Giant Cell Arteritis/Polymyalgia Rheumatica and Atypical Pulmonary Carcinoid Tumor: A Paraneoplastic Syndrome?

Area of Science:

• Rheumatology
• Oncology
• Neurology

Background:

• Giant cell arteritis (GCA) is a common large-vessel vasculitis in older adults, typically affecting extracranial arteries.
• Central nervous system involvement, such as ischemic stroke, is rare in GCA.
• Paraneoplastic GCA associated with solid tumors is exceptional and poorly understood.

Purpose of the Study:

• To report a rare case of GCA potentially driven by a paraneoplastic mechanism.
• To highlight the association between GCA and solid tumors.
• To emphasize the importance of considering underlying malignancy in atypical GCA cases.

Main Methods:

• Case report of a 59-year-old man with GCA symptoms and neurological deficits.
• Diagnostic workup included imaging (Doppler ultrasound, PET-CT), inflammatory markers, and exclusion of atherosclerosis.
• Treatment involved corticosteroids and methotrexate, with monitoring of GCA and oncologic response.

Main Results:

• The patient presented with GCA symptoms, thalamic ischemia, and vertebral artery stenosis, despite a negative temporal artery biopsy.
• A mediastinal mass was identified and diagnosed as small-cell pulmonary neuroendocrine carcinoma.
• GCA manifestations were corticosteroid-dependent, with relapse upon tapering, and brain metastases developed despite oncologic treatment.

Conclusions:

• The presentation suggests a paraneoplastic mechanism linking GCA and lung neuroendocrine carcinoma.
• This case underscores the need for vigilance for underlying cancer in patients with refractory or atypical GCA.
• Recognizing paraneoplastic GCA can aid in early cancer detection and guide multidisciplinary management.