Concomitant manifestation of pyoderma gangrenosum and colorectal carcinoma

Pyoderma gangrenosum is an ulcerative skin disease of unknown origin and is commonly associated with inflammatory bowel disease, arthritis or lymphoproliferative disorders. Only sporadic cases of pyoderma gangrenosum in combination with malignant disease of the gastrointestinal tract have been reported until now. We report on a 53-year-old patient who suffered injury to the right scapula while gardening. Initially, the patient had only a superficial wound of the upper skin but in the subsequent weeks the lesion developed into an ulcerative defect and pyoderma gangrenosum was diagnosed. Laboratory test results, ultrasound of the abdomen and computed tomography of the chest and abdomen were normal. Immunosuppressive therapy with prednisolone and azathioprine was initiated. Four months later the patient was admitted to the gastroenterology department for further examination because of chronic fatigue, subfebrile temperature and a positive fecal occult blood test. Colonoscopy showed a semicircular carcinoma of the sigmoid colon measuring 3-4 cm. A left-sided hemicolectomy was performed. Microscopic examination revealed an adenocarcinoma (T3, N2, G3) and consequently the patient was given adjuvant chemotherapy. Nine months later the patient was asymptomatic and the pyoderma gangrenosum had recovered. Pyoderma gangrenosum is not only associated with inflammatory bowel disease or lymphoproliferative disorders. This case report demonstrates that colorectal carcinoma must also be considered as a possible differential diagnosis. The fast and complete remission of pyoderma gangrenosum following surgical treatment of colorectal carcinoma emphasizes a causal relationship.