Hi welcome to the health care magic This lytic bone lesion is not usual finding .... Here you have leg pain also... Hence first of all your neurological examination and serum B12 checked to rule out any neuropathy if present... Your detail physical examination, clinical history taken per rectal prostate palpation done as here metastatic bone lesion or multiple myeloma like condition has to be ruled out for being safer side If needed CBC, peripheral smear examination, serum protein electrophoresis can be done for rule out plasma cell dyscrasia... If malignancy suspected than biopsy needed If no malignancy suspected after examination and necessary report than other non malignant possibility has to be ruled out Hence consult surgeon or orthopedic surgeon for detail history taking and physical examination first according to which further investigation plan decided Take care