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Transsphenoidal microsurgery for prolactin-secreting pituitary adenomas.

The authors present the results of transsphenoidal microsurgery in 100 women with the amenorrhea-galactorrhea syndrome caused by pituitary adenomas associated with hyperprolactinemia (prolactinomas). As the surgical results were closely related to the preoperative levels of serum prolactin, the patients were divided into two groups: patients with preoperative prolactin less than 200 ng/ml (Group 1), and those with preoperative prolactin greater than 200 ng/ml (Group 2). The results in Group 1 (72 patients) were significantly better. In this group, 56 (78%) patients regained normal menstrual cycles, and 55 (76%) had return of elevated prolactin to normal following surgery. In Group 2 (28 patients), however, only 11 (39%) resumed normal menstrual periods postoperatively, and 13 (*46%) had return of elevated prolactin levels to normal. There was good correlation between tumor size and the preoperative level of prolactin. Of the 72 women in Group 1, 58 (81%) had tumors less than 1 cm (microadenomas), whereas of the 28 women in Group 2, only four (14%) had tumors of that size. All patients with visual field deficits preoperatively improved or had a normal visual examination postoperatively; none was made worse by surgery. Four patients (three in Group 2) have required additional surgery and/or irradiation. In the last six patients of the series, contrast-enhanced coronal computerized tomography slices made with the updated General Electric scanner detected five microadenomas. Considering that a relatively high percentage of sellar polytomograms are negative in patients with proven microadenomas (that is, only 40 of 72 patients in Group 1 has abnormal polytomography), it is likely that sellar polytomography will significantly decrease in importance in the diagnostic work-up of these patients. The authors provide a rationale for transsphenoidal microsurgery in these patients as opposed to other forms of management, such as bromocriptine therapy and irradiation.

Adenoma↗

Induction of hyperparathyroidism by radioactive iodine.

External irradiation to the head and neck has been associated with the emergence of hyperparathyroidism, due both to adenoma and hyperplasia since a single case report was published in 1975. A recent report indicates that there may be some association between hyperparathyroidism and radioiodine administered for thyroid disease. Eight patients are presented herein, all female and in middle age, who presented with hyperparathyroidism due to adenoma (six patients) or hyperplasia (one patient who had undergone radioiodine treatment). In three patients, the dose of radioiodine exceeded 30 mCi. The duration of latency ranged from 4 to 20 years. Associated thyroid disease included cancer, colloid nodules, and thyroiditis. All patients became eucalcemic and have remained so. Experimental results that have supported the influence of radioiodine on parathyroid hyperactivity do not appear completely applicable to the human model. It is believed that the low mitotic rate equivalent to low radiosensitivity may have protected the parathyroid gland somewhat from neoplastic change, although the association of thyroid carcinoma and parathyroid adenoma appears to be a significant expression of radiation exposure. It may be the lack of a pituitary-stimulating hormone and the absence of an abscopal mechanism, as illustrated by irradiation to the thyroid, that explains the relative immunity of parathyroid behavior in the face of radioiodine exposure. Regardless of the frequency and validity of the association, it is important to recognize the possibility of the association illustrated by our case reports and scrutinize appropriate patients by intermittent serum calcium sampling, both for confirmation and possible detection of occult hyperparathyroidism.

Adult↗

Treatment planning comparison of conventional, 3D conformal, and intensity-modulated photon (IMRT) and proton therapy for paranasal sinus carcinoma.

PURPOSE: To determine the potential improvements in patients with paranasal sinus carcinoma by comparing proton and intensity-modulated radiotherapy (IMRT) with conventional and conformal photon treatment planning techniques. METHODS AND MATERIALS: In 5 patients, comparative treatment planning was performed by comparing proton plans and related conventional, conformal, and IMRT photon plans. The evaluations analyzed dose-volume histogram findings of the target volumes and organs at risk (OARs, i.e., pituitary gland, optical pathway structures, brain, nontarget tissue). RESULTS: The mean and maximal doses, dose inhomogeneities, and conformity indexes for the planning target volumes were comparable for all techniques. Photon plans resulted in greater volumes of irradiated nontarget tissues at the 10-70% dose level compared with the corresponding proton plans. The volumes thereby increased by a factor of 1.3-3.1 for conventional, 1.1-3.8 for conformal, and 1.1-3.7 for IMRT. Compared with conventional techniques, conformal and IMRT photon treatment planning options similarly reduced the mean dose to the OARs. The use of protons further reduced the mean dose to the OARs by up to 65% and 62% compared with the conformal and IMRT technique, respectively. CONCLUSION: Compared with conventional treatment techniques, conformal RT and IMRT similarly enabled dose reductions to the OARs. Additional improvements were obtained using proton-based treatment planning modalities.

Humans↗