Neuroimaging of hypophysitis: etiologies and imaging mimics

Abstract

Hypophysitis is an inflammatory disease affecting the pituitary gland. Hypophysitis can be classified into multiple types depending on the mechanisms (primary or secondary), histology (lymphocytic, granulomatous, xanthomatous, plasmacytic/IgG4 related, necrotizing, or mixed), and anatomy (adenohypophysitis, infundibulo-neurohypophysitis, or panhypophysitis). An appropriate diagnosis is vital for managing these potentially life-threatening conditions. However, physiological morphological alterations, remnants, and neoplastic and non-neoplastic lesions may masquerade as hypophysitis, both clinically and radiologically. Neuroimaging, as well as imaging findings of other sites of the body, plays a pivotal role in diagnosis. In this article, we will review the types of hypophysitis and summarize clinical and imaging features of both hypophysitis and its mimickers.

Ectopic pituitary neuroendocrine tumor arising in the sphenoid sinus with an avid 18F-fluorodeoxyglucose uptake masquerading as malignancy: A case report

“…PitNETs are benign tumors that grow from pituitary gland cells and can cause various hormonal abnormalities. PitNETs, formerly known as pituitary adenomas, are renamed in the fifth edition of the World Health Organization (WHO) classification 2021 [4 , 5] and 2022 World Health Organization Classification of Endocrine and Neuroendocrine Tumors [6 , 7] . The change in the nomenclature of this tumor was made based on the following clinical and pathological features of PitNETs inconsistent with “adenomas,” referring to benign epithelial tumors: PitNETs originate from neuroendocrine pituitary hormone-producing cells; some PitNETs can exhibit aggressive behaviors, such as infiltration into the surrounding structures, frequent recurrence after treatment, and occasional metastasis [8] .…”

Postpartum Hypophysitis: A Case Report and a Literature Review

“…Additionally, a rare type of primary hypophysitis predominantly affecting the female population is xanthomatous hypophysitis, histologically different from other subtypes (infiltration of foamy histiocytes) but clinically can be similar to LHy [ 3 ]. Gadolinium-enhanced magnetic resonance imaging (MRI) is very helpful and helps prevent invasive diagnosis with biopsy [ 4 ].…”