Where can a rat have a tumor? - briefly
Rats develop neoplasms in many organ systems, notably the mammary glands, liver, lungs, brain, skin, gastrointestinal tract, endocrine glands, and lymphoid tissue. Tumor occurrence is not limited to a single site and can appear in any of these locations.
Where can a rat have a tumor? - in detail
Rats develop neoplasms in a wide range of tissues. The most frequently reported sites include:
- Mammary glands, especially in females of advanced age.
- Skin and subcutaneous tissue, where fibrosarcomas and squamous cell carcinomas arise.
- Liver, with hepatocellular carcinoma and cholangiocarcinoma as common forms.
- Lungs, where bronchioloalveolar carcinoma and metastatic lesions are observed.
- Spleen, often presenting as lymphoma or histiocytic sarcoma.
- Brain, primarily gliomas and meningiomas.
- Bone, including osteosarcoma and chondrosarcoma.
- Gastrointestinal tract, especially the stomach and intestines, where adenocarcinomas occur.
- Reproductive organs, such as the uterus and testes, which can develop leiomyosarcoma or seminoma.
- Lymph nodes, frequently involved in disseminated lymphoma.
Spontaneous tumors tend to appear in older animals, while chemically induced or genetically engineered models produce lesions in targeted organs. Clinical signs vary with location: respiratory distress for pulmonary masses, abdominal enlargement for hepatic or gastrointestinal tumors, neurological deficits for central nervous system involvement, and weight loss or palpable masses for peripheral sites. Diagnosis relies on physical examination, imaging (radiography, ultrasound, MRI), and histopathological confirmation. Treatment options differ by organ system and tumor grade, ranging from surgical excision to chemotherapy and radiation therapy.