Gastric squamous cell carcinoma in three llamas

Fatal septicemia in 2 South American camelids with caudal C3-pyloric-duodenal adenocarcinoma

Gastrointestinal adenocarcinomas are often reported in South American camelids (SAC). We describe here cases of gastroduodenal adenocarcinoma in an adult alpaca (Vicugna pacos) and a llama (Llama glama); both SACs were anorectic and lethargic before death. At autopsy, a prominent and firm caudal C3-pyloric-duodenal junction with stricture and ulceration was present in both animals, as were hemorrhages in various organs and hydrothorax. Microscopically, scattered nests, cords, and tortuous acini of neoplastic epithelial cells were embedded in desmoplastic stroma and invaded the submucosa and muscle layers of the gastroduodenal junction. The mucosa was necrotic, with gram-negative rods in the alpaca and colonies of gram-positive cocci in the llama. No tumor metastases were observed. The neoplastic cells immunolabeled for pancytokeratin. Escherichia coli was isolated from the alpaca and Streptococcus lutetiensis from the llama; septicemia was the cause of death in both animals. Although adenocarcinomas arising from gastric compartments and intestinal segments have been reported in SACs, adenocarcinoma of the caudal C3-pyloric-duodenal junction has not been reported previously in these species, to our knowledge.

Gastric Ulcers in Alpacas— Clinical, Laboratory, and Pathological Findings

Gastric ulcers are a common finding in post-mortem examinations of South American camelids (SAC), but diagnosis in living animals is often difficult. The aim of this study was to provide an overview of the incidence of gastric ulcers in alpacas, common concomitant diseases, and clinical as well as laboratory findings to facilitate diagnosis for veterinarians. For this purpose, a total of 187 necropsy reports of alpacas were evaluated, including clinical and laboratory findings on the living animal. A total of 23.5% of the animals (n = 44) were found to have gastric ulcers, nine were perforated. Compartment 3 was most frequently affected by gastric ulcers. No sex predilection could be detected, but animals 1 year of age and older were more frequently affected by gastric ulcers than animals under 1 year of age. Alpacas with gastric ulcers were presented to the clinic due to different non-specific symptoms. In alpacas with gastric ulcers, significantly more organs or organ systems besides the stomach revealed clinical findings than in animals without gastric ulcers. Of the 44 animals with gastric ulcers, a total of 21 alpacas (47.7%) had a poor nutritional status, but cachexia was not significantly more frequent in animals with gastric ulcers than in other dissected animals without ulcers. Hematologic investigations revealed a significantly lower white blood count and significantly lower segmented neutrophils than in deceased animals without ulcers. Compared to animals discharged after treatment, alpacas that died with gastric ulcers had significantly higher levels of band neutrophils and fewer eosinophils and basophils. Occult blood in feces was found in three of 12 animals with gastric ulcers examined for occult blood. In summary, gastric ulcers are a common problem in SAC, which is difficult to diagnose clinically or by laboratory investigations. As these are often chronic processes involving other organ systems, regular monitoring of the animals' nutritional status and early detection of disease symptoms may help to prevent gastric ulcers.

Neoplasia and Proliferative Lesions of New World Camelids: A Systematic Literature Review and Retrospective Study of Cases Submitted to Colorado State University From 1995 to 2020

Camelid pathology submissions to veterinary diagnostic laboratories are on the rise given the increasing popularity and population of llamas and alpacas especially in the western United States. When compared to other animals, the field of camelid neoplasia has a relative paucity of cases reported in the literature. The Colorado State University Veterinary Diagnostic Laboratories (CSU-VDL) has had a steady increase in the numbers of camelid pathology submissions allowing for a robust review of diagnoses of neoplasia in new world camelids. Here we present a retrospective analysis of camelid neoplastic and proliferative lesions diagnosed at the CSU-VDL from 1995 to 2020, followed by an extensive literature review. Results show increasing incidence of camelid neoplasia reported in the literature, therefore becoming a common diagnosis in llamas and alpacas. Proliferative and neoplastic lesions were diagnosed in 8.8% of new world camelid submissions to CSU-VDL with the most common tumors being lymphomas, squamous cell carcinomas, fibromas, and adenocarcinomas. Risk factors are female sex and increased age except in the case of lymphoma, which tends to occur in younger camelids. Lymphomas, melanomas, and adenocarcinomas (especially of gastrointestinal tract) carry an increased risk of multiple-organ system involvement often with widespread metastases. Conditions described in camelids for the first time include osteosarcoma, cutaneous hemangiosarcoma, myxosarcoma, pilomatricoma, ovarian theca cell tumor, congenital nevus with malignant transformation, and various other neoplasia. This article will provide an operational guide for camelid neoplasia to further assist veterinary laboratory diagnosticians, researchers, and practicing veterinarians in the field of camelid medicine and pathology.

