Well-differentiated hepatocellular carcinoma in a ring-tailed lemur (Lemur catta)

Spontaneous neoplasms in captive red-bellied lemurs (Eulemur rubriventer)

Red-bellied lemurs (Eulemur rubriventer: genus Eulemur, family Lemuridae, Suborder Strepsirrhini) are non-human primates endemic to the forests of Madagascar and listed as 'vulnerable' on the IUCN Red List of Threatened Species. Currently, descriptions of neoplasia in this species are extremely scarce, with only one case of hepatocellular adenoma reported. Prosimian submissions received by the Anatomic Pathology Service at North Carolina State University from January 2010 to January 2021 were retrieved. A total of 200 cases of Strepsirrhini prosimians were identified, representing 57 (28.5%) individuals from the genus Eulemur of which seven (12.3%) cases were red-bellied lemurs. Neoplasia was identified in two of the seven (28.57%) cases. The first case was a 25-year-old, intact female with hepatocellular carcinoma and the second a 33-year-old, intact female with a cervical mass consistent with osteoblastic osteosarcoma arising from the left clavicular bone. Hepatocellular neoplasms are commonly reported in prosimians, with carcinomas more frequent than adenomas. In contrast, osteosarcoma has been rarely described in lemuriformes, with four cases reported. To our knowledge, this is the first report of osteosarcoma and hepatocellular carcinoma in a red-bellied lemur.

Hepatocellular carcinomas in captive prosimians

We performed a retrospective examination of spontaneous hepatocellular carcinomas (HCCs) (primary and metastatic tumors) in 14 captive prosimians brought to the Veterinary Medical Diagnostic Laboratory in North Carolina State University over a period of 11 years (2003 to 2014) to characterize the tumors. These animals are endangered primates; a better understanding of the main fatal neoplasms is crucial. In addition to the histologic evaluation, an immunohistochemical study was also performed, using a hepatocyte marker (hepatocyte paraffin 1 [HepPar-1]) and 2 cholangiocyte markers (keratin 7 [K7] and keratin 19 [K19]), in an attempt to identify a specific profile for HCCs with metastatic behavior. Six of the 14 HCCs had pulmonary metastases. The most frequent histopathological findings were a trabecular pattern (14/14, 100%), presence of multinucleated cells (12/14, 85.7%), and foci of extramedullary hematopoiesis (9/14, 64.3%). The mitotic count was significantly higher in the metastatic HCCs (P < .05). HepPar-1 was detected in all primary and metastatic HCCs, with a strong intensity of staining. Labeling for K7 and K19 was positive in 12 HCCs (85.7%) and 1 HCC (7.1%), respectively. Contrary to the less aggressive HCCs, most of the metastatic HCCs (5/6) expressed K7 in more than 15% of cells. The percentage of K7-positive neoplastic hepatocytes was significantly higher in metastatic HCCs. This study suggests that K7 might be a prognostically relevant marker in HCCs of captive prosimians.

Neoplasia in Three Aye-Ayes (Daubentonia madagascariensis)

Tumours diagnosed in three aged captive aye-ayes (Daubentonia madagascariensis), held in two different institutions, are described. A cerebral glioblastoma was diagnosed based on histological and immunohistochemical findings in one of the animals following initial presentation with bilateral mydriasis, absent pupillary reflex, head tilt and ataxia. A second animal was humanely destroyed due to impaired locomotion associated with spondylosis and a post-mortem diagnosis of cholangiocarcinoma was made based on histology with further confirmation with immunohistochemical labelling for cytokeratin 7. A third aye-aye suffering from dental disease was diagnosed with an oral squamous cell carcinoma following an excisional biopsy from a non-healing wound in the lip. Due to progression of the neoplasia the animal was humanely destroyed and post-mortem examination revealed the presence on an additional unilateral phaeochromocytoma.

A RARE CASE OF HEPATOCELLULAR CARCINOMA IN THE ARABIAN SAND CAT (FELIS MARGARITA HARRISONI)

Primary liver cancer is uncommon and is generally classified as hepatocellular carcinoma (HCC), bile duct carcinoma, neuroendocrine (or carcinoid) tumor, and mesenchymal tumor (sarcoma). Here we describe the gross and histopathology characteristics of a rare HCC in a captive Arabian sand cat (Felis margarita harrisoni) held at Al Ain Zoo, United Arab Emirates. The description of this case in the Arabian sand cat adds to the current knowledge of hepatocellular carcinoma in captive nondomestic felids.