Diabetes insipidus as a main symptom of cancer

Hormonal disturbances are a possible complication of malignant disease not derived primarily from the endocrine cells. They may result from paraneoplastic hormonal activity of the tumor, such as frequently described Cushing's syndrome in the course of ectopic secretion of adre-nocorticotropic hormone (ACTH), a syndrome of inappropriate secretion of antidiuretic hormone (SIADH) and malignancy related hypercalcemia. Endocrinopathy may also be due to the destruction of the organ of internal secretion by the local invasion or distant tumor metastasis, such as secondary lesions in the hypothalamic-pituitary area. Thus, the clinical picture of malignancy sometimes may be dominated by the symptoms of hormonal deficiency. Diabetes insipidus (DI) is a rare complication of neoplastic disease, and its presence requires extended diagnostics. We present two case reports of patients with metastases to the pituitary gland (MP) without an incriminating history suggesting malignancy, where DI was only the tip of the iceberg called cancer. Careful clinical evaluation and additional studies allowed the diagnosis of advanced ma-lignancy. A 74-year-old man with a 3-month history of polydipsia (up to 5 l/day), polyuria, nycturia and loss of appetite (without cachectic appearance) was admitted to our department with DI suspicion. Additionally he suffered from essential hypertension well controlled with amlodipine. He has been a regular smoker for 10 years. The history of malignancy and symptoms of hormonal imbalance except posterior lobe were negative. Physical examination revealed no significant abnormalities; blood pressure and heart rate were 110/70 mm Hg and 80 per minute respectively. Plain chest X-ray revealed a tumor of the right pulmonary hilus. The chest computed tomography (CT) showed a pathological mass sized 31 mm × 29 mm in one segment of the right lung with a pathological enlargement of the mediastinal lymph nodes: right paratracheal, subcarinal and aor-topulmonary region (Figure 1). Bronchofiberoscopy did not detect any tumor. For appropriate evaluation of lymphadenopathy and to obtain material for pathomorphologic diagnosis we decided to perform mediastinoscopy. The pathologically changed lymph node (group 4 according to American Thoracic Society Definitions of Regional Nodal Stations) was excised. The histopatholog-ical assessment of the lymph node revealed metastasis of squamous carcinoma. Magnetic resonance imaging (MRI) of the head with post-gadolinium enhancing identified two pathological lesions of the sellar area. One dumbbell-shaped mass was located in the intrasellar and su