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MRI Findings of Immune Checkpoint Inhibitor-Induced Hypophysitis: Possible Association with Fibrosis
R Kurokawa1, Y Ota2, W Gonoi3
1From the Department of Radiology (R.K., W.G., E.M., S.A., Y.U., O.A.), Graduate School of Medicine, The University of Tokyo, Tokyo, Japan.
AJNR. American Journal of Neuroradiology
|August 9, 2020
Summary
Immune checkpoint inhibitor-induced hypophysitis often leads to permanent hypopituitarism. Characteristic MR imaging findings include geographic hypoenhancing lesions in the anterior pituitary, aiding diagnosis.
Area of Science:
- Radiology
- Endocrinology
- Oncology
Background:
- Hypophysitis is a known adverse effect of immune checkpoint inhibitors (ICIs).
- ICI-induced hypophysitis frequently results in irreversible hypopituitarism, necessitating long-term hormone replacement therapy.
- Established MR imaging features for ICI-induced hypophysitis are lacking, despite its clinical significance.
Purpose of the Study:
- To review and identify characteristic MR imaging features of immune checkpoint inhibitor-induced hypophysitis.
- To establish a diagnostic imaging profile for this condition.
Main Methods:
- Retrospective international multicenter study involving 20 melanoma patients treated with ICIs.
- Radiologists evaluated pituitary gland and stalk enlargement, enhancement patterns, and lesion characteristics on MR imaging.
- Clinical symptoms and hormone levels were correlated with imaging findings.
Main Results:
- Pituitary and stalk enlargement observed in 12/20 and 20/20 patients, respectively.
- Nineteen patients exhibited geographic hypoenhancing lesions in the anterior pituitary lobe, often with T2WI hypointensity.
- High rates of persistent thyrotropin and corticotropin deficiencies were noted.
Conclusions:
- Geographic hypoenhancing lesions in the anterior pituitary are characteristic and frequent MR imaging findings of ICI-induced hypophysitis.
- These lesions likely represent fibrosis and are valuable for differentiating ICI-induced hypophysitis from other pituitary pathologies.
- Identifying these MR imaging features aids in the diagnosis and management of ICI-induced hypophysitis.
