MERKEL CELL CARCINOMA
Merkel Cell Cancer; Trabecular Cancer; Apudoma of Skin; Small Cell Neuroepithelial Tumor of Skin; Primary Small Cell Carcinoma of Skin; Toker Tumor; Primary Cutaneous Neuroendocrine Tumor; Malignant Trichodiscoma; Neuroendocrine Carcinoma of the Skin
Merkel Cell Carcinoma (MCC) is a rare, aggressive skin cancer that forms in the outer layer of the skin (epidermis). MCC often appears in areas of the skin exposed to the sun, such as the head and neck, arms, legs, and trunk. However, MCC may also develop anywhere on the body, even on areas not exposed to sunlight. Merkel Cell Carcinoma with Metastases occurs when the tumor spreads to other parts of the body. MCC that has metastasized has a significantly higher mortality than malignant melanoma of the skin.
The incidence of MCC is somewhat greater for males. It is most common in people older than age 50, although it can occur at any age.
DIAGNOSTIC TESTING, PHYSICAL FINDINGS, AND ICD-9-CM CODING
Diagnostic testing: Diagnosis is made with a sentinel lymph node biopsy and immunohistochemical stains. Blood tests, such as liver function tests, may be used to detect the spread of MCC to internal organs. MCC is difficult to diagnose through imaging studies in its early stages.
Physical findings: The first sign of MCC is usually a fast-growing, painless nodule (tumor) on the skin. The shiny nodule may be skin colored or may appear in shades of red, blue or purple that initially may be mistaken as a benign cyst. Most MCCs appear on the face, head or neck, but they can develop anywhere on the body, even on areas not exposed to sunlight.
Physical exam may reveal the following findings: a new skin lesion, an enlarged lymph node, and enlarged liver. The lesion may be a small spot on the arm. It may be firm, painless, and shiny. These lumps or tumors can be red, pink, or blue in color and vary in size from less than a quarter of an inch to more than two inches.
ICD-9: 209.31 – 209.36
ONSET AND PROGRESSION
MCC metastasizes quickly and spreads to other parts of the body, tending towards the regional lymph nodes. The tumor tends to invade underlying subcutaneous fat, fascia, and muscle. MCC has an extremely poor prognosis after it has spread to distant sites, especially the organs (such as, liver, lung, bone, or brain). For people with positive lymph nodes, median survival is 13 months compared to 40 months in those people with negative nodes.
Treatment for MCC is based on the stage and location of the lesion, and whether the tumor has spread to the lymph nodes or other parts of the body. Treatment may consist of: 1) surgical excision of the primary lesion, 2) lymph node surgery, 3) radiation therapy, and 4) chemotherapy. Chemotherapy is usually reserved for late stage MCC, and mostly as a palliative therapy.
SUGGESTED PROGRAMMATIC ASSESSMENT*
Suggested MER for evaluation: The adjudicator needs medical evidence from treating sources and hospitals. A biopsy confirms the diagnosis of MCC.
Suggested Listings for Evaluation:
MCC with metastases to or beyond the regional lymph nodes meets the listing.
MCC that has invaded deep extradermal structures (for example, skeletal muscle, cartilage, or bone) medically equals the listing.