When to worry about an armpit lump with lymphoma

Lymphoma can affect lymph nodes under the arm. A lump may reflect an active node, treatment-related change, infection, or another non-cancer cause. Size, texture, tenderness, skin changes, and whether it is changing over time help clinicians decide what to do next. Do not try to diagnose the lump by touch alone.

Note when you first noticed it, whether it is growing, and any fever, night sweating, itching, tiredness, or unexplained weight change. Avoid repeatedly pressing the area, which can make it sore. Contact your oncology team for advice about an examination and whether imaging or other tests are appropriate, especially if the lump appeared between planned visits.

Seek urgent medical help if the lump is accompanied by trouble breathing, swelling of the face or arm, severe pain, a high fever, confusion, marked weakness, or bleeding. Contact your oncology team promptly for a lump that is rapidly changing, firm and fixed, increasingly painful, or associated with worsening general symptoms.

Could this lump be related to lymphoma, an infection, or treatment? What changes should I monitor? Do I need an examination, scan, or blood test? Which symptoms should make me call the oncology service immediately?