Spontaneous regression in an ulcerated CK7 positive Merkel cell carcinoma

Area of Science:

• Oncology
• Dermatology
• Immunology

Background:

• Merkel cell carcinoma (MCC) is a rare, aggressive skin cancer, typically affecting older individuals and linked to UV exposure and immunosuppression.
• MCC is less common in individuals with darker skin tones.
• The case involves a 40-year-old woman with no typical risk factors presenting with unusual skin lesions.

Observation:

• A 40-year-old woman presented with multiple, slow-growing, ulcerated skin plaques on her knee.
• Histopathology revealed diffuse dermal infiltration by small round cells positive for CK20, CK7, neuron-specific enolase, and chromogranin, consistent with MCC.

Findings:

• The patient's skin lesions showed complete spontaneous regression within one month post-skin biopsy.
• No recurrence of the Merkel cell carcinoma was observed during a two-year follow-up period.

Implications:

• The findings suggest that diagnostic skin biopsy may trigger an immune response capable of inducing MCC regression.
• This case underscores the potential role of the immune system in managing Merkel cell carcinoma, even in non-elderly patients.