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© 2002 American Society for Clinical Oncology
Unusual Presentations of Lung CancerCase 1. Diabetes Insipidus as the Initial Manifestation of Non-Small-Cell Lung CancerUniversity of Michigan, Ann Arbor, MI A 57-year-old man presented with polyuria of 4 weeks’ duration. He had no other complaints, and his physical examination was unremarkable. His 24-hour urine volume was 8,500 mL, with a serum osmolality of 328 mOsm/kg and a serum arginine vasopressin level of less than 1 pg/mL. Findings were consistent with central diabetes insipidus. He was treated with daily deamino-8-D-arginine vasopressin (desmopressin acetate; DDAVP), and showed marked improvement in his polyuria. A magnetic resonance imaging scan of his head revealed multiple brain lesions consistent with metastases, including one in the pituitary infundibulum (Fig 1). A computed tomography scan of his chest showed innumerable tiny nodules throughout the left lung with increased interstitial markings and mediastinal lymphadenopathy (Fig 2). A bone scan revealed multiple metastatic lesions. On bronchoscopy examination, there were no endobronchial lesions, but bronchoalveolar lavage revealed non–small-cell carcinoma (Fig 3). His DDAVP requirement decreased significantly after whole-brain radiotherapy. He then received two cycles of carboplatin and paclitaxel followed by two cycles of carboplatin and gemcitabine, both of which induced profound fatigue with relative stability of disease. He opted to discontinue chemotherapy and has no evidence of progression 3 months after his last chemotherapy treatment.
Pituitary gland metastases occur in 1% to 5% of patients with advanced cancer at autopsy, with lung and breast cancer accounting for 65% to 75% of cases.1 More than half of pituitary metastases primarily involve the posterior lobe, 10% to 20% primarily affect the anterior lobe, and only 1% to 2% involve the infundibulum.2 Most pituitary metastases are found incidentally or at autopsy and are asympto-matic.1,3,4 Among patients with clinically evident pituitary metastases, up to 70% develop diabetes insipidus (DI), while recent series suggest that half of patients exhibit signs of anterior hypopituitarism.5-7 Other common symptoms include headache, visual changes, and cranial nerve palsy.5,6,8 Nearly all patients with pituitary involvement have multiple CNS metastases and widespread metastatic disease.2,3,9 DI as the initial manifestation of malignancy is rare.3,7,10,11 Computed tomography scans fail to demonstrate a pituitary abnormality in many patients with pituitary metastases documented by subsequent magnetic resonance imaging scans.12 Among patients with advanced cancer, a pituitary mass is twice as likely to be a metastatic focus as an adenoma.13 Pituitary metastases can be differentiated from adenomas by the rapid onset or progression of symptoms, patient age more than 50 years, presence of DI or cranial nerve palsy, history of malignancy, and unsuccessful treatment with bromocriptine. The clinical hallmarks of central DI are excessive thirst, large volumes of hypotonic urine, low serum levels of antidiuretic hormone (ADH), and correction of symptoms by exogenous ADH. Among patients with DI, 10% to 20% will be found to have pituitary metastases.3 There have also been several reports of DI caused by hypothalamic metastases.9,14 The relative rarity of clinically evident DI in cancer patients may be due to the need for near-total destruction of the posterior lobe or disruption of more than half of the supraoptic-hypothalamic tract fibers to significantly suppress ADH secretion, or a lack of enthusiasm for pursuing the diagnosis in very ill patients with advanced disease.3 Although the administration of DDAVP usually improves the symptoms of DI, most patients require replacement therapy for life because of the irreversible, destructive nature of the pituitary lesion. However, a few reports have noted the resolution of DI after radiotherapy to the brain.9,12,14 Despite the overall poor prognosis associated with pituitary metastases, early treatment with radiotherapy or surgical decompression may improve both the quality and quantity of life in symptomatic patients.6
NOTES Copyright © 2002 American Society of Clinical Oncology REFERENCES 1. Chiang M-F, Brock M, Patt S: Pituitary metastases. Neurochirurgia 33: 127-131, 1990[Medline] 2. Teears RJ, Silverman EM: Clinicopathologic review of 88 cases of carcinoma metastatic to the pituitary gland. Cancer 36: 216-220, 1975[CrossRef][Medline] 3. Kimmel DW, O’Neill BP: Systemic cancer presenting as diabetes insipidus. Cancer 52: 2355-2358, 1983[CrossRef][Medline] 4. Nelson PB, Robinson AG, Martinez AJ: Metastatic tumors of the pituitary gland. Neurosurgery 21: 941-944, 1987[Medline] 5. Aaberg TM Jr, Kay M, Sternau L: Metastatic tumors to the pituitary. Am J Ophthalmol 119: 779-785, 1995[Medline] 6. Morita A, Meyer FB, Laws ER: Symptomatic pituitary metastases. J Neurosurg 89: 69-73, 1998[Medline] 7. Sioutos P, Yen V, Arbit E: Pituitary gland metastases. Ann Surg Oncol 3: 94-99, 1996[Abstract] 8. Branch CL, Laws ER: Metastatic tumors of the sella turcica masquerading as primary pituitary tumors. J Clin Endocrinol Metabol 65: 469-474, 1987[Abstract] 9. Yap H-Y, Tashima CK, Blumenschein GR, et al: Diabetes insipidus and breast cancer. Arch Intern Med 139: 1009-1011, 1979[Abstract] 10. Krol TC, Wood WS: Bronchogenic carcinoma and diabetes insipidus. Cancer 49: 596-599, 1982[CrossRef][Medline]
11. Fragetta F, Galia A, Grasso G, et al: Pulmonary adenocarcinoma metastatic to pituitary craniopharyngioma. J Clin Pathol 53: 946-947, 2000 12. Matsuda R, Chiba E, Kawana I, et al: Central diabetes insipidus caused by pituitary metastasis of lung cancer. Intern Med 34: 913-918, 1995[Medline]
13. ten Bokkel Huinink D, Veltman GAM, Huizinga TWJ, et al: Diabetes insipidus in metastatic cancer. Ann Oncol 11: 891-895, 2000 14. Noseda A, Louis O, Mockel J, et al: Diabetes insipidus from metastatic oat cell carcinoma: Recovery after brain irradiation. Am J Med Sci 289: 27-30, 1985[Medline]
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Copyright © 2002 by the American Society of Clinical Oncology, Online ISSN: 1527-7755. Print ISSN: 0732-183X
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