Page 405 - Textbook of Pathology, 6th Edition

various patterns. The tumour consists of neoplastic Type 2 is also called thymic carcinoma and has cytologic 389
epithelial cells and variable number of non-neoplastic features of cancer. Further subtypes of epithelial
lymphocytes. Thymoma may be of following types: malignancy may be squamous cell type (most common)
Benign thymoma is more common. It consists of epithelial and lymphoepithelial type.
cells which are similar to the epithelial cells in the medulla Thymomas are known for their association with
of thymus and hence also called as medullary thymoma. paraneoplastic syndrome. These include: myasthenia gravis
Malignant thymoma is less common and is further of 2 (most common), hypogammaglobulinaemia, erythroid
types: hypoplasia (pure red cell aplasia), peripheral T cell leukae-
Type 1 is cytologically benign looking but aggressive and mia/lymphoma, multiple myeloma, other autoimmune
invades the mediastinal structures locally. disease associations and other systemic malignancies.

❑ CHAPTER 14

Disorders of Leucocytes and Lymphoreticular Tissues