Pathology dictionary

Malignant neoplasm

What is a malignant neoplasm?

Malignant neoplasm is a medical term used to describe a cancerous type of tumour. It is a descriptive term that includes many different types of cancerous tumours. Malignant neoplasms can start anywhere in the body and the specific type of tumour depends on the kind of cells found inside the tumour. Types of malignant neoplasms include carcinomas, sarcomas, melanoma, and lymphomas. The opposite of a malignant neoplasm is a benign neoplasm. Unlike a benign neoplasm, the cells in a malignant neoplasm are able to spread or metastasize to other parts of the body.

Malignant neoplasm is considered a preliminary diagnosis because it does not say anything about the types of cells in the tumour. Pathologists often use this term when they do not have enough information about the tumour to make a more specific or final diagnosis. This may happen after only a small sample of the tumour is removed in a procedure called a biopsy. Additional tests such as immunohistochemistry, fluorescence in situ hybridization (FISH), in situ hybridization, and next-generation sequencing may be performed to help better characterize the tumour. A more specific or final diagnosis can often be reached after the entire tumour is removed and examined under the microscope.

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