Objective: Since the relationship between thymic hyperplasia (TH) and Graves Disease (GD) is of paramount importance for diagnostic and therapeutic choices, a wider knowledge of this association is required for endocrinologists in routine clinical practice. Our aim was to assess the prevalence, the clinical features, and the response to treatment of GD-related TH in an Academic referral centre.
Methods: All consecutive cases of GD-related TH at University Hospital L. Vanvitelli between January 2019 to December 2021 were retrospectively reviewed. Cases could be included whether: a) TH was initially suspected by symptoms or neck ultrasound (nUS) but confirmed and followed-up also by neck and chest (nc) computed tomography (CT)/magnetic resonance (RM); b) the imaging follow-up time was at least of six months; c) we had complete data at diagnosis of GD and after therapy (i.e., demographic, clinical, laboratory and imaging details).
Results: Among 144 newly diagnosed GD patients, TH was detected in six patients (6/144, 4.2%). Patients with GD-related TH were female with mean age 34.7 years (age range 23-48 years). Typical cardiovascular and neurological symptoms of thyrotoxicosis were the reasons for the consultation, and mild ocular involvement was present in three patients. No other pathologies affected our patients but multiple sclerosis was previously diagnosed in one case. At nUS mean thyroid volume was 25.2 ml (range 14-36 mL). Mean laboratory values were: fT3 12.5 pmol/l (range 11-18 pmol/l), fT4 32.2 pmol/l (range 28-40 pmol/l), thyrotropin receptor antibodies (TRAb) 9 IU/l (range 5-16 IU/l, positive ≥ 1.5 IU/l). In all the six cases TH was asymptomatic and initially identified by nUS as a hypoechoic (relative to thyroid tissue) trapezoidal mass with smooth margins and a reticulated pattern located at jugular notch with partial extension in superior mediastinum. In all the six cases confirmation of TH was obtained by the ncRM, which displayed at T2 images a homogeneous well-defined and lobulated soft tissue mass in the mediastinal prevascular space dislocating epiaortic vessels with a mean maximum diameter of 50 mm (range 44-56 mm) that disappeared after therapy. The average time for TH disappearance was nine months (range 6-14 months), and this was obtained after euthyroidism restoration (i.e. two cases by methimazole, three cases by radioiodine and one case by surgery).
Conclusion: Based on our experience, thymic hyperplasia was not infrequent in the GD setting and it was incidentally detected at nUS. TH regressed with the treatment of GD along with euthyroidism restoration.
21 May 2022 - 24 May 2022