A Spot In The Lungs, Can U Suggest What The Exact Problem Is ?

hello doctor, A spot is detected in the lungs area of my mother her age is 55 years We have gone through various phase of tests, that are 1) X-Ray 2) CT -Scan Impression:CECT chest reveals hetrogenously enhancing mass lesion involving right lowe lobe with subcentimeter mediastinal lymphadenopathy possible mitotic in nature. 3)Bronchoscopy:Test is negative Now the doctor is suggesting for the CT guided biopsy Also We have gone through the MRI of head and the report is like this: Oblong ring enhancing lesion in the right fronto-parietal region associated with perilesional edema. the etiology is likely to be neoplastic and represent metastatis. But still the doctors are not able to conclude, what the exact problem is, they are now suggesting for biopsy can u suggest what the exact problem is ? weather we should go for biopsy or not? Is there is some better test which better then biopsy? Eagerly awaiting for your response Thanks Amit