This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Pathology
[{'content': 'A 63-year old man presented with massive splenomegaly, lymphadenopathy and a total leucocyte count of 17000 per mm3. The flow cytometery showed CD 23 negative and C 5 positive monoclonal cells with bright kappa positively comprising 80% of the peripheral blood lymphoid cells. The most likely diagnosis is - \nSelect and explain. \nA. Mantle cell lymphoma, B. Splenic lymphoma with villous lymphocytes, C. Follicular lymphoma, D. Hairy cell leukemia', 'role': 'user'}, {'content': 'Answer: A \nExplanation: 65 years old man with splenomegaly, lymphodenopathy CD-23 negative and CD-5 positive B-cell suggest the diagnosis of mantle cell lymphoma.\n\nClinical features of mantle cell lymphoma \n\nIt is usually present in fifth to sixth decade with male preponderance.\nThe most common presentation is painless lymphodenopathy.\nSplenomegaly may occur.\nOccasionally, multifocal mucosal involvement of the small bowel and colon produces lymphomatoid polyposis → of all forms of NHL, mantle cell lymphoms is most likely to spread in this fashion.', 'role': 'assistant'}]