Recombinant Human Thyrotropin for Management 8 of Metastatic Differentiated Thyroid Carcinoma in Patients With Deficient Reserve of Endogenous Thyrotropin

adioiodine (RAJ) therapy for metastatic R follicular cell-derived thyroid cancer(FCDe) requires elevated levels of serumTSH, usually achieved by withdrawalof thyroxine therapy. This is not possiblein FCDC associated with hypopituitarism, becauseof the absence of endogenous TSH. However,the advent of recombinant human TSH(rhTSH) has made diagnostic 1311 whole bodyscans and subsequent RAJ therapy possible forpatients with FCDC who have deficiency of endogenousTSH. Recently, several reports havebeen published of patients with metastaticFCDC and pituitary tumor treated after rhTSHadministration. We describe 2 cases of FCDCwith hypopituitarism, in which therapeutic RAIintervention was possible only with rhTSH administration.Materials and Methods: We searched our medicalrecords from 1950 through 1999 to determinethe prevalence of FCDC metastases to the pituitary.Results: We identified 19 cases of FCDC withconcomitant hypopituitarism but only 1 withmetastasis of FCDC to the sellar region. Of the 19 patients, 2 were treated with rhTSH beforeRAI therapy.Conclusions: Although metastasis of FCDC tothe pituitary is rare as shown by our study, associationof pituitary insufficiency with FCDC ismore common. The availability of rhTSH hasimproved th erapy fo r these patients.