The first case report of diaphragmatic paralysis as a paraneoplastic syndrome of medullary thyroid carcinoma.

curves for proportion of patients who developed overt thyrotoxicosis according to aetiology showed no significant differences (P = 0Æ557; log-rank test). Results obtained in our patients are similar to those reported by Rosario, who found that progression to overt hyperthyroidism occurred in 20% of 30 women with Graves’ disease and in 40% of 15 women with nodular disease. On the contrary, Woeber found that only one of seven patients with Graves’ disease and none of nine patients with nodular disease developed overt hyperthyroidism. We have performed a chi-square analysis of available data form Rosario’s and Woeber’s reports, and did not find any significant relationship between aetiology and progression to overt thyrotoxicosis (P = 0Æ174 and 0Æ438 for Rosario’s and Woeber’s data, respectively; Fisher exact test). Discrepancies between these results and those recently reported by Schouten et al. may be accounted for by differences in the number of studied subjects and the time of observation, and also by differences in iodine intake, geographical location and genetic background of patients. It is our opinion that, although the aetiology of thyroid hyperfunction is essential in evaluating patients with thyrotoxicosis, the clinical relevance of the initial TSH should not be underestimated when assessing the risk of progression to overt thyroid disease. Furthermore, it should be noted that the presence of TSH < 0Æ10 mU/l has been associated with an increased risk of atrial fibrillation, cardiac dysfunction, and adverse effects on bone mineral density in postmenopausal women, and that most experts and scientific societies recommend therapy for older patients with TSH < 0Æ10 mU/l. In brief, we think that, in clinical practice, TSH concentration is a major factor in assessing the risk of progression to overt thyrotoxicosis. It is very probable that the aetiology of thyrotoxicosis is also a significant variable in the assessment of progression, but the importance of this variable might vary depending on geographic location of patients, iodine intake and possibly other variables.