Adenoid cystic carcinoma (ACC)
Adenoid cystic carcinoma (ACC) is a rare malignant cancer primarily affecting secretory glands, most commonly found in the major and minor salivary glands of the head and neck, but it can also appear in other areas such as the trachea, tongue, and breast. This type of carcinoma is more prevalent in women than men, particularly in individuals over the age of fifty. While the exact risk factors remain unclear, ACC is typically diagnosed in adults between their fourth and sixth decades of life.
The symptoms of ACC can vary based on the tumor's location, with common manifestations including slow-growing, painless masses, and potential nerve paralysis in larger tumors. Diagnosis is primarily achieved through histologic examination of biopsy samples, as there are currently no effective serum markers for screening. Treatment usually involves surgical intervention, sometimes supplemented by radiotherapy, although chemotherapy options are limited for metastatic cases.
The prognosis for ACC can be challenging; while the disease generally progresses slowly, it may lead to serious complications if it metastasizes, predominantly to the lungs and liver. Studies indicate a five-year disease-specific survival rate of approximately 89%, though this declines significantly over a longer period. Understanding ACC is crucial for timely diagnosis and appropriate management for affected individuals.
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Subject Terms
Adenoid cystic carcinoma (ACC)
ALSO KNOWN AS: Adenocystic carcinoma, cribriform carcinoma, cylindroma, malignant cylindroma, AdCC
RELATED CONDITIONS: Adenoma, adenocarcinoma
DEFINITION: Adenoid cystic carcinoma (ACC) is a rare malignant cancer of the secretory glands. Neoplasms usually originate in the major and minor salivary glands of the head and neck region but can also occur in places such as in the trachea, tongue, lacrimal glands, breast, skin, and vulva.
Risk factors: Though environmental and genetic risk factors have not been identified, studies show that ACC is more common in people over fifty and is more common in women than men.
Etiology and the disease process: There is little information available regarding pathogenesis except for some evidence suggesting that the TP53 tumor-suppressor gene is inactivated in the most aggressive forms or stages of ACC.
Incidence: Both children and adults may develop ACC. However, most patients are diagnosed between the fourth and sixth decades of life. ACC affects more women than men at a ratio of approximately 3:2.
Symptoms: Signs and symptoms depend on the origin of the neoplasm. ACC may be characterized by slow-growing, painless masses of the mouth or face. Larger tumors may cause pain or nerve paralysis if the neoplasm invades the peripheral nerves. Lacrimal gland tumors may cause proptosis (forward displacement of the eyeball) or changes in vision.
Screening and diagnosis: Unfortunately, no screening tests exist because of a lack of serum markers. Diagnosis is made after histologic analysis obtained through biopsy or resection of a tumor. ACC is classified into three major groups according to distinctive histologic growth patterns: cribriform, tubular, and solid.
Treatment and therapy: The primary treatment option for adenoid cystic carcinoma is surgery. Postoperative radiotherapy or neutron beam therapy is sometimes recommended to help limit local failure. There is no effective chemotherapy for metastatic or unresectable ACC. However, several clinical trials are testing the effectiveness of chemotherapeutic drugs (for example, paclitaxel and gemcitabine) when used alone or in combination with other drugs. Radiofrequency ablation and cryoablation are also being explored as treatment options.
Prognosis, prevention, and outcomes: ACC growth and disease progression tend to be slow but relentless. ACC is atypical of carcinomas and seldom metastasizes to regional lymph nodes. is the predominant reason for treatment failure and occurs most frequently in the lung, followed by the liver. Tumors with solid growth patterns and perineural invasion of major nerves or positive margins tend to have poor prognosis. According to the Oral Cancer Foundation, one study followed 160 ACC patients and found that disease-specific survival was 89 percent at five years and 40 percent at fifteen years.
Bibliography
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"What Is ACC?" Adenoid Cystic Carcinoma Organization International. Adenoid Cystic Carcinoma Org. Intl., n.d. Web. 26 Aug. 2014.