She wasreferred to the Republic of the Marshall Islands Health Service for further evaluation. The numberof persons evaluated is too small to derive a prevalence: of hyperprolactinemia among Marshallese. Therefore, this finding culosis. A tabulation of the prevalence of positive and negative tuberculin and Candida tests according to radiation group and island of residence at the time of testing is presented in Table 3. The results indicate that the prevalence of positive tuberculin tests and the prevalence of does not support or refute a conclusion that pathologic hyperprolactinemia and, by inference, prolactinomas are unusually common anergy, when analyzed by the chi-squaretest of independence between two or more samples, were similar among the radiation exposure groups. The frequency ofinfection with atypical mycobacteria among Marshallese is unknown. An analysis of size distribution of positive tests indicated 2- to 5-mm induration responses from 14.4% of all personstested, a finding compatible with past exposure to atypicals. among the general Marshallese population. Thyroid Hypofunction Subclinical thyroid hypofunction, as assessed by thyroid-stimulating hormone (TSH) determinations and responseto thyrotropin-releasing hormone (TRH), has been documented in 12 persons in the exposed Rongelap group (Larsen et al. 1982). Annual TSH testing has continued for this group, and biennial testing is provided Hyperprolactinemia Two exposed women have now been diagnosed as havingpituitary tumors (Adamsetal. 1984a). In the 1980-82 Brookhaven National Laboratory Marshall Islands report mention was made of another woman,82 years of age, who had mild but persistent serum prolactin elevations (Adamset al. 1984b). In 1984 this Utirik patient, No. 2182, was brought to for the Utink group. Of 61 persons in the Rongelap group, 57 had TSH levels determined in either or both 1983 and 1984. No new cases of biochemical hypothyroidism were uncovered. However, since all members of this group are advised to take suppressive doses of thyroid hormone (Synthroid), it is possible that new cases are still emerging but are being masked by the administered thyroid hormone. Accurate diagnosis would require the discontinuation of thyroid hormone for several weeks, followed by TSH assays and perhaps TRH stimulation tests. Because little clinical benefit for the Rongelap groupis likely, this approach has not been taken. The Utirik group received much lower thyroid radiation doses in 1954 than did persons on Rongelap, and no thyroxin suppression has been prescribed for them. Thyroid hypofunction has yet to be diagnosed in this group,and, of 104 persons tested in 1983-84, the only elevated TSH levels found were in four individuals who had previously undergone thyroid surgery. Hypothyroidism has numerousetiologies and Cleveland Metropolitan Hospital for surgery for a suspected thyroid nodule. The presence of the nodule was not confirmed preoperatively, however, and surgery was not performed. Advantage was taken of the availability of CT scanning facilities at the hospital to evaluate her fora pituitary lesion. A CT scan of the skull, with and without contrast, was read as suggesting a lesion within the sella turcica. However, the interpretation of Dr. Azad Anand, neuroradiologist at University Hospital, SUNY, Stony Brook, indicated that there is no evidence for a pituitary tumor. Therefore, although it remains possible that such a tumor exists, no diagnosis can be confirmed at the present time. Because the possibility of a third pituitary tumor in the small numberof exposed persons still under observation would be a clinical finding without precedent, a survey of serum prolactin levels was undertaken in the unexposed comparison group. Of 110 persons tested, five were found to have mildly elevated levels. Four of these were found to be normal on repeat testing. One woman had persistent mild elevation of serum prolactin (55 ng/ml). occurs not uncommonlyin all populations.Its spontaneous frequencyis age related, and 4.4% of a Massachusetts population over 60 years of age have been found to have clearly elevated TSH levels(Sawinet al. 1985). The prevalence of biochemical hypothyroidism in unexposed Marshallese was evaluated in 1984. Of 90 persons tested, no TSH elevations were detected. 10