JMJ, female 7 days old with congenital hypothyroidism. Underwent 99mTc thyroid scintigraphy. There is no thyroid gland in the cervical region. All tracer was concentrated in the retro and sublingual space. Images obtained with 99mTc give similar information to the 131I scan, with better resolution. Kumar et al. reported an interesting case with Tc-99m sodium pertechnetate thyroid scan that showed dual ectopic thyroid glands in the sublingual and subhyoid regions (1,2).
If there is no possibility to withdraw thyroid hormone therapy, 99mTc-MIBI may be employed to visualize the gland (3).
References:
1) Degrossi OJ et al. Diagnóstico del Bocio Nodular, p: 691-176 and Wagner J et al. Diagnóstico y Tratamiento de las Malformaciones y Disfunciones del Tiroides p: 177-184 in: Medicina Nuclear Aplicaciones Clínicas. Eds: I. Carrio - P. González. Editorial Masson, Barcelona España, 2003.
2) Kumar R, Khullar S, Gupta R, Marwah A, Drm MA. Dual thyroid ectopy: case report and review of the literature.Clin Nucl Med. 2000 Apr;25(4):253-4.
3) Dragosavac S et al. 99mTc -Sestamibi in
differential diagnosis of congenital hypothyroidism in children under hormone
therapy. Alasbimn Journal 7(27): January 2005 (abstract).
http://www2.alasbimnjournal.cl/alasbimn/CDA/sec_a/0,1205,SCID%253D12837%2526PRT%253D12824%2526LNID%253D10,00.html