Concurrent mammary adenocarcinoma and lymphoma in MNU-induced tumorigenesis in a Sprague-Dawley female rat (case report)

A.F. GAL, V. MICLĂUȘ, M. TAULESCU, P. BOLFĂ, F. TĂBĂRAN, Cosmina BOUARI, C. CĂTOI

Abstract


N-Methyl-N-nitrosourea (MNU) induces a high incidence of mammary adenocarcinomas inSprague-Dawley rats. Our paper describes associated mammary adenocarcinoma and malign lymphoma inmammary parenchyma in a Sprague-Dawley female rat inoculated with MNU. After a quarantine period,20 rats were selected at random divided into 2 groups (1st and 2nd groups) and housed accordingly. 37 dayold female Sprague-Dawley rats from the 1st group received a single dose of 55mg MNU/kg body weight.At 9.5 months after MNU administration the experiment was ended. Necropsy and histopathologicalexaminations were carried out on each rat. The samples harvested for the histopathological examinationswere fixed in 10% buffered formalin solution and then processed by paraffin technique. Sections werestained by Masson’s trichrome and hematoxylin-eosin staining techniques. Mammary tumor inductionfollowing MNU-inoculation in the 1st group was high (90% of all tumors). In the 1st group were identifiednon-mammary tumors too representing about 10% of all tumors. In one individual of the 1st group werediagnosed multiple in situ mammary ductal carcinomas in several mammary glands (tumor size variedfrom 0.8/0.5cm to 7.9/6.5 cm). Following histological examination of all mammary tumors, a diffuseinfiltrate (with lymphoblasts) extended throughout the tumor mass. The poorly differentiated lymphoblastsrevealed an invasive character often bordering the tubular cancerous mammary structures. Frequentlytumoral lymphoblasts induced severe compression atrophy on mammary tumor tubular structures. Basedon presented histological features an unusual case with both mammary cancer and lymphoma wasdescribed in a female Sprague-Dawley rat following MNU-inoculation.

Keywords


mammary adenocarcinoma, lymphoma, mammary gland, N-Methyl-N-nitrosourea, rat.

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DOI: http://dx.doi.org/10.15835/buasvmcn-vm:69:1-2:8414


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