This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Haematology, Subject name: Pathology
[{'content': 'A patient presents with mediastinal mass with sheets of epithelial cells giving arborizing pattern of reactivity alongwith interspersed lympoid cells. The apt diagnosis would be - \nSelect and explain. \nA. Thymoma, B. Thymic carcinoid, C. Primary mediastinal lymphoma, D. Non-Hodgkin lymphoma', 'role': 'user'}, {'content': 'Answer: A \nExplanation: A thymoma is a tumor originating from the epithelial cells of the thymus that may be benign or malignant. Thymomas are frequently associated with the neuromuscular disorder myasthenia gravis;thymoma is found in 20% of patients with myasthenia gravis. Once diagnosed, thymomas may be removed surgically', 'role': 'assistant'}]