<prompt> Fibrosis are seen in all except :-Marjolins ulcersBuruli ulcerVenous ulcerPeptic ulcer  <response>: Ans. b Buruli ulcerRef: SRB Manual of Surgery 23rd ed.23 Buruli ulcer is an infectious disease caused by Mycobacterium ulcerans. The early stage of infection is characterised by a painless nodule, with non- pyogenic, necrotizing lesions developing in the skin, and occasionally in adjacent bone, as the disease progresses. M. ulcerans secretes a lipid toxin, mycolactone, which functions as an immune suppressant, necrotising agent and activator of cellular apoptosis in mammalian tissues. The disease is primarily an infection of subcutaneous fat, resulting in a focus of necrotic dead fat containing myriads of the mycobacteria in characteristic spherules formed within the dead fat cells. Skin ulceration is a secondary event. All other ulcers are associated with significant scarring in the tissues. Scarring in gastric ulcerduodenal ulcer leads to gastric outlet obstruction. 