A False Pituitary Tumor

Abstract

A false pituitary tumor describes pituitary enlargement due to intracranial hypotension. Reported previously primarily in the neurological literature, we present this case referred to endocrinology for evaluation of a pituitary mass. A 24-year-old male was referred to endocrinology for evaluation of pituitary enlargement without a hypo-enhancing lesion on magnetic resonance imaging (MRI). The main symptom reported was headache that was worse in the standing position and in the afternoon. He had no symptoms or signs of pituitary mass-effect, or hormone excess or deficiencies. Past medical history was relevant for a history of nerve schwannoma status post resection with subsequent spinal fusion. Biochemical evaluation of pituitary hormones was normal. Upon review of his pituitary MRI, other abnormalities seen were suggestive of intracranial hypotension. Based on his history and imaging findings, he was diagnosed with intracranial hypotension causing a "false pituitary tumor" rather than pituitary enlargement or abnormality. Further evaluation revealed multiple spinal leaks that were patched. His symptoms subsided within a few days of repair. Endocrinologists should be aware of the possible misdiagnosis of a pituitary mass due to intracranial hypotension.

Keywords: CSF leak; intracranial hypotension; pituitary tumor.

Figure 1.

Coronal (A) and sagittal (B) views of the pituitary gland in a brain MRI. The pituitary is mildly enlarged with rounded convexity of the superior margin (white arrows).

Figure 2.

MRI imaging of the pituitary gland (white arrows) before (left) and 6 months after (right) a spinal blood patching in a patient with CSF leak (imaging corresponding to another patient with CSF leak resulting in enlargement of the pituitary gland; case and images courtesy of Dr. John L.D. Atkinson).