Akademik Veri Yönetim Sistemi
5. Uluslararası Bilimsel Çalışmalar Kongresi, Elazığ, Türkiye, 15 Mart 2021, cilt.1, ss.504-509
Introduction:Thyroid transcription factor-1 (TTF-1) is widely used to identify neoplasms originating
from the lung, particularly pulmonary adenocarcinomas in both intrapulmonary,extrapulmonary
regions.TTF-1, which has high specificity/sensitivity, shows less staining in neuroendocrine tumors.
Our aim in this study is to examine the staining pattern of TTF-1 in typical carcinoid tumors in the
lung together with the literature.Materials and Methods:In this retrospective study, patients diagnosed
with pulmonary carcinoid tumor in our department were investigated.Average age, location of tumor,
size of tumor were analyzed.Frozen assessment of tumor, differences in histopathological
appearance,TTF-1 expression by immunohistochemistry were evaluated.Results:26 of 38 patients
with neuroendocrine tumors had typical carcinoid tumors. Of these,11 were men(42.3%),15(57.7%)
were women.Age of patients ranged from 25 to 83, with a mean age of 56.2±14.4 years.Three of
patients were studied under frozen conditions.Since differential diagnosis with atypical carcinoid
could not be made clearly,it was reported as "neuroendocrine tumor".A definite diagnosis was made
in paraffin sections and all of them were reported as typical carcinoid tumors.While 12 of all typical
carcinoids showed peripheral localization,14 were centrally located.All of them were in form of a
solitary mass.Their diameter was between 1-5 cm.TTF-1 was applied to all of them.While 10 of them
were stained positively with TTF-1, no reaction was observed in 16 cases.There were 5 cases of
tumors with peripheral localization that were not stained with TTF-1;but 7 cases that stained positive
with TTF-1.In centrally localized tumors, 9 were negative; 5 of them showed a positive reaction with
TTF-1.Discussion / Conclusion: TTF-1 expression in carcinoids is specific for primary lung
neoplasms compared to those in thymus,extra-thoracic locations.However,if TTF-1 reacts negatively,
pulmonary origin cannot be precisely excluded.Although it has been reported that pulmonary typical
carcinoids show staining with TTF-1 with positivity ranging from 0% to 94%,TTF-1 positivity is
relatively lower for pulmonary neuroendocrine tumors as in our study.In addition,typical carcinoids
that are centrally located are stained negatively with TTF-1.Carcinoids with peripheral localized and
spindle cell morphology have higher TTF-1 positivity.This finding suggests that these tumors may be
histogenetically different based on their localization and TTF-1 staining pattern.