[A case of small cell lung cancer complicated by Cushing syndrome]

When a 45-year-old man visited his local hospital with a complaint of chest discomfort and coughing, an abnormal chest X-ray shadow was found. On referral to our department, pigmentation was mainly observed on his face, however, no striae cutis distensae or facial swelling was observed. After a systemic examination, Stage IV small cell lung cancer with Cushing's syndrome was diagnosed. Marked increases in ACTH levels were observed, but no abnormality was found in the pituitary MRI findings, and therefore ACTH-producing small cell lung cancer was suspected. Chemotherapy was administered in addition to appropriate treatment for Cushing's syndrome. The tumor temporarily began to decrease in size, but hypercortisolemia remained, and thus adrenal hormone synthesis-inhibiting therapy was concurrently administered. Subsequently, cortisole began to decrease, but it could not be sufficiently controlled, resulting in occasional colonization by bacteria. Hypercortisolemia is believed to induce the suppression of the immune system, thereby affecting the outcome and QOL more than the immediate symptoms of cancer. Therefore, from an early stage, it is believed that adrenal cortical hormone synthesis-inhibiting therapy should be performed concurrently with chemotherapy, if hypercortisolemia cannot be controlled by radiation and chemotherapy alone.