Abstract
A 55-year-old man visited a dermatologic clinic with a complaint of erythema with pain on both lower legs. The eruptions were not successfully treated with antibiotics. The patient was therefore referred to our hospital and was diagnosed with erythema nodosum based on the clinical features, blood biochemical findings, and results of histological examination. Treatment with oral prednisolone was started and the eruption disappeared promptly. A whole body examination was performed to investigate the background of the skin lesions. Colon cancer was found by colon fiberscopy. Lymph node swelling in the cervical and porta hepatic regions was also found by positron emission tomography, and a diagnosis of lymph node tuberculosis was made on the basis of the results of a cervical lymph node biopsy.
