A rare clinical case of concomitant bullous hemorrhagic pyoderma gangrenosum and follicular thyroid cancer is reported. The etiologic and pathogenetic issues of pyoderma gangrenosum are briefly described, and its association with myelodysplastic disorders, inflammatory bowel diseases, and oncopathology is emphasized. The modern classification and the major and minor diagnostic criteria are provided. Attention is drawn to the need for a comprehensive, thorough examination of patients with gangrenous pyoderma to exclude visceral pathology.