Tumor occurrence in wild mammals is reportedly very low. euthanized nutrias from the eradication campaign of the Korean Ministry of the Environment were brought to our laboratory for necropsy. One of these nutrias (sex: male, body weight: 7.5 kg, body length: 98 cm) had a large mass in the inguinal region, adjacent to the penis. The oval-shaped mass was larger than 6 SR 146131 3 cm and exhibited yellowish exudate (Fig. 1). For microscopic examination, the mass was fixed in 10% neutral buffered formalin and processed in a routine manner with a graded ethanol series and xylene. The mass was then embedded in paraffin wax, sectioned at 4 m, and stained with hematoxylin and eosin (H&E). For immunohistochemistry (IHC) analysis, monoclonal anti-adipophilin antibody (sc-377429; Santa Cruz Biotechnology, USA) was used to detect sebaceous cells. Hydrogen peroxide solution (3%) was NFKB1 used to inhibit endogenous peroxidase activity. The antigen-antibody complex was labeled with an avidin-biotin peroxidase complex solution (Vector Laboratories, USA) and a DAB substrate kit (Invitrogen, USA). Slides were then counter-stained with Mayer’s hematoxylin. Sectioned slides of canine cutaneous sebaceous gland adenoma were used as positive control for adipophilin staining. Open in a separate window Fig. 1 Necropsy of a male wild nutria. (A) The ventral aspect of the animal. The ventral skin has been peeled back, revealing a big muscle-covered mass (asterisk) lateral towards the male organ (arrow). (B) Cut surface area from the mass. Yellowish exudates are found. Microscopically, the mass was made up and well-demarcated of reserved basal SR 146131 cells and secretory cells, which contained an waxy and greasy matter that comprised a kind of sebaceous gland. The gland got an extended excretory duct with a broad lumen lined by hyperplastic squamous epithelium. The excretory ducts demonstrated a number of shapes and sizes; occasionally, these were filled up with keratinized cell particles (Fig. 2A). The tumor cells got a central circular nucleus with one or (hardly ever) 2 huge nucleoli. The cytoplasm included lipid vacuoles of varied sizes (Fig. 2A and B). Hyperplastic basal cells encircled the foci from the sebaceous cells typically, forming lobulations of varied sizes. Mitotic figures were noticeable occasionally. Infiltration of mononuclear inflammatory cells around secretory ducts was seen in some certain specific areas. To verify the identity from the sebaceous cells, anti-adipophilin was useful for IHC. Adipophilin can be an adipocyte differentiation-related proteins indicated in intracytoplasmic lipid droplets of sebocytes ; right here, it was indicated in the cytoplasmic lipid vacuoles of sebocytes, however, not in basal cells (Fig. 2D). As a complete consequence of these results, preputial gland adenoma was diagnosed with this crazy nutria. Open up in another home window Fig. 2 Microscopic study of the mass inside a man crazy nutria. (A) The mass comprises reserved basal cells and secretory cells containing greasy and waxy matter, which constitute a kind of SR 146131 sebaceous gland. The gland includes a lengthy excretory duct with a broad lumen lined by hyperplastic squamous epithelium. (B, C) The tumor cells possess a central circular nucleus with one or (hardly ever) 2 huge nucleoli. The cytoplasm consists of small to huge vacuoles. (D) Adipophilin can be indicated in intracytoplasmic lipid vacuoles in sebaceous cells. Hematoxylin and (A-C) eosin; immunohistochemistry of adipophilin (D) (all size pub = 100 m). Although any neoplasm in accessories genital glands is fairly rare in animals, spontaneous preputial gland adenoma is usually a relatively frequent tumor among neoplasms of the accessory genital glands in the Fischer 344 rat [3,4,5]. Preputial gland adenoma in male Fischer 344 rats may occur as a result of aging . Injection of 1 1,2-dimethylhydrazine has been shown to induce adenoma/carcinoma in preputial or clitoral glands (female counterpart of preputial glands) of CBA and BALB/c mice . Tumor incidence in wild mammals is usually reportedly very low. In nutria, moreover, only a few cases have been reported, involving adenocarcinoma in the lungs and uterus, as well as subcutaneous fibroma . Here, we have described preputial gland adenoma in a wild nutria. Footnotes Funding: This work was supported by a grant (NRF-2015R1C1A1A01055527) funded by the National Research Foundation of Korea. Conflict of Interest: The authors declare no conflicts of interest. Contributed by Author Contributions: Conceptualization: Hong IH, Yeon SC. Data curation: Hong IH, Kong JY, Yeon SC. Formal analysis: Hong IH, Kong JY, Kim HS. Funding acquisition: Hong IH. Investigation: Hong IH, Kong JY, Kim HS. Methodology: Kong JY, Kim HS. Supervision: Hong IH. Validation: Park JK, Jeong KS. Writing – original draft: Hong IH. Composing – examine & editing: Hong IH, Recreation area JK, Jeong KS..