The diagnosis of a lymphoma is always confirmed by the microscopic examination of a tissue sample.
A doctor may suspect a lymphoma due to a clinical investigation, or based on specific investigation results (blood tests, x-rays…). If a lymphoma is suspected, a tissue sample (biopsy) is required for microscopic examination. This investigation is essential to establish the lymphoma diagnosis.
If the diagnosis is confirmed, complementary investigations are required to establish a pre-therapeutic evaluation. It determines the extent of the disease and guides the choice of treatment plan.
The diagnosis of a lymphoma is based on a biopsy, a surgical intervention that extracts a sample of tissue.
The biopsy is a usually benign intervention, often under local anaesthetic if the tumour affects a superficial node (neck, armpits, groin), but it can be a heavier intervention is the node to be sampled is in the thorax or the abdomen.
The tissue sample is then analysed to validate or invalidate the lymphoma suspicion. To be precise, the analysis must include a study of the immunological characteristics (immunohistochemical investigation, which distinguishes between B and T-cell lymphomas) and genetic characteristics (karyotype and molecular biology) of the tumour cells.