Tireoidite linfocítica - Repositório Aberto da Universidade do Porto

and IgM (6 ± 596) positive" cells.
- The lymphoid infiltrate of the "growing
nodules" has immunocytochemical
characteristics similar to those of
the remaining infiltrate.
- Lymphoid infiltrate show an immuno­
cytochemical pattern of "reactive
type".
Diffuse hyperplasia:
- The immunocytochemical characteris­
tics of lymphoid infiltrate are similar
to those of lymphocytic thyroiditis.
Thyroglobulin
Lymphocytic thyroiditis:
- The positivity is more intense and
regular when the cyto-arquitectural
pattern is of hyperplastic type than
when it is of oxyphilic type, in which
there is often a striking variation
of positivity among the thyroid folli­
cles, as well as among cells of the
same follicle.
Diffuse hyperplasia:
- The positivity is generally intense
and quite regular, however it decreases
as the thyroid cells reduce their height
and the thyroid follicles increase
their diameter.
C - Ultrastructural study
Lymphocytic thyroiditis:
- Focal lymphocytic thyroiditis and
diffuse lymphocytic thyroiditis show
similar ultrastructural characteristics.
- It is possible to distinguish some
morphological types of epithelial
thyroid cells, but the variability of
the morphology is one of the most
remarkable features.
- The microvilli in the apical surface
of the thyroid cells are often short
and scarce.
- The basal surface of the thyroid cells
has a variable appearance. Cytoplas-
matic projections are frequently
found and often contain electrondense
structures suggestive of "degrading"
process.
- "Deposits" of immune complex type
are often seen near the basal lamina
of the epithelial thyroid cells. The
number and the sizes of these "deposits"
are variable.
- Most free cells in the lumina of the
thyroid follicles have the characteristic
features of macrophages.
- No glomerular "deposits" of immune
complex type were found in the kidneys
retrieved from autopsies.
Diffuse hyperplasia:
- Epithelial thyroid cells usually display
well developed rough endoplasmac
reticulum and long and numerous
microvilli. These morphological featu­
res are less prominent as the thyroid
cells reduce in height and the thyroid
follicles increase in diameter.
- The characteristics of the interface
epithelium-interstitium are similar
to those of lymphocytic thyroiditis:
the basal surface of the thyroid cells
displays cytoplasmatic projections
containing electrondense structures
with a "degrading" appearance and
"deposits" of immune complex type
can be seen near the epithelial basal
lamina.
The following conclusions were drawn
from the analysis of the results and the information
gathered from the bibliography:
At the morphological level:
- The oxyphilic transformation of the
thyroid cells is common in lymphocytic
thyroiditis but it is neither exclusive
nor constant.
- The variability of the morphological
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