Merkel cell carcinomas (cutaneous neuroendocrine carcinomas) are rare skin malignancies that demonstrate both neuroendocrine and epithelial differentiation. They are so named for their histological similarity to normal Merkel cells of the skin. They most frequently occur on the head and neck of the elderly but can also be seen elsewhere on the body. White individuals have 20 times the risk of blacks for developing Merkel cell carcinoma; it is, therefore, thought that UV radiation may play a role in the pathogenesis.
Affected individuals will typically present with an asymptomatic solitary nodule. Patients with metastatic disease may demonstrate weight loss, fatigue, and lymphadenopathy. Despite aggressive treatment, recurrence rates are high, metastases are common, and mortality is approximately 30-50% at 2 years.
Pink, bluish-red, or reddish-brown cutaneous to subcutaneous firm nodules. The overlying skin is usually intact and may be shiny with telangiectasias or even appear normal in color. Ulceration is rare. Size normally ranges from 0.5-5.0 cm, and most are solitary.
Of Merkcel cell carcinomas, 50% arise in the head and neck region; the remainder occur in the extremities, buttocks, and trunk.
Regional lymphadenopathy is a sign of more advanced disease.
- Chest radiography may be helpful in ruling out metastases from oat cell lung cancer
- Staging CT or MRI may aid in planning treatment