What Do These Images Reveal?

1. Increasing neck fullness A 64-year-old woman complains of neck fullness that has increased in the last few months. She has occasional dyspnea but denies fever, cough, and hemoptysis. Hypertension is well-controlled with propranolol(. This mildly obese woman is in no acute distress. Temperature is 37.2^oC (99^oF); heart rate, 92 beats per minute; respiration rate, 18 breaths per minute; and blood pressure, 136/87 mm Hg. Heart and lungs are normal. The axillary and inguinal regions are normal. Palpation of the neck reveals mild diffuse fullness. You order frontal and lateral upright radiographs of the chest. What abnormalities do these films reveal, and how will you proceed to narrow the differential diagnosis?1. Increasing neck fullness: The films reveal fullness in the right paratracheal region, which is better seen on the high-resolution image of this area (A, arrow). The lateral radiograph (B) demonstrates fullness in the superior aspect of the middle mediastinum (black arrow); in addition, a lesion overlies the spine on this view (white arrow). The differential diagnosis of middle mediastinal lesions includes several conditions:

• Adenopathy. This is the most common cause; however, there is no evidence of hilar adenopathy here. In a patient this age, adenopathy would suggest metastatic disease. Lymphoma, fungal disease, and tuberculosis are other possibilities.
• Vascular lesions. Anomalous vessels can have an unusual appearance. Aneurysms can also cause mass lesions.
• Congenital lesions. Foregut malformations are commonly seen in the middle mediastinum; however, it is relatively uncommon to see them in its superior aspect.
• Thyroid lesions. Although these are typically encountered in the anterior mediastinum, they occasionally occur in the middle mediastinum.

You order a CT scan to narrow the differential. The CT images (C, D) reveal a mass contiguous with the thyroid (arrows)-which makes multinodular goiter the most likely diagnosis. This was confirmed on biopsy. CT also demonstrates the incidental lesion detected on the chest radiograph to be a large osteophyte of the thoracic spine, seen en face (E, arrow). This case illustrates 2 key points:

• Large masses can be overlooked if chest films are not carefully scrutinized.
• The trachea must be inspected on all films, and any deviation from the midline needs to be explained.

2. Sharp axillary pain A 39-year-old woman has had intermittent, sharp pain in her right axilla for 3 days. The pain worsens when she breathes deeply or moves, but it does not radiate. No associated diaphoresis, nausea, or vomiting. The patient also denies fever, shortness of breath, and sputum production. Medical history is significant only for hypertension; there is no family history of coronary artery disease or pulmonary embolism. The patient smokes 1 pack of cigarettes daily. Temperature is 37^oC (98.5^oF); heart rate, 102 beats per minute; respiration rate, 18 breaths per minute; and blood pressure, 144/85 mm Hg. Heart rate and rhythm are regular; no murmurs or jugular venous distention. Breath sounds at the right lung base are diminished. Bowel sounds are normal, and there is no abdominal tenderness. No leg tenderness or swelling is evident. White blood cell count, hemoglobin level, hematocrit, and electrolyte and cardiac enzyme levels are normal. An ECG demonstrates normal sinus rhythm with left ventricular hypertrophy and nonspecific ST changes. Arterial blood gas measurement reveals PO₂ of 81 mm Hg on room air and an alveolar-arterial gradient of 21. You order frontal and lateral radiographs of the chest. What finding on these films suggests the cause of the pain-and what further steps will you take to confirm the diagnosis?2. Sharp axillary pain: The radiographs show a peripheral wedgeshaped opacity within the right upper lobe, which is better seen on the high-resolution image of the area (A, arrow). A peripheral air-space opacity is also identified at the right lung base (B, arrow). These findings suggest pulmonary embolism. The peripheral wedge-shaped opacity represents infarcted lung distal to an occlusion of the more proximal pulmonary artery; this sign is called a "Hampton hump." Although this finding is relatively insensitive, it is specific for pulmonary embolism in the appropriate clinical setting (eg, acute onset of chest pain in a patient who has recently had surgery). Nonspecific radiographic findings include atelectasis, pleural effusion, and elevation of the hemidiaphragm. Typically, however, the chest film is normal in patients with pulmonary embolism. CT angiography confirmed the diagnosis (C, D). These images reveal a large thrombus in the right main pulmonary artery (C, arrow). The peripheral wedge-shaped airspace opacity is also evident on CT (D, arrow).