Tireoidite linfocítica - Repositório Aberto da Universidade do Porto

I-SUMMARY AND CONCLUSIONS
The autoimmune nature of lymphocytic
thyroiditis has beeen advanced in 1956, after
the demonstration of thyroglobulin precipitins
in patients with Hashimoto's goitre. Several resear­
ches have, thereafter, confirmed the pioneer
studies of Doniach and Roitt. Despite this and
the great progress made in the field of immunology,
the pathogenesis of such thyroid disorder remains
controversial. In this essay we tried to obtain
a thorough and coherent understanding of the
lymphocytic thyroiditis in an attempt to contribute
to the clarification of the aforementioned contro­
versy.
Our material includes 161 cases of
lymphocytic thyroiditis diagnosed in surgical spe­
cimens (n=U9) and in autopsies (n= 12), as well
as 37 cases of diffuse hyperplastic goitre morpholo­
gically and clinically compatible with Craves'
disease. Every case was studied by light microscopy
using whenever necessary special stains. Immuno-
cytochemistry to detect immunoglobulines and/or
thyroglobulin was performed in 47 cases. Forty
five cases were also studied by electron microscopy.
Electron microscopy was also used in the study
of kidney glomeruli of 12 cases of lymphocytic
thyroiditis found at autopsy.
The following results were obtained:
A - Morphological and epidemiologic charac­
teristics
Lymphocytic thyroiditis:
- It occurs more frequently in the fifth
and sixth decades of life and is almost
exclusively found in the females.
- It is significantly more frequent in
the coastal region than in the interior.
- The oxyphilic transformation occurs
in late stages in the evolution of
the disease.
- The weight of the thyroid gland is
not significantly influenced by the
intensity of the lymphoid infiltrate.
- "Crowing nodules" often develop
and are more frequently observed
in patients living in the coastal region.
- There is a significant or suggestive
relationship between the oxyphilic
transformation and the abundance
of lymphoid infiltrate, septal fibrosis
and "growing nodules". There is also
a significant relationship between
the abundance of lymphoid infiltrate
and septal fibrosis.
- No evidence of evolution from focal
to diffuse forms of lymphocytic thyroi­
ditis is found.
Diffuse hyperplasia:
- It occurs more frequently during
the period between ten and fifty
years old and in the female sex, though
not as much as lymphocytic thyroiditis.
- The prevalence is similar in coastal
and interior regions.
- Oxyphilic transformation may occur
in small foci or small nodules, but
is generally much less frequent than
in lymphocytic thyroiditis.
-"Growing nodules" are seen less frequen­
tly than in lymphocytic thyroiditis
- Fibrosis, contrarily to what occurs
in lymphocytic thyroiditis, is practically
confined to interlobular septa.
B - Immunocytochemical study
Immunoglobulins
Lymphocytic thyroiditis:
- Most "Ig positive" cells are found
either dispersed throughout the lym­
phoid infiltrate or in perifollicular
areas. Rarely, a few "Ig positive"
cells were also seen within germinal
centers.
- "IgG positive" cells are much more
frequent (83 ±796) than "IgA (11 ±696)
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