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: Surgery
A 45-year-old male having a long history of cigarette smoking presented with gangrene of left foot. An amputation of the left foot was done. Representative sections from the specimen revealed presence of aerial thrombus with neutrophilic infliltrate in the aerial wall. The inflammation also extended into the neighbouring veins and nerves. The most probable diagnosis is: 
Select and explain. 
A. Takayasu aeritis, B. Giant cell aeis, C. Hypersensitivity angitis, D. Thrmoboangitis obliterans
D: Thrmoboangitis obliterans
Answer: D: Thrmoboangitis obliterans 
Explanation: Ans. is 'd' i.e. Thromboangitis obliterans About other options Takayasu's Aeritis : - does not involve the peripheral limb vessels. Its an inflammatory and stenotic disease of medium and large-sized aeries characterized by a strong predilection for the aoic arch and its branches (thus also k/a aoic arch syndrome) Giant cell aeritis: - also k/a cranial aeritis or temporal aeritis is a systemic chronic inflammatory vascular disease with many characteristics similar to Takayasu disease involves medium and large sized aeries, characteristically one or more branches of the carotid aery, paicularly the temporal aery. Hypersensitivity angitis (Ref. Harrison 16/e, p 2011; Internet: emedicine) hypersensitivity angitis also k/a cutaneous vasculitis or leukocytoclastic vasculitis typically involves the small vessels of skin. Post capillary venules are most commonly involved vessels; capillaries and aerioles are involved less frequently. its the most commonly encountered vasculitis in clinical practice. the hallmark of idiopathic cutaneous vasculitis is the predominance of skin involvement. Skin lesions typically are palpable purpura.