Localized Erdheim-Chester disease involving the thyroid gland—a case report

Abstract

Background Erdheim-Chester disease (ECD) is a rare multisystemic histiocytic disorder of unknown etiology. Isolated neck involvement has not been reported in literature. Case presentation An elderly male presented to our outpatient department with neck swelling of 1-month duration. Contrast-enhanced CT scan of the neck showed a mass involving the left thyroid/perithyroidal tissue with encirclement of the common carotid artery. Tru-Cut biopsy with immunohistochemistry showed CD68+, CD1a- histiocytic infiltrates with Touton giant cells compatible with ECD. BRAFV600E mutation came out to be positive. PET-CT did not reveal involvement of any other body organs. After counseling for further treatment options, the patient chose to follow up without any active treatment. The disease has not progressed at a follow-up of 1 year. Conclusion We present a case of ECD involving the thyroid gland in isolation. Absence of other organ involvement should not deter the treating physician from considering the possibility of ECD. Immunohistochemistry and testing for BRAFV600E mutation are important from the diagnostic as well as potential therapeutic point of view.