Diabetes Insipidus: An Unusual Presentation of Adenocarcinoma of the Lung in a Patient with no Identifiable Lung Mass

CONTEXT: Lung cancers are known to metastasize to unusual sites. Despite this knowledge often times the diagnosis of a primary lung cancer gets delayed especially when the patient presents without respiratory symptoms. CASE REPORT: The patient discussed in our review is a 47-year-old female, smoker who had presented to several hospitals with months of headache, nausea and intermittent episodes of vomiting. She was noted to have hypernatremia due to diabetes insipidus and a pituitary lesion on her magnetic resonance images. The pituitary mass on biopsy was found to represent a metastatic focus from a primary lung adenocarcinoma. CONCLUSION: Clinicians should be aware of malignancies that are well known to metastasize to the posterior pituitary. Conversely, since not every patient presents with symptoms of metastasis, there is a need to recognize the clinical syndromes (e. g., diabetes insipidus-like symptoms or more subtle symptoms like cranial nerve palsies) associated with potential metastasis to the pituitary.