Lymphoma is a cancer originating in lymphocytes, the infection-fighting white blood cells of the immune system. These cells primarily reside within the lymphatic system, a network of vessels, tissues, and organs including the lymph nodes, spleen, and bone marrow. When lymphoma develops, it leads to the uncontrolled growth of these cells, often causing lymph nodes to swell. While most shoulder pain is typically caused by common musculoskeletal issues like tendonitis or arthritis, pain in this area can sometimes signal a deeper, systemic disease. This article explores the specific, though uncommon, mechanisms by which lymphoma can present as shoulder pain.
The Link Between Lymphoma and Shoulder Pain
Yes, lymphoma can cause shoulder pain, but this is an unusual presentation of the disease. When shoulder pain is the primary symptom, it is typically rare and often secondary to the cancer’s physical progression rather than an initial complaint. Since the vast majority of shoulder pain cases are due to mechanical injuries, a systemic cause like cancer is often overlooked.
Both Hodgkin lymphoma and Non-Hodgkin Lymphoma (NHL) can cause pain depending on where the malignant cells accumulate. Non-Hodgkin Lymphoma, particularly Diffuse Large B-Cell Lymphoma (DLBCL), is a common type of lymphoma to involve the musculoskeletal system and present as a shoulder neoplasm. The pain usually arises from the physical presence of the tumor mass interfering with surrounding structures.
How Lymphoma Causes Localized Pain
Shoulder pain caused by lymphoma occurs through several distinct physical mechanisms involving structures around the joint.
Mass Effect and Nerve Compression
The most common mechanism is the “mass effect,” where enlarged lymph nodes or tumor masses press on nearby nerves and tissues. Lymph nodes in the axilla (armpit) and supraclavicular area (above the collarbone) can become significantly swollen. When these nodes grow, they can compress the brachial plexus, a network of nerves originating in the neck that controls movement and sensation in the shoulder and arm. This compression causes radiating pain, numbness, or weakness, often resulting in a deep, persistent ache that does not respond to typical physical therapy or anti-inflammatory medications.
Bone Infiltration
Lymphoma can directly infiltrate the bone structure of the shoulder, specifically the humerus (upper arm bone) or scapula (shoulder blade). This is known as osseous lymphoma. The presence of lymphoma cells within the bone can lead to osteolytic lesions, where the cancer actively destroys bone tissue. This structural damage causes intense, deep-seated pain that may worsen with movement or persist even at rest.
Referred Pain (Kehr’s Sign)
In rare cases, shoulder pain can be “referred” pain originating from an enlarged organ in the abdomen. If lymphoma causes significant enlargement of the spleen (splenomegaly), the organ can press against the diaphragm. Irritation of the diaphragm causes pain signals that the brain misinterprets as originating from the left shoulder tip, a phenomenon known as Kehr’s sign.
Systemic Symptoms That Accompany Lymphoma
Shoulder pain is rarely the sole sign of lymphoma, as the disease is systemic and often presents with body-wide symptoms. These constitutional symptoms, often referred to as “B symptoms,” suggest a more active or advanced disease state.
The three classic B symptoms are:
- Drenching night sweats, severe enough to soak through clothing and bedding.
- Unexplained weight loss, defined as losing 10% or more of body weight over six months without dieting.
- A persistent or recurring fever, typically 100.4°F (38°C) or higher, not caused by an infection.
The presence of these B symptoms alongside localized pain is a significant indicator of a systemic issue. Additionally, many individuals experience persistent fatigue that does not improve with rest. The most common physical sign of lymphoma is the painless swelling of lymph nodes, called lymphadenopathy, usually felt as a firm, rubbery lump in the neck, armpit, or groin. This persistent swelling, especially when accompanied by B symptoms, helps differentiate cancer-related shoulder pain from a simple musculoskeletal injury.
When to Discuss Shoulder Pain with a Doctor
While isolated shoulder pain is rarely a sign of cancer, specific characteristics warrant investigation for systemic causes. Pain that is insidious, intermittent, and progressively worsening, especially if it is not relieved by rest, physical therapy, or standard medications, should be discussed with a healthcare provider. Pain that is noticeably worse at night and interferes with sleep also prompts further investigation.
Any shoulder pain accompanied by unexplained weight loss, drenching night sweats, or persistent fever demands prompt medical attention. The diagnostic process begins with a physical examination to check for swollen lymph nodes and assess shoulder range of motion. Blood tests, such as a complete blood count and lactate dehydrogenase (LDH) levels, may be ordered to look for abnormal cell counts.
If a systemic cause is suspected, the doctor will order advanced imaging like X-rays, Computed Tomography (CT) scans, or Magnetic Resonance Imaging (MRI) to visualize the bones and soft tissues. The definitive diagnosis for lymphoma requires a biopsy of the abnormal lymph node or bone lesion to confirm the presence of malignant cells.