Correct! 
3. The thoracic CT shows a mildly hyperattenuating mass in the subcarinal region extending inferiorly into the azygoesophageal recess

The thoracic CT shows normal pleural surfaces and the chest wall appears normal; no evidence of bone destruction or chest wall mass is present. A mediastinal mass, representing the lesion seen at chest radiography, is present, located in the subcarinal region. There is no evidence of either peribronchial or mediastinal lymph node enlargement outside the subcarinal region. The right pulmonary artery is normal in size, but is displaced laterally by the azygoesophageal mass.

The thoracic CT was inadvertently protocoled as an unenhanced examination, and therefore characterization of the lesion was incomplete. Attenuation measurements of the lesion shows that the lesion ranged in density from 38- 46 HU, which is consistent with complex fluid within a cyst, but could potentially be seen with a solid mass (Figure 5).

Figure 5. Axial unenhanced (A) and enhanced (B) thoracic CT in a patient with esophageal leiomyoma shows a lesion just posterior to the carina that is mildly hyperattenuating on the unenhanced image (A); attenuation coefficients measured about 45 HU. Following contrast administration (B), the lesion shows enhancement, confirming its solid nature. Axial enhanced image in a different patient (C) with surgically-proven esophageal leiomyoma shows a homogeneous mass that measures only 52 HU following intravenous contrast administration; a previous unenhanced study (not shown) revealed that this lesion measured about 32 HU prior to intravenous contrast administration. These cases underscore the need for unenhanced and enhanced imaging for proper characterization of some mediastinal masses.

Which of the following is the most appropriate next step for the management of this patient? (Click on the correct answer to proceed to the sixth of nine pages)

  1. 18FDG – PET scan
  2. Endoscopic ultrasound with biopsy
  3. Follow up enhanced thoracic CT in 3 months
  4. Repeat unenhanced and enhanced thoracic CT
  5. Unenhanced and enhanced thoracic MR

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