WHO histological classification of thymic tumors?
Thymomas are classified as type A thymoma (including an atypical variant), AB thymoma, type B thymoma (separated into B1, B2, and B3 thymomas), micronodular thymoma with lymphoid stroma, and metaplastic thymoma by histologic features and, rarely, immunohistochemistry, such as immature T cell content.
What is Type B thymoma?
The B2 type of thymoma is defined as a tumor in which the neoplastic epithelial component appears as scattered plump cells with vesicular nuclei and distinct nucleoli among a heavy population of lymphocytes by the World Health Organization (WHO) classification [2].
What is Type B1 thymoma?
Type B1 thymoma is defined as a tumour that resembles the normal functional thymus and combines large expanses indistinguishable from the normal thymic cortex with areas resembling the thymic medulla.
What is metastatic thymoma?
The metastatic tumor is the same type of cancer as the primary tumor. For example, if thymic carcinoma spreads to the bone, the cancer cells in the bone are actually thymic carcinoma cells. The disease is metastatic thymic carcinoma, not bone cancer.
Is thymoma Type B3 malignant?
Thymic carcinoma (TC) is a rare type of malignant neoplasm that develops in the anterior mediastinum and associated with poor prognosis. Type B3 thymoma (B3) occasionally demonstrates malignant tumor characteristics, especially in the advanced stage.
What is B3 thymoma?
Type B3 thymoma is also known as epithelial thymoma, atypical thymoma, squamoid thymoma, and well-differentiated thymic carcinoma. This type of thymoma has few lymphocytes, and the thymus cells look abnormal. Approximately 40% of people with this type live at least 20 years after diagnosis.
Is B1 thymoma malignant?
Type B1 thymoma is considered to a tumor of low-grade malignant potential since it is completely encapsulated in more than 50% of cases. Almost 90% of cases are considered completely resectable.
Do thymomas metastasize?
The present study demonstrated that 31% of patients with thymomas or thymic carcinomas had metastasis or recurrence, and a half of these patients developed three or more episodes of metastasis or recurrence during their disease course.
What does the who’s new thymus tumor classification mean for differential diagnosis?
In terms of differential diagnosis, the new WHO classification of tumors of the thymus clarifies some important diagnostic challenges that need careful immunohistochemical analysis:
What are the different types of cancer of the thymus?
Each kind can develop into different types of cancer: Epithelial cells give the thymus its structure and shape. Thymomas and thymic carcinomas, which are the main focus of the rest of this document, develop from these cells. Lymphocytes make up most of the rest of the thymus.
What is the thymus section?
This makes the thymus section of the new WHO Classification of Tumours of the Lung, Pleura, Thymus and Heart a valuable tool for pathologists, cytologists and clinicians alike.
What are the stages of thymic tumors?
It classifies thymic tumors into the following stages: Stage I: The cancer is located only in the thymus and the capsule that surrounds the thymus. Stage II: The cancer has spread into fat surrounding the thymus or into the lining of the lung next to the tumor, called the mediastinal pleura.