Swollen glands are a common clinical complaint. "Glands" are actually lymph nodes, which are present throughout the body. In the head and neck, there is a rich supply of lymphatics and lymph nodes, what are part of the immune system.
When lymph nodes become enlarged they can be painful or painless. Painful enlargement is a sign of infection or inflammation, while painless enlargement can be a sign of multiple processes. Examples include cancer, low grade infections, granulomatous diseases.
Lymph node enlargement for greater than 4 weeks should be assessed by a medical specialist. Often that specialist is an otolaryngologist, although primary care physicians are well trained to assess swollen glands.
Then picture on the left is of a patient with massive neck swelling on the right side (left side of the screen), and the diagnosis was made by performing an open neck biopsy. This was a lymphoma (a type of cancer affecting the lymph nodes).