Pyoderma gangrenosum is a rare, painful, noninfectious, ulcerative, reactive neutrophilic skin condition. It is characterized by ulcers that can spread quickly showing undermined violaceous borders. Since there is no single diagnostic test, early diagnosis is always challenging. The aggressive nature of classical pyoderma gangrenosum may become apparent only with time. Pulmonary involvement of pyoderma gangrenosum maybe underreported. We describe a case of classical pyoderma gangrenosum in a 65-year-old man with pulmonary involvement, who presented with a painful fluctuate nodule and ulcer with mucopurulent and hemorrhagic exudates, and with a monoclonal gammopathy, IgA type. One month later the ulcer and hemoptysis all disappeared after treatment with glucocorticosteroids. The pulmonary manifestations of pyoderma gangrenosum were also reviewed.