Metastatic cholangiocarcinoma in a llama (Lama glama)

A 2-year-old female llama ( Lama glama), from a private zoological park, with anorexia, ataxia, dyspnea, ascites, and emaciation, was necropsied. Gross inspection, and cytological, histological, and immunohistochemical analyses were performed. A firm, white, multinodular mass, 25 cm in diameter was found in the liver parenchyma. Similar nodules up to 3 cm were found in lymph nodes, lung, diaphragm, and peritoneum. Histologically, the affected organs were replaced by an infiltrative growth of undifferentiated neoplastic cells. Immunohistochemically, neoplastic cells were positive for pancytokeratin (panCK), CK20, and CK19, and negative for thyroid transcription factor 1, CK7, and carcinoembryonic antigen. A diagnosis of poorly differentiated metastatic cholangiocarcinoma was made.

Prevalence of neoplasia in llamas and alpacas (Oregon State University, 2001-2006)

Prevalence and type of neoplastic disease were determined in 551 camelid submissions (368 alpacas [Lama pacos], 180 llamas [Lama glama], and 3 cases in which species was not identified) over a 5-year period. Forty neoplasms were identified in 38 animals (6.9%). Prevalence of neoplasia in llamas was higher (11%) than in alpacas (4.9%). Mean age of camelids with neoplasia was 9.42 +/- 4.9 years. Mean age of alpacas with neoplasia (5.48 +/- 3.7 years) was significantly less than of llamas with neoplasia (12.53 +/- 3.2 years; P < 0.001). Cutaneous and mucocutaneous fibroma/fibropapilloma was most common (10 animals), followed by cutaneous and mucocutaneous squamous cell carcinoma (6 animals), disseminated lymphoma (5 animals), and fibrosarcoma (4 animals). Four of 5 animals with lymphoma were alpacas, aged 0.21 to 4 years. Lymphoma occurred in 1 aged llama (15 years). Disseminated carcinoma and adenocarcinoma occurred in 4 llamas and 2 alpacas, and included biliary (2), gastrointestinal (2), mammary gland (1), and unknown (1) origin. Mean age of camelids with any type of carcinoma or adenocarcinoma (12.36 +/- 2.8 years) was significantly greater than that of camelids with lymphoma (4.24 +/- 6.2 years; P = 0.02). Results indicate that neoplasia is relatively common in camelids and that there are differences between llamas and alpacas as regards prevalence of neoplasia, tumor types, and age at diagnosis.

Pulmonary neoplasia in two llamas (Lama glama)

Two llamas with pulmonary tumors were examined. Llama No. 1 had multiple nodules throughout the lung that consisted histologically of solid clusters of polygonal to spindle cells with rare glandular differentiation. Intravascular emboli were common. Similar neoplastic masses were present in the kidney, heart, and liver. Immunohistochemically, neoplastic cells were positive for broad-spectrum cytokeratins (CKs), high-molecular weight CKs, CKs 5/6, and vimentin. The diagnosis was pulmonary carcinoma. Llama No. 2 had pulmonary nodules without extrapulmonary involvement. Microscopically, neoplastic cells formed acini lined by simple epithelium and solid cords of squamous cells that sometimes surrounded acini. Neoplastic cells were strongly positive for broad-spectrum CKs and weakly positive for thyroid transcription factor-1. The diagnosis was adenosquamous carcinoma. Pulmonary tumors account for 23% of neoplasms in South American camelids in our laboratory, making this the second most common type of neoplasm after lymphosarcoma.

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.

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.

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.