ALTERNATE NAMES

Carcinoma of Thymus; Malignant Thymoma; TET; THYC; Thymoma Type C; Thymoma, Malignant; Thymoma, Malignant (Morphologic Abnormality); Thymoma, Type C; Thymoma, Type C (Morphologic Abnormality); Thymus Carcinoma

DESCRIPTION

Thymic Carcinoma (TC) is a rare, aggressive form of cancer that starts on the thymus, a gland that is primarily responsible for the production and maturation of immune cells. The thymus consists of two types of cells: epithelial cells (the tissue that covers organs and other body parts) and lymphocytes (a type of white blood cell). TC is also called thymic epithelial tumor (TET) because it originates from abnormal epithelial cell growth.

There are three major types of TET:

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  Thymoma is the most common type. It is a slow growing tumor that rarely spreads beyond the thymus. This form is the least likely to reach listing level severity and is not considered a CAL-level condition.

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  TC is a more severe form of TET that develops fast and is more likely to spread to other parts of the body. It also generally requires more complex treatment. It is considered a CAL-level condition because it is likely to spread beyond the regional lymph nodes.

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  Small Cell Cancer of the Thymus is one of the rarest cancers that occurs in humans. Small Cell Cancer of the Thymus is not the same disorder as TC. It is currently a CAL condition.

Although extremely rare, TC can occur in children. It is more likely to occur in adults between ages 40 and 75 who have Asian or Pacific Islander heritage. It is more common in women.

DIAGNOSTIC TESTING, PHYSICAL FINDINGS, AND ICD-9-CM/ICD-10-CM CODING

Diagnostic testing: TC is diagnosed by:

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  Physical examination;

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  Results of imaging studies (i.e., chest x-ray, MRI, CT scan, PET scan) showing evidence of metastases or recurrence; and

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  Biopsy.

Physical findings: Most individuals with TC have no symptoms in the early stages of the disease. Symptoms often arise when a tumor impacts the chest organs. These symptoms may include:

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  Chest pain or pressure;

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  Persistent cough;

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  Shortness of breath;

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  Hoarseness;

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  Swelling in the neck or face; and

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  Trouble swallowing.

TC tumors can cause damage to the phrenic nerve, which controls the diaphragm’s movement, resulting in phrenic nerve palsy which may lead to weakness of the diaphragm or diaphragmatic paralysis, affecting breathing.

Tumors may also compress the vena cava (large veins that carry blood to the heart) causing a very serious condition known as superior vena cava syndrome. Symptoms of superior vena cava syndrome may include:

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  Chest pain;

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  Hoarseness;

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  Cough;

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  Shortness of breath;

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  Fatigue;

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  Dizziness;

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  Headaches;

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  Swelling in the neck, face, arms, hands and upper chest; and

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  Enlarged and bulging veins in the neck and check.

ICD-9: 164.0

ICD-10: C37; E32.8

PROGRESSION

TC typically spreads to nearby tissues such as the lining of the chest cavity, eventually metastasizing to distant organs, often through lymph nodes. Prognosis is poor due to the high frequency of recurrences and metastases in the pleura, lung, lymph nodes, bone, brain, and liver. The survival rate at 5 years is 35%.

TREATMENT

Treatment of TC includes total thymectomy (removal of the thymus) and complete tumor excision usually accompanied by neoadjuvant or adjuvant therapy consisting of radiotherapy, chemotherapy, or both. In case of metastases, platinum-based chemotherapy is the first-line treatment.

Suggested MER for Evaluation:

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  Clinical history and examination that describes the diagnostic features of the impairment;

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  Results of imaging studies (i.e., chest x-ray, MRI, CT scan, PET scan) showing evidence of metastases or recurrence; and

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  Biopsy results.

Suggested Listings for Evaluation:

Meets

13.15 B

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