Fig

1.—-Tomogram

of case

1,

with

arrow

indicating erosion of sella turcica and mass
extending into sphenoid sinus.
Fable 1.—Serial Thyroid-Stimulating

Hormone’ (TSH) Levels in Two Patients
With Pituitary Tumors
Year

Case 1°

1965

2.2

1967

1.0

1969

1.7

1972

110

1973

Case 2

Lae
<2.5

Fig 2.—With immunoftuorescent staining,
dark cytoplasmic reaction product, indicated
by arrows, can be seen localizing prolactin in
cells of pituitary adenoma of.case 2. Prolactin-secreting cells have round to oval nuclei
and distinct nucleoli (X800).

Prolactin assays performed on stored
frozen sera obtained from her annual
examinations have revealed prolactin elevations ranging from 209 to 609 ng/mL as
far back as 1975, at which time she was 21
years of age.

wan

Results

1974

1.0

1975
1976

5.9
115

Lae

1978

1.8

1.7

1979

wae

0.3

1981

<2.5

<2.5¢

“Normal values are less than 5 pU/m_L.
tCase 1 had a total thyroidectomy in 1969 for
papillary carcinoma, and the elevated TSH levels in
1972 and 1976 were obtained when thyroxine therapy was discontinued prior to iodine 131 scanning.
+Year pituitary tumor was diagnosed.

turcica suggested the presence of a 1.2-cm
pituitary adenoma with no suprasellar
extension. Preoperative endocrine evaluation showed the following to be normal:
one-hour adrenocorticotropic hormone
(ACTH) stimulation test results, growth
hormone and cortisol responses to an
insulin tolerance test, free and total serum
thyroxine levels, and thyroid-stimulating
hormone values. Subsequently, transsphenoidal removal of an intrasellar adenoma
was performed. A soft-tissue tumor that
contained many small cystic foci was
found. Immunofluorescent staining of the
tumor was positive for prolactin (Fig 2).
Two weeks postoperatively, thyroid functions and results of a one-hour ACTH
stimulation test were normal, and serum
prolactin values had decreased to 68 ng/
mL. She remains amenorrheic one year
postoperatively.
JAMA, Aug 3,

1984—Vol 252, No. 5
a
Pal

201

K
u

14

Analysis of Epidemiologic Data.—
Incidencefigures for pituitary tumors
in the United States are not available
from the National Tumor Registry or
the National Cancer Institute’s Biometric Division because they are
not considered malignant. Several
studies suggest an incidence ap-

proaching one in 100,000 persons per

year among those younger than 45
years, distributed equally between
the sexes.” However, these retrospective studies occurred before modern
methodsof pituitary tumor diagnosis
were available.
Data from the Olmsted County,
Minnesota, epidemiologic study of
pituitary tumors’ and the 1970 and
1980 census information for that
county provide information that may
be used (as a referent) in comparison
with the Marshallese data. In
Olmsted County, the incidence rate of
pituitary tumors among women aged
15 to 44 years during the years 1971
through 1977 was 11 cases per 163,096
person years. For radiation-exposed
Marshallese women in the same age

2
11

2,176
163,096

2
12

4,252
454,472

risk, 13.6; 95% confidence interval, 4,
.01.
risk, 17.8; 95% confidenceinterval, 6,
.001.

group, the rate is two cases per 2,176
person years. The incidence rate for
the Marshallese womenis 13.6 times
higher than that for the Olmsted
County women; that is, the relative
risk, as estimated by the incidence
density ratio, is 13.6.’ If the propensity for pituitary tumors developing
were the same for each population
studied, then the relative risk should
be near unity, allowing for random
variation. An exact (binomial) test,

which is appropriate where numerators are small, indicates that the
relative risk is significantly greater
than unity at the a=0.01 level.
Table 2 provides relative risks, '
exact P values, and approximate confidence intervals for women aged
between 15 and 44 years and for men
and women combined who are younger than 45 years of age, using Olmsted
County as the referent population.
No allowance is made in the incidence data for any latent period in
tumor induction because there are no
published data on this point. The two
pituitary

tumors,

however,

were

clearly present 21 and 22 years after
radiation exposure. The statistical
analyses also ignore the fact that the
Marshallese people exposed to radioactive fallout have been followed
up more closely than any large control population. Finally, the baseline
frequency of pituitary tumors in the
Marshall Islands is unknown. While
no cases have been diagnosed in a
comparison population of unexposed
Marshallese, the number of personyears of observation is small (698
person-years for women aged 15 to 44
years; 1,527 person-yearsfor the total

population younger than 45 years).
This does not permit a meaningful’
statistical analysis of pituitary tumor
incidence in the Marshal! Islands.
Pituitary Tumors—Adams et al

665

7

"Relative
42; P value,
+Relative
53; P value,

Person
Years

RS

Women, 15-44 yr*
Marshail Islands
Olmsted County
Total population,
45 yrt
Marshall Islands
Olmsted County

incidence

.

Population

2 aegS RPI "ARRMo RE TSA, BaD eT MY Pt

Table 2.—Statistical Analysis of
Relative Risk of Pituitary Tumor in
Radiation-Exposed Marshallese

Select target paragraph3