yesteraday 37 year corporate employee presented with history of sudden pain and sweeling of medial side of thigh mid.,,after getting from the bed.he was alright till the night.after getting from the bed he found pain and swelling no h/o insect bites no h/o sexual acts onset is acute.He went coroporate hospital and investigated throughly .All profiles were normal including coagulation.MRI of right the reported as haematoma of right thigh.I&D was done .and now he is ok.No H/o injury,playing games,quarrles.What could be the reason for such a sudden onset of haematoma