Benign Bilateral Adenomyoepithelioma of the Mammary Gland in a Ring-tailed Lemur ( Lemur catta )

A REVIEW OF NEOPLASIA IN PROSIMIANS IN HUMAN CARE FROM 1995 TO 2022

This retrospective study of neoplasia in prosimians in human care reports histologically diagnosed cases from the archives of a nondomestic species pathology service between 1995 and 2022, primarily submitted from zoological institutions. To date, the only prior retrospective study of neoplasia in prosimians, published in 2009, was conducted with cases from a single institution specializing in prosimian noninvasive research and care. In the present study, a total of 153 neoplasms from 109 individuals were identified in the pathology service archives. The most commonly affected species belonged to the Lemuridae (92/109, 84.4%), particularly ring-tailed lemurs (Lemur catta; 55/109, 50.5%), black-and-white ruffed lemurs (Varecia variegata; 19/109, 17.4%), and red ruffed lemurs (Varecia rubra; 14/109, 12.8%). The digestive (49/153, 32.0%), reproductive (35/153, 22.9%), and integumentary (30/153, 19.6%) systems were most commonly affected. Hepatocellular neoplasia was the most common neoplasm overall (35/153, 22.9%), with a large proportion of hepatocellular carcinoma (23/35, 65.7%), suggesting a possible predisposition to this tumor in prosimians. The findings support aggressive behavior of these tumors in prosimians, and a majority (13/23, 56.5%) of cases had evidence of metastasis at the time of submission. Mammary neoplasia was also common (25/153, 16.3%) and predominantly malignant (18/25, 72.0%), in contrast with previous literature, although metastasis was uncommonly reported. The most common integumentary neoplasms were papillomas (12/30, 40.0%), and one report identified squamous cell carcinoma arising directly from a squamous papilloma. Several tumor types are reported herein for the first time in prosimian species, to the authors' knowledge. A literature review identifying additional cases reported since 2009 is also reported. This study contributes a large number of prosimian neoplasia cases to the existing literature to help determine trends in zoological collections and to inform captive prosimian health management.

Aberrant Expression of Cell Cycle Regulator 14-3-3-σ and E-Cadherin in a Metastatic Cholangiocarcinoma in a Vervet Monkey (Chlorocebus pygerythrus)

We present a unique case of metastatic cholangiocarcinoma with concurrent abdominal cestodiasis in an African green monkey (Chlorocebus pygerythrus) that presented with respiratory insufficiency and abdominal discomfort. There were multiple white-grey masses in the liver and colonic serosa alongside intra-abdominal parasitic cysts. Histopathologically, the liver masses were composed of poorly-differentiated epithelial cells that formed densely cellular solid areas and trabeculae. The neoplastic cells were strongly immunopositive for CK7 but negative for Hep-Par1 antigen, which confirmed a diagnosis of cholangiocarcinoma. Interestingly, there was strong and diffuse neoexpression in the tumour of the cell cycle regulator 14-3-3σ, which is not constitutively expressed in normal liver. There was aberrantly strong expression of E-cadherin, a key cell-cell adhesion protein, in neoplastic cells with evidence of cytoplasmic internalization. This is the first immunohistochemical analysis of 14-3-3σ and E-cadherin in a liver neoplasm in an animal species and the use of these markers requires further investigation in animal liver neoplasms.

Scent (Apocrine) Gland Adenocarcinoma in a Wedge-Capped Capuchin Monkey (Cebus olivaceus): Histological and Immunohistochemical Features

In humans, apocrine gland tumours encompass a heterogeneous group of uncommon neoplasms with varied and unpredictable biological behaviour. They can be slow-growing lesions, recur after excision, produce lymph node metastasis in up to 50% of cases or lead to tumour-related death. We document a malignant scent adenocarcinoma in a wedge-capped capuchin monkey (Cebus olivaceus). Immunohistochemical labelling revealed complete absence of myoepithelial cells, a finding usually considered a hallmark of malignancy in humans; however, after a 2-year follow-up, the neoplasm had not recurred. This is the first detailed report of the pathology of a spontaneous scent (apocrine) gland adenocarcinoma in a non-human primate.