signs. Abnormal laboratory findings included neutrophilia, lymphopenia, increased serum activity of hepatic enzymes, mildly increased serum urea nitrogen concentration and elevated protein concentration and nucleated cell count in the peritoneal fluid. Fasciola hepatica ova were identified by fecal sedimentation examination. The presence of flukes, as well as carcinoma metastasis, probably contributed to the increased serum hepatic enzyme activity. Similarities to gastric squamous cell carcinoma in the equine and bovine species are discussed. This case suggests that neoplasia, although rarely reported in the llama, must be considered in the differential diagnostic list for anorexia and weight loss in the llama.     

Malignant nonteratoid ocular medulloepithelioma in a llama (Llama glama).

A 6-year-old female llama presented with buphthalmos of its right eye owing to the presence of an intraocular mass. The affected globe was enucleated and submitted for microscopic examination. The intraocular mass was diagnosed as malignant medulloepithelioma. Within the following months, the llama developed soft tissue masses, which completely filled the right orbital cavity and expanded the cranial portion of the right mandibular bone, and enlarged mandibular lymph nodes. Euthanasia was elected 30 months after the initial diagnosis. The carcass was submitted for postmortem examination, which revealed the presence of medulloepithelioma metastases within the right orbit, mandible, mandibular lymph nodes, lungs, liver, and mesenteric and sublumbar lymph nodes. The primary intraocular tumor and its metastases were composed of neoplastic undifferentiated neuroepithelial cells, which formed tubules, Flexner-Wintersteiner and Homer Wright rosettes, and rare solid sheets. Electron microscopy showed that tumor cells were connected by desmosome-like junctions and contained rare intracytoplasmic basal bodies. Neoplastic cells were positive for vimentin, nestin, microtubule-associated protein 1B, S-100 protein, and glial fibrillary acidic protein (GFAP). To the best of the authors' knowledge, this is the first report of a malignant nonteratoid ocular medulloepithelioma with distant metastases in a llama and of the ultrastructural and extended immunohistochemical characterization of a nonteratoid medulloepithelioma in this species.     

Ventral Abdominal Approach for Laparoscopic Ovariectomy in Llamas

Objective —To evaluate a technique for laparoscopic ovariectomy by a ventral abdominal approach in the llama.
Study Design —Prospective evaluation.
Animal Population —Six healthy adult female llamas, aged 2 to 6 years.
Methods —Laparoscopic ovariectomy was performed with the llamas in a 30-degree Trendelenburg position. The mesovarium and proper ligament of the ovary were isolated, and two Hulka clips were placed in opposite directions across each mesovarium and proper ligament of the ovary. Ovaries were removed through either the instrument cannula or instrument portal.
Results —The ovaries, mesovarium, and proper ligaments of the ovaries were easily identified using laparoscopy by a ventral abdominal approach. The Hulka Clip Applicator was easy to use, and the Hulka Clips provided secure hemostasis of the vessels within the mesovarium. Mean duration of surgery was 35 minutes (range, 17 to 85 minutes). Two llamas were depressed after surgery but improved within 24 hours. No other complications occurred during an 18-month follow-up period.
Conclusions —Laparoscopic ovariectomy in the llama was facilitated by the use of Hulka Clips placed across the mesovarium and proper ligament of the ovary.
Clinical Relevance —Laparoscopic ovariectomy in the llama can be accomplished easily with few complications.     

Multiple recurring uterocervical leiomyomas in two half-sibling Appaloosa fillies

Two yearling, paternal half-sibling Appaloosa fillies were ovariohysterectomized for treatment of multiple uterocervical leiomyomas. The tumors recurred in both fillies, originating from cervical tissue that could not be removed at surgery. Previously reported cases of uterine leiomyoma in the mare have been of solitary tumors in older mares that were treated successfully by surgical removal.     

Bilateral chorioretinitis, centripetal optic neuritis, and encephalitis in a llama

Blindness characterized by dilated, unresponsive pupils and ophthalmoscopic evidence of optic nerve atrophy and retinal degeneration developed in a 5-year-old llama. Lesions were not progressive during 2 months of observation. The llama was euthanatized and necropsied. Histopathologic findings included chorioretinitis, optic neuritis, and encephalitis characterized by mononuclear perivascular infiltration. Attempts to prove an infectious cause were unsuccessful.     

Surgical correction of congenital medial patellar luxation in a llama

Unilateral congenital medial patellar luxation in a young llama was corrected by medial joint capsule release, tibial crest transposition, trochleoplasty, and lateral joint capsule imbrication. The techniques used were the same as described in the dog. One year after surgery, the llama was not lame, but had a valgus deformity originating at the stifle, most likely caused by lateral femoral condyle hypoplasia.