Micronodular thymic carcinoma (MNCA) is an extremely rare variant of thymic carcinoma. We described a 67-year-old woman, who was referred to our institution for a mediastinal mass. The magnetic resonance imaging (MRI) scan showed a 5.0 cm x 4.1 cm x 2.2 cm infiltrative mass invading adjacent tissue with central cystic change. Histologically, the neoplasm was composed of epithelial tumor cells arranged in a micronodular growth pattern set in a stroma showing lymphoid hyperplasia with germinal centers. Contrary to micronodular thymoma-the benign micronodular thymic neoplasm, the epithelial cell component of the present case showed malignancy characterized by cytological atypia, increased mitotic activity and immunoactivity of CD5 and CD117. The lymphoid component was mixed mature B- and T-cells. Langerhans cells proliferation were confirmed within epithelial nodules with langerin, S-100, CD1a expression. We report a case of MNCA to emphasize the histopathologic features and the Langerhans cells proliferation and differential diagnosis of the rare lesion to promote a better and broader understanding of the morphologic spectrum of micronodular thymic neoplasm.