Incomplete border sign.
A chest radiograph of a 42-year-old woman for employee health check-up showed a near normal appearance. However, there is a rounded radiopacity in left upper quarter which overlapping with the clavicle and the first rib by an incomplete border (Figure 1a, incomplete border sign). Computed tomography (CT) revealed a well-defined nodule protruding from the posterior chest wall (Figure 1b). CT-guided biopsy …