Multiple atypical thymic carcinoids with paraneoplastic giant cell arteritis.

Multiple thymic carcinoids are rare, and giant cell arteritis (GCA) is one of the less recognized paraneoplastic diseases. The co-occurrence of these two diseases is therefore extremely rare. We report herein a patient with multiple atypical thymic carcinoids and asymptomatic paraneoplastic GCA. All the thymic carcinoids were diagnosed histopathologically as atypical thymic carcinoids with an intrathymic metastasis. Treatment consisted of a complete tumor resection followed by observation of the GCA without any adjuvant therapy. Subsequent positron emission tomography revealed a decrease in F-fludeoxyglucose accumulation in the systemic arteries. Based on these findings, paraneoplastic GCA was diagnosed. Thymic carcinoids rarely involve intrathymic metastasis or cause neopleonastic GCA. However, when they do, a complete tumor resection is the best option for management.