Skin & Soft Tissue: Merkel Cell Carcinoma (MCC) Merkel Cell Carcinoma (MCC) BasicsVery Aggressive Neuroendocrine Tumor with Early SpreadAppearance: Frim & Red with UlcerationMostly AsymptomaticStain Positive for CK-20 & TFF-1 (Thyroid Transcription Factor)AssociationsImmunosuppression (HIV, Multiple Myeloma, Chronic Lymphocytic Leukemia, etc.)ElderlyPolyomavirusSun ExposureTreatmentPrimary Treatment: Wide Local Excision (WLE), SLNB & XRTPreop: Need PET & MRI/CTMargins: 1-2 cmPositive LN: Node Dissection and/or XRTDistant Metastases: Consider Systemic Therapy, XRT or Surgery Merkel Cell Carcinoma 1 Merkel Cell Carcinoma 2 Merkel Cell Carcinoma 3 References Paoli J. Wikimedia Commons. (License: CC BY-SA-4.0)Peter KD. Wikimedia Commons. (License: CC BY-3.0)Doc 103. Wikimedia Commons. (License: CC BY-SA-3.0)