Fine Needle Aspiration Cytology of Malignant Thymoma - Two cases of Invasive Thymoma and Thymic Carcinoma -

악성 흉선종의 세침흡인 세포학적 소견 - 침윤성 흉선종 2례와 흉선암종 2례 -

We report 4 cases of malignant thymoma which were composed of 2 cases of invasive thymoma and 2 cases of thymic carcinoma. The cytologic findings of invasive thymoma were similar to those of benign thymoma. The distinctive cytologic features of thymic carcinoma were necrotic background, irregular clusters and individually scattered arrangement of anaplastic epithelial cells, and some scattered mature small lymphocytes. These findings may be found in the Hodgkin's lymphoma, seminoma, and metastatic squamous ceil carcinoma, undifferentiated carcinoma, and large ceil carcinoma of the lung. But, the feature of irregular clustering of anaplastic epithelial cell haying scanty cytoplasm was different from Hodgkin's lymphoma and seminoma. Clinical and radiologic findings as well as cytologic finding were helpful in differential diagnosis of thymic carcinoma from metastatic carcinoma.