Intraocular melanoma in an alpaca

Concurrent Clostridial Enteritis and Oviductal Adenocarcinoma with Carcinomatosis in an Adult Alpaca (Vicugna pacos)

An adult alpaca (Vicugna pacos) with a history of colic and anorexia was euthanized because of failure to respond to treatment. Macroscopically, pale-tan, multifocal to coalescing, firm nodules and plaques markedly expanded the omentum, mesentery and the parietal and visceral peritoneum of multiple abdominal organs, especially the right oviduct and associated mesosalpinx. Abundant dark-red watery digesta were present in the duodenum and jejunum. Histological evaluation of the right oviduct, abdominal visceral nodules and plaques and mesenteric lymph nodes revealed transmural expansion and replacement by an epithelial malignant neoplasm, comprised of tubules and acini of ciliated columnar cells supported by abundant fibrous connective tissue. Both ovaries were histologically normal. On the basis of the ciliated morphology of the neoplastic cells, the focus on the proximal reproductive tract and the unremarkable ovaries, a reproductive tubal adenocarcinoma with carcinomatosis was diagnosed, with both the endometrium and oviduct considered as the tissues of origin. The prominent ciliated morphology of the neoplastic cells and the classification of human fallopian tube (oviduct) neoplasia lead us to propose oviductal adenocarcinoma with widespread carcinomatosis as the definitive diagnosis. The lamina propria of the small intestine was infiltrated segmentally by lymphocytes, plasma cells and neutrophils, and Clostridium perfringens with beta2 toxin production was identified by polymerase chain reaction in the small intestinal contents. To our knowledge, this is the first report of these two distinct diseases in an alpaca.

Melanocytic Ophthalmic Neoplasms of the Domestic Veterinary Species: A Review

Melanocytic neoplasms in veterinary species occur in various ophthalmic locations including the eyelid, conjunctiva, cornea, sclera, anterior and posterior uvea, and orbit. Histology usually provides the definitive diagnosis for melanocytic ocular neoplasias. The degree of tissue invasiveness and anaplastic cellular characteristics are more reliable indicators of biological behavior than is mitotic index in most ophthalmic melanocytic tumors. Melanocytic neoplasias of the eyelid are predominantly benign in canines and equines, though in felines, there is the potential for metastasis, especially if the conjunctiva is involved. Limbal melanocytic tumors are predominantly benign in all the studied species, though there is a bimodal occurrence with this tumor type in canines, where those that appear in dogs younger than 4 years tended toward active growth, whereas those that appear in dogs older than 8 years tended to progress more slowly, and may not require therapy. The most common location for melanocytic ocular neoplasias in both canines and felines is the anterior uvea. Feline diffuse iris melanoma in particular has a higher incidence of metastasis than does canine nodular anterior uveal melanocytoma. In contrast, posterior uveal melanocytic tumors are rare in both canine and feline species and are considered benign. Orbital melanoma is rare in both canine and feline species; however, it generally carries a grave prognosis owing to its malignant nature. Knowledge of the general biological behavior and its variability among locations within the eye and between species is essential in therapeutic planning.

Immunohistochemical characterization of perineal melanoma in Kilis goats

We describe the clinical, histopathological and immunohistochemical features of the malignant melanomas in the perineal regions of Kilis goats from Sanliurfa province in Turkey. We studied 13 female Kilis goats between 3 and 8 years old that were brought to Harran University Veterinary School, Department of Surgery, between 2002 and 2010. By macroscopic examination, the masses were determined to have elastic consistency, dark brown-black color, necrotic surfaces and ulceration. Microscopically, pleomorphic cells were observed under the basal layer and these advanced toward the dermis. These cells were polyhedral, round or spindle-shaped, anaplastic, and their cytoplasm contained varying amounts of dark brown-black pigments. Immunohistochemical staining was obtained with anti-melan A, vimentin and S100 antibodies.

Ophthalmology of South american camelids

In the past 10 years, information about South American camelid anatomy, physiology, medicine, and surgery has increased exponentially, including information about the eye. Although trauma-related diseases are the most common eye problems for which camelids are presented to veterinarians, there have recently been many anecdotal reports and published case reports of camelids having ocular malignancies and potentially hereditary ocular abnormalities. The increased number of ocular diseases being reported may be because of increased recognition of camelid diseases or an increase in these diseases as a result of restricted gene pools as a consequence of inbreeding. As the popularity of camelids is steadily increasing, owners are becoming more knowledgeable about their animals, and there is more need for veterinarians who understand their ocular anatomy, physiology, disease susceptibility, and recommended treatments. This article provides the relevant information about the eye.

