REVIE\N ARTICLE

Mammographic
density of

breasts
The effect of

Iror'rrtorte therapy

A n increase in the density of the
breast parenchyma is a well described
entity as a result of hormone therapy.'
When an increase in mammographic
density occurs, this is an early event
which will start directly after the ad-
ministration of HRT. The most com-
mon cause of a diffuse increase in the
breast density, is weight loss.' The rea-
son for this seems to be a relative re-
duction in the mass of fatty tissue in
relation to the gland.

Generally speaking, it is unusual to
see variation in the density of breasts
in the same patient as a function of
time.

Oza reported in 1993 that alcohol
use has a positive independent effect
on mammographic density. This is due
to alcohol's effect of increasing oestro-
gen levels.'

Two cases are presented of patients
who received baseline mammograms
before the commencement of hormone
therapy and then underwent follow up
mammograms.

G Kruger
MMed(Pret)Radiology

Material
Two female patients of ages 58 and

62 years respectively received baseline
mammograms before the commence-
ment of hormone replacement therapy.
The first patient received a mammo-
gram after a year and the second pa-
tient after approximately 9 months.

On both follow-up mammograms
there was a diffuse non-specific increase
in the relative density of the breasts
with an absolute increase in the glan-
dular element of the mammograms
(Figures 1a and 1b) .

Neither patient experienced any
weight loss during the interval.

It has been reported that between
17 and 27% of patients will develop a
denser pattern on HRT. In practice
however, the incidence seems to be
much lower. According to Kopans the
incidence approaches 5% of cases.
Kopans further reports that in excep-
tional cases, cysts may form in the
breasts as a result ofHRT. The increase

16 SAJOURNAL OF RADIOLOGY. April 2000

Figure 1(a) and (b): The images on the top half
of the figures illustrate breast density before
HRT, and the bottom half after HRT.

in density of the breasts as a result of
hormone replacement can also follow
the administration of vaginal creams.

Discussion
The cases described are two exam-

ples of a diffuse increase in the glandu-
lar element of breast tissue following
hormone replacement therapy in post-
menopausal women. According to the
latest literature, the finding is more

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