<prompt> 13, years old boy, the LEAST common cause of proximal lytic lesion of the head of the femur is -PlasmacytomaMetastasisHistiocytosisBone tumour  <response>: If multiple myeloma occurs as a solitary lesion it is known as PlasmacytomaAge gp is 6th-7th decade, Rare before 40yrs of ageSo the lytic lesion in a 13 yrs old boy cannot be a plasmacytoma 