Adenoid cystic carcinoma (ACC) is a rare cancer originating in the body’s glandular tissues. It is often found in the head and neck region, particularly in the salivary glands, but it can also develop in various other locations. ACC is known for its slow growth, but it can be locally aggressive and spread to distant parts of the body.
What is Adenoid Cystic Carcinoma?
Adenoid cystic carcinoma is a malignant tumor arising from cells that produce substances like mucus or saliva. It is characterized by specific microscopic patterns, distinguishing it from other cancers. Common patterns include cribriform, where tumor cells form structures with small, round spaces, often described as having a “Swiss cheese” appearance, and tubular and solid formations. The solid pattern is generally associated with a more aggressive disease course.
While ACC typically progresses slowly, it can show aggressive local growth, invading surrounding tissues. A notable feature is its tendency to spread along nerves, known as perineural invasion, which can make complete tumor removal challenging. Though it rarely spreads to nearby lymph nodes, distant metastasis, often to the lungs, liver, or bones, is a concern, sometimes occurring years after initial treatment.
Common Locations and Symptoms
ACC can develop in various secretory glands throughout the body, with the head and neck region being the most frequent site. It commonly affects major and minor salivary glands, such as the parotid, submandibular, and sublingual glands. Initial symptoms in these areas may include a painless lump in the mouth, face, or neck. As the tumor grows, it can cause facial numbness, muscle weakness, or difficulty swallowing.
Beyond salivary glands, ACC can arise in lacrimal glands, potentially causing a bulging eye or vision changes. In the trachea (windpipe) or larynx (voice box), symptoms may include hoarseness, speech changes, or difficulty breathing. Less common sites include the breast, skin, cervix, or prostate gland, with symptoms varying by location. A slow-growing lump might be felt in the breast, or skin lesions could present with pain.
How ACC is Diagnosed
Diagnosing adenoid cystic carcinoma relies primarily on obtaining tissue for microscopic examination. If ACC is suspected, a healthcare provider will typically perform a biopsy, which involves removing a small piece of the suspicious tissue. This tissue sample is then sent to a pathologist, who examines the cells under a microscope to confirm ACC and identify its specific characteristics.
Imaging techniques support diagnosis and are crucial for staging the cancer. Computed tomography (CT) scans, magnetic resonance imaging (MRI), and positron emission tomography (PET) scans are commonly used to determine the tumor’s exact size and extent within the body. While imaging provides important information about the tumor’s location and spread, definitive diagnosis is always confirmed through pathological analysis of a biopsy specimen.
Treatment Approaches for ACC
The primary approach for treating adenoid cystic carcinoma is surgical removal of the tumor. Surgeons aim to remove the entire cancerous tissue with a margin of healthy tissue around it to help ensure all cancer cells are eliminated. The extent of surgery depends on the tumor’s location and size, sometimes involving removal of nearby structures if cancer has invaded them.
Following surgery, radiation therapy is often recommended to reduce the risk of the cancer returning. Radiation uses high-energy beams to destroy any remaining cancer cells. It can also be used as a standalone treatment if surgery is not feasible due to the tumor’s location. While chemotherapy and targeted therapies are less effective compared to surgery and radiation, they may be considered for advanced or metastatic ACC, particularly when the cancer has spread to distant sites. These systemic treatments aim to control the disease throughout the body.