Swollen (enlarged) lymph nodes: when need to visit Medical oncologist or Hematologist? ✔️Swollen lymph nodes usually occur as a result of infection from bacteria or viruses. ✔️Rarely, swollen lymph nodes are caused by cancer. There are two the most common areas to find swollen lymph nodes, 1️⃣ neck and 2️⃣ axillary areas (armpits). ℹ️ When lymph nodes swell, a patient might notice: ✔️tenderness and pain in the lymph nodes, ✔️ swelling (may be the size of a pea or kidney bean,