Merkel cell carcinoma (MCC) is a rare, aggressive skin malignancy that has a propensity for local recurrence and metastasis to the lymph nodes. In this case report, we discuss a 54-year-old female with rheumatoid arthritis (RA) who had received treatment with prednisone (15 mg/day) for symptom relief and management. The patient visited our hospital with complaints of a nodule in right preauricular area. Computed tomography (CT) scans revealed no distant metastasis. The patient underwent surgical resection and histopathological evaluation of the nodule led to the diagnosis of MCC. The patients received post-surgical treatment with 6 MeV electronic wire radiotherapy. Six months later, CT of the head, neck, abdomen and chest demonstrated a right cervical lymph node mass at the C2 level. The patient then underwent cervical lymph node biopsy and pathological diagnosis confirmed metastatic MCC. One month after the lymph node biopsy, the patients received postoperative intensity modulated radiation therapy in the biopsied area. The patient did not experience any adverse effects to the therapy. In conclusion, the MCC patients with RA can tolerate radiation therapy. As MCC is a highly malignant neoplasia, considering the immune checkpoint inhibitors can lead to immune-related adverse events, detection of MCC at earlier stages is associated with better survival. The treatment decisions of MCC patients with RA continues is still challenging.