Overall cohort and statistical analysis
There were 101 (70%) males and 24 (17%) females; gender was not reported in 18 (13%) patients. The average age at diagnosis was 4 years (11 days – 18 years). Patients with a surgically excised cystic ECT were significantly older than patients with either a conservatively managed solid ECT or a surgically excised solid ECT (p < 0.0001). A total of 119 (79%) lesions were found in the neck: right neck 48 (41.5%), left neck 66 (55.5%), unspecified neck 5 (4%). The median lesion volume was 19.8 (0.01 – 1308) mL: patients with a surgically excised cystic ECT had significantly larger lesion than patients with a conservatively managed solid ECT or a surgically excised solid ECT (p = 0.0007). There was no difference in size between lesions located in the neck and other anatomical areas (p = 0.18) and between right and left neck (p = 0.6).
The presence of normal mediastinal thymus was investigated in 40 (28%) patients and found to be present in 39 (97.5%). For the remaining 103 patients there was no information regarding if the presence of normal mediastinal thymus was investigated.
Overall, for the 106 ECT cases that were excised we did not find ECT as preoperative differential diagnosis in the 54 manuscripts analysed. FNAC/biopsy were performed in 25 (5.6%) cases: correct diagnosis of ECT was obtained in 12 (48%) cases. Regardless of the type of ECT, post-operative complications included vocal cord paresis (2), hypocalcaemia (1), seroma (1).4, 5, 9, 68 There were no documented reports of malignancy on histological analysis of any type of ECT. Overall follow-up which was available for 36 (25%) patients, was 0.7 years (2 weeks – 6 years).