A 21-year-old female was admitted to Tamono City Hospital with chief complaint of dyspnea due to spontaneous pneumothorax. The patient was transferred to our clinic for further examination of abnormal chest X-ray findings together with skin lesions and other symptoms of polyuria, amenorrhea and narrowed visual fields. Histochemical and electron microscopic examination of lung tissue obtained by open lung biopsy led to the diagnosis of eosinophilic granuloma. Furthermore, enhanced computed tomography and magnetic resonance images showed the existence of an intracranial tumor in the supra-hypophyseal region which was interpreted as the cause of hormonal and visual disturbances. Because of dyspnea and enlargement of intracranial tumor, treatment with steroid hormone was commerced followed by tapering of the dose. Chest X-ray findings and skin lesions improved markedly and the intracranial tumor regressed significantly with this steroid therapy, indicating that the intracranial tumor represented involvement with eosinophilic granuloma.