# Chiari I Malformation With Concomitant Nonfunctioning Pituitary and Adrenal Tumors

## TL;DR

This paper reports the first case of a patient with Chiari I malformation and nonfunctioning pituitary and adrenal tumors, suggesting a possible new underlying mechanism.

## Contribution

The first reported case of Chiari I malformation with nonfunctioning pituitary and adrenal tumors is presented.

## Key findings

- A 45-year-old female was diagnosed with Chiari I malformation and nonfunctioning pituitary and adrenal incidentalomas.
- The patient had normal IGF-1 levels, suggesting a different mechanism for the co-occurrence of these conditions.
- Posterior fossa decompression was performed without complications, and pituitary adenectomy was not pursued.

## Abstract

Chiari 1 malformation (CM1) is a rare finding that has been described with growth hormone (GH)-secreting pituitary adenomas and with an endothelial PAS domain protein 1 gain-of-function mutation syndrome. We describe the first reported case of a patient diagnosed with CM1 and nonfunctioning pituitary and adrenal incidentalomas. Our case describes a 45-year-old female who was found to have cerebellar tonsillar ectopia consistent with CM1, a pituitary tumor, and bilateral adrenal incidentalomas. She was diagnosed after presenting with 2 weeks of upper extremity weakness and paresthesia. A comprehensive endocrine workup including insulin like growth factor (IGF-1) was normal. She underwent posterior fossa decompression without complication. Pituitary adenectomy was not pursued as there was no evidence of compression of the chiasm or the surrounding structures. In previous case reports it has been proposed that GH-secreting adenomas contribute to CM1 by causing hypertrophy of soft tissue structures in the skull base, overcrowding the posterior fossa. Given that our patient had normal IGF-1 levels, there could be a different underlying mechanism that contributed to the concomitant occurrence of CM1 with the pituitary and adrenal tumors.