Skip to main content
ENDO 2026 Main banner

Thyroid Biology and Disease

MON-342 - Immune Checkpoint Inhibitor-Induced Painful Thyroiditis

Monday, June 15, 2026
9:00 AM - 2:00 PM CT
Location: ENDOExpo; Poster Floor

    Abstract Poster Presenter(s)

  • KP

    Keyla Payano, MD

    Resident
    ICAHN SCHOOL OF MEDICINE AT MOUNT SINAI
    New York, NY, United States

    • Senior Author/Primary Investigator(s)

  • IB

    Ilana Ramer Bass, MD/MPH

    Assistant Physician
    Mount Sinai
    New York, New York, United States

    • Co-Author(s)

  • LA

    Lisa A. Abraham, MD

    Icahn School of Medicine at Mount Sinai
    New York, United States



Background:
Immune checkpoint inhibitor (ICI)–induced thyroiditis occurs in approximately 5–20% of treated patients (1). The thyrotoxic phase is typically mild and painless, presenting with symptoms such as heat intolerance, palpitations, or tremor, and often transitions to hypothyroidism. In contrast, painful thyroiditis associated with ICIs has been rarely reported.

Clinical

Case:
A 36-year-old woman with a history of right-sided breast cancer status post bilateral mastectomy and adrenal insufficiency secondary to pembrolizumab presented with six days of tachycardia, diarrhea, palpitations, and shortness of breath. Two days prior to admission, she developed anterior neck pain without noticeable thyroid enlargement. Laboratory evaluation revealed a suppressed TSH of 0.01 mIU/L (0.4–4.2), elevated free T4 of 2.5 ng/dL (0.8–1.5), total T4 of 24 µg/dL (5–12.2), and an erythrocyte sedimentation rate of 101 mm/hr (0–38). Graves disease was excluded by negative thyrotropin receptor antibodies. She was initially treated with propranolol and acetaminophen for symptom control. Due to persistent pain, prednisone was initiated, followed by an outpatient taper, with complete resolution of symptoms.

Conclusion:
This case highlights a rare but important presentation of ICI-induced thyroiditis manifesting as painful thyrotoxicosis. Prompt recognition of atypical features and early initiation of anti-inflammatory therapy can lead to rapid symptom resolution and improved patient outcomes.

References:
Drug Effects on the Thyroid. B. Burch Henry. New England Journal of Medicine 2019 Vol. 381 Issue 8 Pages 749-761. DOI: 10.1056/NEJMra1901214https://doi.org/10.1056/NEJMra1901214

*Unless otherwise noted, all abstracts presented at ENDO must not be released to the press or the public until the date and time of presentation. For oral presentations, the abstracts are embargoed until the session begins. The Endocrine Society reserves the right to lift the embargo on specific abstracts that are selected for promotion prior to or during ENDO.*