This diagnostic image is an axial contrast-enhanced computed tomography (CECT) scan of the thorax at the level of the lower chest and upper abdomen. The image demonstrates significant pathology of the anterior chest wall involving the right fifth costal cartilage. Key findings include a focal soft tissue mass and associated thickening at the costochondral junction. Evidence of bony erosion and fragmentation of the costal cartilage is visible, suggesting an aggressive inflammatory or infectious process, such as tubercular costochondritis. Additionally, multiple well-defined, ovoid soft tissue density nodules (indicated by arrows) are present within the subcutaneous tissues of the anterior abdominal and chest wall, which can be seen in conditions like neurofibromatosis or disseminated granulomatous disease. The internal anatomy shows the heart, descending aorta, and the superior aspect of the liver. This scan illustrates the radiological presentation of extrapulmonary tuberculosis manifesting as chest wall involvement with secondary subcutaneous nodules.

This diagnostic image is an axial chest computed tomography (CT) scan with intravenous contrast. The focus is on the anterior left chest wall at the level of the lower mediastinum. An arrow indicates a focal area of pathology involving the left seventh costal cartilage. Key findings include localized soft tissue thickening and a hypoattenuating fluid collection approximately 0.9 x 0.6 cm in size, characteristic of an abscess or persistent fluid collection associated with costochondritis. There is evidence of a sinus tract extending from this deep collection toward the skin surface. Centrally, the mediastinum contains the heart and great vessels, with visible calcifications within the coronary arteries. The lungs are clear without significant consolidation or pleural effusion. The vertebral bodies and posterior ribs appear intact. This scan is educationally significant for demonstrating the radiological appearance of infectious costochondritis and associated chest wall abscess formation, which in this clinical context was confirmed to be caused by Salmonella enterica serotype Choleraesuis.

**Imaging Modality:** Greyscale Ultrasound (high-frequency linear transducer). **Anatomical Region:** Anterior chest wall at the costochondral junction. Key landmarks include the osseous rib (labeled 'R'), the sternum (labeled 'S'), and the intervening costal cartilage. **Observed Pathology:** Costal cartilage calcification. **Characteristic Visual Features:** The image displays a longitudinal view of the costal cartilage, which appears as a relatively hypoechoic, elongated structure. Within the cartilaginous matrix, multiple discrete, hyperechoic (bright) foci are visible (indicated by white arrows). These hyperechoic clusters represent areas of mineralization or calcification. The underlying cortical surfaces of the rib and sternum exhibit characteristic hyperechoic lines with distal acoustic shadowing. **Diagnostic Features:** The presence of scattered internal echogenicities within the normally hypoechoic costal cartilage is diagnostic of cartilaginous calcification. This finding is often associated with physiological aging or specific inflammatory conditions of the chest wall, such as costochondritis. The distribution is localized between the bony landmarks of the thoracic cage.