Cerebral metastasis of Merkel cell carcinoma following resection with negative margins and adjuvant external beam radiation: a case report

Abstract

Background Merkel cell carcinoma (MCC) is a rare and aggressive neuroendocrine tumor of the skin. It is associated with advanced age, ultraviolet (UV) radiation, and Merkel cell polyomavirus. It has a predilection for the lymphatic system, but rarely spreads to the central nervous system. Case presentation A 71-year-old Caucasian man with a history of rheumatoid arthritis and MCC of the right lower eyelid and cheek presented with left-sided hemineglect and word-finding difficulty. Twenty months earlier he had undergone local excision of a 3 cm lesion with negative margins, negative sentinel lymph node biopsy, and external beam radiation. On presentation he was found to have a 6.3 cm mass in the right frontotemporal region. He underwent prompt resection, with pathological analysis consistent with metastatic MCC. He subsequently underwent stereotactic radiosurgery (SRS) and adjunctive immunotherapy with pembrolizumab. He has since tolerated the therapy well and is currently without neurological symptoms or evidence of recurrence. Conclusions Cerebral metastasis of MCC is a rare event and should be considered when a patient with a history of MCC presents with neurological symptoms. Optimal treatment regimens of these rare cases are unclear; however, prompt resection, stereotactic radiosurgery, and adjunctive immunotherapy have shown an initial positive response in this patient.

Merkel cell carcinoma brain metastasis with radiological findings mimicking primary CNS lymphoma: illustrative case

“… 2 , 10 Risk factors for MCC include older age and light-skinned individuals with extensive sunlight exposure and immunosuppression. 10 , 14 Cases of patients with human immunodeficiency virus infection, 17 chronic lymphoid leukemia, 18 and RA 19 developing MCC intracranial metastasis have been reported. Grubb et al 19 reported a case of a 71-year-old White man with a history of RA receiving hydroxychloroquine and MCC of the head and neck that was surgically excised with negative margins, negative sentinel lymph node biopsy, and radiation to the tumor bed who presented with neurological symptoms resulting from MCC brain metastasis 20 months after initial treatment.…”

“…10 , 14 Cases of patients with human immunodeficiency virus infection, 17 chronic lymphoid leukemia, 18 and RA 19 developing MCC intracranial metastasis have been reported. Grubb et al 19 reported a case of a 71-year-old White man with a history of RA receiving hydroxychloroquine and MCC of the head and neck that was surgically excised with negative margins, negative sentinel lymph node biopsy, and radiation to the tumor bed who presented with neurological symptoms resulting from MCC brain metastasis 20 months after initial treatment. Similarly, in this case presentation, the patient developed distant metastasis 24 months after initial diagnosis even after surgical excision of the primary tumor with negative margins, negative sentinel lymph node biopsy, and radiation to the tumor bed.…”

“…Few cases of MCC brain metastasis treated with immunotherapy have been reported. In 2021, Grubb et al 19 reported the use of adjunct immunotherapy pembrolizumab and SRS after resection of a right MCC brain metastasis. At 6-months follow-up, patient is stable from his disease.…”