Metastatic malignant melanoma in an alpaca (Vicugna pacos)

A case of malignant melanoma in a 7-year-old, intact, black, male Huacaya alpaca with a history of a chronic, nonhealing wound involving the left external nostril, weight loss, and inappetence is described. Malignant melanoma was diagnosed by histology of punch biopsy specimens from a mass on the maxilla associated with the nonhealing wound and from a mass in the submandibular region. The alpaca was humanely euthanized 10 days after the diagnosis on the basis of the poor prognosis and rapid clinical deterioration. At postmortem examination, the alpaca had an ulcerated, multilobulated, black pigmented mass (8.0 cm x 6.0 cm x 4.0 cm) that infiltrated the left rostral maxilla extending into the marrow space and into the left nasal cavity. Numerous, discrete, coalescing masses were present in the subcutaneous tissue of the submandibular area, peritracheal connective tissue, pericardium, and diaphragmatic parietal pleura and were disseminated throughout the pulmonary parenchyma. The masses were diffusely black on cut surface and exuded black pigment. Histologically, all masses were composed of spindloid to polygonal cells with indistinct cell borders and moderate amounts of cytoplasm that contained abundant fine, black granules (melanin), confirming metastasis of a primary mucocutaneous melanoma. To the authors' knowledge, this is the first report of a malignant melanoma involving bone in a New World camelid.

Osteogenic Intraocular Melanoma in an Alpaca (Vicugna Pacos)

A 10-year-old, female, pregnant alpaca ( Vicugna pacos) presented with a discolored, swollen right eye. The eye did not respond to treatment and was enucleated. Sectioning of the fixed eye revealed an ocular mass replacing the aqueous and vitreous humors, with multiple regions of bone formation. Histopathological, immunohistochemical, and transmission electron microscopy confirmed the tumor was an intraocular melanoma with bone formation. Osteogenic melanoma is a rare variant of melanoma not reported in the eye before.

Malignant neoplasia in four alpacas

Malignant neoplasia in 4 alpacas was characterized by acute onset of clinical signs and rapidly deteriorating condition. Postmortem examination revealed metastatic or multicentric neoplasia in the abdominal organs of alpacas 1, 3, and 4 and an extensive thoracic mass in alpaca 2. Immunohistochemical stains supported a diagnosis of B-cell lymphosarcoma in alpacas 1-3 and a neuroendocrine neoplasm in alpaca 4.

A comparative review of melanocytic neoplasms

Melanoma is a devastating disease frequently encountered within both veterinary and human medicine. Molecular changes linked with neoplastic transformation of melanocytes include mutations in genes that encode proteins intrinsic to the regulatory pathways of two tumor suppressor proteins (retinoblastoma protein and p53), proto-oncogene mutation to oncogenes, altered expression of epithelial cadherin and CD44 adhesion molecules, and upregulation of angiogenic factors and other growth factors. Histologic evaluation of the primary mass is the most common means of diagnosis, with cytology used more frequently to document metastasis. Melanoma's highly variable histologic and cytologic patterns can make diagnosis by either method problematic. Adherent epithelioid morphology, including signet ring forms, and nonadherent round and spindle forms are recognized, with pigmentation an inconsistent finding. The site of the tumor, the thickness of the primary tumor or depth of invasion, and the number of mitotic figures per high-power field or per millimeter are used histologically to predict biologic behavior, whereas site and degree of pleomorphism are typically used for cytologic preparations. Diagnosis of amelanotic melanoma can be aided by ancillary diagnostic techniques. Tumor cells are usually positive for vimentin, S100, neuron-specific enolase, and Melan-A, and negative for cytokeratin. Melan-A as a positive marker is not as sensitive as the others are but is likely more specific. Monoclonal antibodies to human melanosome-specific antigens 1 and 5 cross-react with canine antigens for a combined sensitivity rate of 83%. Mouse monoclonal antibody IBF9 specifically recognizes canine melanoma antigen and also has good sensitivity. Serologic markers, including cytokines, cell adhesion molecules, and melanoma-inhibitory activity, are being investigated as potential sentinels of melanoma. Currently, there is no single diagnostic technique capable of differentiating benign from malignant melanocytic neoplasms or predicting survival time.