Abstract
Background: Merkel cell carcinoma (MCC) is an aggressive neuroendocrine cutaneous malignancy with an atypical presentation, associated with the merkel cell polyomavirus (MCPyV) in 80% to 90% of cases. The vowel mnemonic, AEIOU is representative of components of both risk factors and tumor characteristics: asymptomatic, expanding rapidly, immune compromised, older than age 50, and ultraviolet light exposure. The incidence has quadrupled over the past 20 years, particularly in immunocompromised individuals. Metastatic MCC has a median survival rate of 9.6 months. Early detection is critical, as the 5-year survival rate increases to nearly 80% with prompt treatment. The major implication for oncology advanced practitioners is to recognize risk factors in those currently under their care, especially those who are immunocompromised from chemotherapy and/or radiation. Risk factors include age older than 50, immunocompromised, and ultraviolet light exposure/fair skin. If the patient is older than 50, they now have the two risk factors that are seen with the highest percentage in patients presenting with a primary merkel cell tumor. Skin rashes or lesions are often associated with oncologic treatments and the recognition of risk factors and tumor characteristics of MCC may lead to earlier detection. There is an estimated 15.7-fold increased risk of MCC following chronic lymphocytic leukemia (CLL) diagnosis and 17-fold increased risk of CLL following MCC diagnosis. MCC should be in the differential for a reaction following treatment for CLL. Pathology is required to determine if a lesion is an aggressive malignancy vs. a reaction to chemotherapy. Biopsy is critical in patients who exhibit AEIOU risk factors presenting with a suspicious lesion reported as painless with red, dome shaped, and rapidly growing. Patients with a confirmed diagnosis of merkel cell carcinoma should be referred to a multidisciplinary team for clinical decision making and coordination of care. Treatment options for merkel cell carcinoma include wide surgical excision, adjuvant radiation, immunotherapy, and chemotherapy for metastatic disease.
