Primary harderian gland neoplasms in mice

Area of Science:

• Oncology
• Experimental Pathology
• Mouse Models

Background:

• Harderian glands are accessory orbital glands in rodents.
• Neoplasms of the harderian gland can occur spontaneously in experimental mice.
• Understanding spontaneous tumor development is crucial for carcinogenicity studies.

Purpose of the Study:

• To characterize the incidence, types, and progression of spontaneous harderian gland neoplasms in mice.
• To identify specific mouse strains and age groups with higher tumor susceptibility.
• To analyze the histological subtypes of adenomas and their relationship to adenocarcinomas.

Main Methods:

• Observation of 574 spontaneous harderian gland neoplasms in 12,157 untreated mice.
• Analysis of tumor incidence across different sexes, ages, 6 inbred strains, and 3 hybrid stocks.
• Histological classification of adenomas into papillary, cystic papillary, acinar, and cystic types.
• Assessment of adenocarcinoma evolution from adenomas and metastatic potential.

Main Results:

• Tumor incidence was higher in females (458 adenomas, 27 adenocarcinomas) than males (86 adenomas, 3 adenocarcinomas).
• The highest tumor incidence was observed in mice older than 24 months.
• BALB/c mice exhibited the highest incidence, accounting for 463 of all neoplasms.
• Papillary adenomas were most frequent; cystic papillary type was associated with gross lesions.
• Most adenocarcinomas appeared to arise from adenomas, with 5 cases showing metastasis or invasion.

Conclusions:

• Age and strain significantly influence spontaneous harderian gland neoplasm development in mice.
• Histological subtypes of adenomas vary in incidence and association with lesions.
• Adenocarcinomas frequently evolve from adenomas, with a low rate of metastasis observed.