Peer-reviewed veterinary case report
Mammary tumors in pet rats - what to know
By Vergneau-Grosset, Claire et al.·Published in Journal of the American Veterinary Medical Association·2016·View original on PubMed →
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Original publication title: Description of the prevalence, histologic characteristics, concomitant abnormalities, and outcomes of mammary gland tumors in companion rats (Rattus norvegicus): 100 cases (1990-2015).
- Species:
- rodent
Plain-English summary
This study looked at mammary gland tumors in pet rats, specifically examining 100 cases from 1990 to 2015. The most common type of tumor found was a fibroadenoma, which is a benign growth, while a smaller number were malignant tumors called carcinomas. Many of the rats with these tumors also had other health issues, such as pituitary gland tumors and reproductive tract problems. It was noted that if a rat had a fibroadenoma removed without further treatment, it could develop another one within a few months. Overall, the findings suggest that if your rat has a lump, it’s important to have it checked thoroughly by a vet.
Abstract
OBJECTIVE To describe the prevalence, histologic characteristics, concomitant abnormalities, and outcomes for various types of mammary gland tumors in companion rats (Rattus norvegicus). DESIGN Retrospective case series. ANIMALS 100 client-owned rats. PROCEDURES Medical records of companion rats that had an SC mass and were examined at a veterinary teaching hospital between 1990 and 2015 were reviewed. Information regarding the signalment, age at mass detection, reproductive sterilization status, histologic diagnosis of the SC mass, location of the initial and all subsequent SC masses, treatments administered, and clinical outcomes was extracted from each record and summarized. RESULTS 105 SC masses were initially detected in 100 rats. The most prevalent SC mass identified was mammary gland fibroadenoma (56/105 [53%]), followed by mammary gland carcinoma (13/105 [12%]). Overall, 26 of 105 (25%) masses were malignant. Sexually intact males were more likely to have nonmammary SC tumors than sexually intact females. In rats receiving no adjunctive treatment after excision of a mammary gland fibroadenoma (n = 16), a second fibroadenoma was detected 1 to 8 months after initial excision, at a median of 4.5 months after surgery. A concomitant pituitary gland tumor was identified in most rats with mammary gland fibroadenoma (21/28 [75%]) and other types of mammary gland tumors (10/17 [59%]). Fourteen of 35 (40%) rats with mammary gland fibroadenoma had concomitant reproductive tract abnormalities. CONCLUSION AND CLINICAL RELEVANCE Results suggested that, like other species, companion rats with SC masses should undergo a thorough diagnostic workup that includes histologic examination of the excised mass.
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Search related cases →Original publication on PubMed: https://pubmed.ncbi.nlm.nih.gov/27823365/