<prompt> Tumefactive lesions are seen most commonly in which disease?Reiters diseaseMultiple sclerosisPaget diseaseMarfan syndrome  <response>: Ans. B. Multiple sclerosisTumefactive multiple sclerosis is a condition in which the central nervous system of a person has multiple demyelinating lesions with atypical characteristics for those of standard multiple sclerosis MS.It is called tumefactive as the lesions are tumor-like and they mimic tumors clinically, radiologically and sometimes pathologically. 