Welcome to the Rare Classroom, a new series from Patient Worthy. Rare Classroom is designed for the curious reader who wants to get informed on some of the rarest, most mysterious diseases and conditions. There are thousands of rare diseases out there, but only a very small number of them have viable treatments and regularly make the news. This series is an opportunity to learn the basics about some of the diseases that almost no one hears much about or that we otherwise haven’t been able to report on very often.

Eyes front and ears open. Class is now in session.

The disease that we will be learning about today is:

Adenoid Cystic Carcinoma

Sometimes called adenocyst or malignant cylindroma.

What is Adenoid Cystic Carcinoma?

• Adenoid cystic carcinoma is a form of rare cancer. It can appear in many different areas of the body
  • However, it most often originates in the salivary glans. It is the third most common malignant tumor of the salivary gland
  • Other places that it can appear include the breast, trachea, brain, and lung, among others
• In general adenoid cystic carcinoma is a well-differentiated tumor and grows slowly in most cases. Therefore, patients can survive for years even after the tumor has spread
  • The tumors have a distinct histological pattern of cords or ‘nests’ of epithelial cells that surround and glandular structures of the impacted organ
• The cancer has a tendency to recur at the site of origin a long time after initial treatment and remission
• It can also spread to relatively distant sites within the body
• About 1,200 people are diagnosed annually in the US

How Do You Get It?

• A key genomic event in the origin of adenoid cystic carcinoma is activation of the gene MYB, an oncogenic transcription factor gene. This usually takes place as a result of a gene fusion, usually with NFIB 
• This alteration is found in the fast majority of cases
• Most cases take place in adults between age 40-60, but can be found in people of all ages
• Mutations of the NOTCH1 gene are also associated with this cancer
  • Patients that test positive for this gene often have a worse prognosis

What Are The Symptoms?

• Symptoms can vary depending on where the cancer tumor appears. When adenoid cystic carcinoma appears in the salivary glands, the most common site, symptoms may include:
  • Numbness of the face or lower lip
  • Weakness of the facial muscles
  • Nerve pain
• If the lacrimal gland (tear ducts) are affected, these symptoms may appear:
  • Changing vision
  • Bulging eyes
• Skin
  • Pain
  • Pus or blood discharge
  • Nodules or plaques appearing on the skin
• Lower respiratory tract
  • Difficulty breathing
  • Hoarseness
  • Coughing up blood
  • Lung inflammation
  • Malaise

How Is It Treated?

• The primary method of treatment for adenoid cystic carcinoma is surgical removal of the tumor. However, this approach can be challenging in the head and neck region and the pattern of growth can make it challenging to remove it all, with different “nests” of cancer cells being present without direct connection to the original tumor.
• Often, radiation therapy is administered following surgery
• For advanced cases, fast neutron therapy is often used.
• Chemotherapy may be used for metastatic disease, and is usually determined on a case by case basis.
  • However, in general, adenoid cystic carcinoma is resistant to chemotherapy.
• Five year survival rate is 89 percent; however, the 15 year survival rate is 40 percent, indicating deaths from metastatic disease occurring later on

Where Can I Learn More???

• Check out our cornerstone on this disease here.
• Learn more about this condition from the Oral Cancer Foundation.