Endocrine Abstracts

Introduction: Metastases in pituitary gland are extremely rare with a reported prevalence of 1% among all pituitary tumor resections and 1 to 3.6% among post-mortem studies (1). Breast and lung cancer are the most common sites of primary tumor that have been reported to metastasize in pituitary gland and about 7% of all metastases are symptomatic (2.3).

Case report: A 62-year-old male with a 40-pack-year smoking history and no previous medical conditions presented with nausea, vomiting, fever, somnolence and a 6 kg weight loss in two weeks. Physical examination showed bradylalia, hypoacusis, drowsiness, tempo-spatial disorientation, fever (38 degrees Celsius) and an enlarged supraclavicular lymphatic nodule. No focal neurological deficits or meningeal irritation was found. Routine laboratory tests detected an elevated serum lipase (841 U/l), triglycerides (313 mg/dl), lactate dehydrogenase (994 U/l), creatinine (1.75 mg/dl), uric acid (10.69 mg/dl), c-reactive protein (10.9 mg/dl), fibrinogen (612 mg/dl), d-dimer test (1099 ng/ml), normal serum potassium and slightly elevated serum natrium (145.8 mmol/l). Additional, endocrinological work-up detected panhypopituitarism (FT4 = 4.8 pmol/l, TSH = 0.481 mIU/l, testosterone = 0.170 nmol/l, LH = 0.216 IU/l, cortisol = 47.9 nmol/l) and elevated prolactin levels (415.9 mUI/l). Proper substitutive hormone therapy was adopted. Hole body CT scan revealed the presence of a pituitary tumor, enlarged lymph nodes with necrotic areas in mediastinum and bilateral adrenal glands macroadenomas. Biopsy from supraclavicular lymphadenopathy, followed by pathological examination and immunohistochemistry uncovered a non-differentiated big cell neuroendocrine pulmonary carcinoma metastasis, staining positive for Thyroid Transcription factor 1, Synaptophysin, Chromogranin and Ki67 was positive in 90% of the tumoral cells. The patient condition deteriorated rapidly (obnubilation, tempo-spatial disorientation) with laboratory test showing elevated serum sodium and low potassium levels (Na = 159 mmol/l, K = 2.5 mmol/l). We suspected diabetes insipidus and antidiuretic hormone analogue therapy was started with a slightly improvement on patient condition and laboratory findings. Head MRI taken at three weeks after his initial admission revealed a pituitary tumor (31.4/30.6/27.5 mm) that exerted major compression on the third ventricle and determined internal hydrocephalus. The patient was relocated to neurosurgery department, where a ventriculoperitoneal shunt was placed. Unfortunately, the patient clinical condition continued to deteriorate despite correct treatment and after approximately five weeks after presentation, he passed away.

Conclusion: Panhypopituitarism and diabetes insipidus due to pituitary metastases represents a rare condition that highly complicates the diagnostic and management of patients with pulmonary carcinoma.