The psoas fascia covers the ant surface of the psoas muscle and can influence the direction taken by a tuberculous abscess.tuberculous disease of the thoracolumbar region of the vertebral column result in the destruction of the vertebral bodies with possible extension of pus laterally under the psoas fascia from there the pus tracks downward following the course of the psoas muscle and appears as a swelling in the upper part of the thigh below the inguinal ligament it may be mistaken for a femoral hernia
I read that the TB and malignancy metastasis could present with same imaging so the biopsy solve the problem.
Malignancy metastasis spread from the primary site through blood and lymph so first itโs affected the liver and lymph nodes and maybe bones or lungs