Spontaneous Gastric Carcinoid Tumors in the Striped Field Mouse (Apodemus agrarius).

Abstract

ABSTRACT. Gastric carcinoid tumors were found in seven of 135 striped field mice (Apodemus agrarius) by routine histopathologic examination. All these carcinoids occurred in mature striped field mice aged 72-100 weeks. Six animals were females and only one was male. Only two of seven tumors were detectable by gross examination. Grossly, tumors were located in the fundus of the glandular stomach. All seven tumors were microscopically single in the stomach and two mice exhibited extragastric metastasis. Tumors from all the mice were characterized by densely packed sheets of round to polygonal cells, subdivided into packets by a fine fibrovascular stroma. The cytoplasm of all tumor cells from all the mice contained argyrophil granules when stained by Grimelius and Sevier-Munger silver procedures. All seven mice with gatric carcinoids exhibited positive immunoreactivity to neuron specific enolase. Psammoma bodies, concentrically laminated microcalcification, were characteristic findings in gastric carcinoids from five mice. There were also a concomitant and independent hepatocellular adenoma in one case and hepatocellular carcinoma in two cases. The present cases provide the first description of spontaneous gastric carcinoid tumors in the striped field mice. -KEY WORDS: gastric carcinoid tumor, striped field mouse.

Gastric Neuroendocrine Tumors With Parietal Cell Atrophy in a Long-term Carcinogenicity Study in Rats

“…Striped field mice ( Apodemus agrarius ) are reported to exhibit a relatively high incidence of gastric NE tumors, with an incidence of 5% among aged mice. 1 Mastomys ( Praomys natalensis ) are reported to be particularly prone to the development of spontaneous gastric NE tumors, with an incidence of 40% to 60% observed between the ages of 12 to 24 months. 2 However, despite the rare spontaneous occurrence of these tumors in most rodent species, gastric NE tumors have been induced in common laboratory rats and mice following long-term treatment with various agents that block gastric acid secretion for prolonged periods.…”

Histopathological and Immunohistochemical Characterization of Methyl Eugenol–induced Nonneoplastic and Neoplastic Neuroendocrine Cell Lesions in Glandular Stomach of Rats

“…In NTP 2-year rodent bioassays, the most common spontaneous and chemically induced gastric neoplasms in rats and mice are squamous cell papilloma and squamous cell carcinoma of the nonglandular stomach (Chandra, Nolan, and Malarkey 2010). Spontaneous tumors of glandular stomach (adenomas, adenocarcinomas, benign, and malignant NE cell tumors) are extremely rare in laboratory rodents in NTP 2-year bioassays (Chandra, Nolan, and Malarkey 2010); however, spontaneous gastric NE tumors are described in cotton rats, Sprague-Dawley rats, striped field mouse, and Mastomys natalenesis mice (Majka and Sher 1989; Snell and Stewart 1969; Oh, Chae, and Jang 1997; Cui et al 2000). Among chemically induced glandular stomach neoplasms in rodent bioassays, NE tumors are the most common (Chandra, Nolan, and Malarkey 2010).…”

Gastric Neuroendocrine Tumors in a 2-Year Oncogenicity Study With CD-1 Mice

“…With regard to the occurrence of neuroendocrine tumors in rodents, Praomys (Mastomys) natalensis is known as the rodent with a high genetic susceptibility for the development of carcinoid tumors due to hypergastrinemia and is used as an experimental model in this respect (15,16,24). Few spontaneous gastric carcinoid tumors were found in striped eld mice (Apodemus agrarius) (26), and eight cases were reported in NTP studies (19).…”