The collarbone (clavicle) is a long bone extending horizontally across the upper chest, connecting the sternum (breastbone) to the shoulder blade. Because of its superficial position, any underlying changes or growths are easily visible and felt as a lump or bump. A mass in this area is common, but the cause varies widely, ranging from simple, harmless growths to indications of a more serious medical condition. Understanding the potential origins of a clavicular lump—whether from trauma, soft tissue, or systemic processes—is the first step toward proper evaluation. This review provides general information about the different types of masses that can occur near the collarbone.
Lumps Caused by Injury and Structural Changes
Lumps arising from the bone or adjacent joints often result from mechanical stress or trauma. One of the most frequent causes of a hard, fixed lump on the clavicle itself is a healed fracture. When the clavicle breaks, the body produces a temporary scaffolding of bone material called a callus to bridge the gap.
The fracture callus is composed of new bone and cartilage tissue, forming a natural part of the healing process. Because the clavicle lies just beneath the skin, this bony lump is frequently palpable and visible even after the fracture has fully united. While the callus typically remodels over time, a permanent, noticeable hard lump often remains, especially if the bone fragments healed with overlap or angulation.
A different structural lump occurs at the outer end of the clavicle, forming the acromioclavicular (AC) joint where it meets the shoulder blade. An AC joint separation, often called a shoulder separation, results from an injury that tears the ligaments holding the joint together. When the stabilizing ligaments are disrupted, the weight of the arm pulls the shoulder blade down, causing the clavicle to ride upward and form a distinct, prominent bump above the joint line.
This visible deformity is the displaced end of the clavicle and signifies the severity of the ligament damage. Osteoarthritis, a wear-and-tear condition, breaks down joint cartilage over time. The body may respond to this degeneration by producing small, bony projections called osteophytes, or bone spurs, which can cause the joint to appear enlarged and form a firm lump near the shoulder.
Common Benign Soft Tissue Masses
Many lumps near the collarbone originate in the soft tissues just beneath the skin, and most of these are benign. Lipomas are one of the most common soft tissue masses, often found in the clavicular region. These growths are composed entirely of mature fat cells and form a soft, doughy mass that is usually painless.
Lipomas are characterized by mobility; applying light pressure causes the mass to easily slide under the skin. They tend to grow very slowly over months or years, and their consistency helps distinguish them from firmer, bony, or fluid-filled growths. Lipomas typically do not require removal unless they are cosmetically bothersome or are pressing on a nerve, causing discomfort.
Another common soft tissue mass is the sebaceous cyst (epidermoid or keratin cyst). These masses form when a hair follicle or oil gland duct becomes blocked, leading to a sac-like structure filled with keratin, the protein found in skin, hair, and nails. Unlike the soft lipoma, a sebaceous cyst usually feels firm or rubbery to the touch and is generally less mobile, remaining relatively fixed beneath the skin.
Sebaceous cysts may sometimes display a small, dark opening (punctum) on the skin surface, indicating the clogged pore. These cysts are typically harmless but can become inflamed, tender, or infected if the sac ruptures or bacteria enter the opening. Less commonly, other benign fibrous growths, such as fibromas, can also present as firm, non-tender lumps in the superficial tissues.
Lumps Caused by Inflammation and Lymph Node Swelling
A lump in the supraclavicular area (just above the collarbone) is frequently due to enlarged lymph nodes, which are small, bean-shaped immune system filters. Swollen lymph nodes (lymphadenopathy) indicate the body is fighting an infection or reacting to inflammation. In this area, temporary swelling is commonly associated with infections in the head, neck, or upper chest, such as a severe cold, strep throat, or an ear infection.
These infection-related nodes are typically soft, slightly tender, and mobile, and they should reduce in size as the underlying illness resolves, usually within a few weeks. However, the supraclavicular nodes drain lymph fluid from distant, deep-seated areas of the body. The left supraclavicular node, sometimes called Virchow’s node, receives drainage from the abdominal and pelvic cavities via the thoracic duct.
Persistent or increasing swelling in a supraclavicular lymph node, especially if the mass feels hard, fixed, and non-tender, raises concerns for a systemic issue or the spread of cancer. Malignancies in the chest (like lung or esophageal cancer) or in the abdomen (like stomach or ovarian cancer) can metastasize to these nodes. The location is an important clue, as right-sided swelling is more commonly linked to the chest, while left-sided swelling may signal pathology originating below the diaphragm.
Beyond lymph nodes, localized infection can form an abscess, which is a collection of pus. An abscess presents as a hot, red, tender, and intensely painful lump that develops rapidly. This type of lump requires medical intervention to drain the accumulated fluid and treat the bacterial infection.
Warning Signs and Necessary Diagnostic Steps
While many collarbone lumps are benign, certain characteristics prompt immediate medical evaluation. Warning signs include rapid growth (over weeks or months), or a lump that feels unusually hard and immobile, suggesting it is fixed to underlying structures. The presence of systemic symptoms alongside the lump is also concerning, including unexplained weight loss, night sweats, or a persistent fever.
Any lump accompanied by changes in the overlying skin, such as ulceration, redness, or color change, needs professional assessment. Furthermore, a lump that is newly painful, or one that persists for more than four to six weeks without a clear cause, should not be ignored. These signs suggest a need to rule out more serious conditions, including malignancy or chronic infection.
The diagnostic process begins with a thorough physical examination, where a healthcare provider assesses the lump’s size, mobility, consistency, and tenderness. This initial assessment guides the next steps, which usually involve medical imaging. A simple X-ray can detect bony abnormalities like fractures or bone spurs, while an ultrasound can differentiate between solid masses, fluid-filled cysts, and enlarged lymph nodes.
More advanced imaging, such as a Computed Tomography (CT) scan or Magnetic Resonance Imaging (MRI), may be ordered to visualize the mass and its relationship to surrounding structures. The definitive diagnostic step is often a biopsy, which involves taking a tissue sample, either through fine-needle aspiration or surgical excision. Analyzing the cells under a microscope provides an accurate diagnosis, confirming whether the lump is a benign growth, an inflammatory process, or a cancerous tumor.