Int J Thyroidol.  2016 May;9(1):51-54. 10.11106/ijt.2016.9.1.51.

A Case of Paratracheal Air Cyst Mimicking an Upper Esophageal Diverticulum

• Yoon JH
• Kim SJ
• Kim HK
• Kang HC

• KMID: 2164918
• DOI: http://doi.org/10.11106/ijt.2016.9.1.51

Abstract

Paratracheal air cyst (PTAC) is a small air collection in the right paratracheal area and mainly diagnosed by computed tomography (CT). Increased with ultrasonographic (US) screening of the thyroid, PTAC can be detected incidentally. However, the US findings of PTAC have not been well described. Herein, we report our experience with a rare instance of a PTAC. A 64-year-old female was referred to our hospital for fine-needle aspiration (FNA) cytology of a thyroid nodule. The lesion was identified as an ovoid, hypoechoic lesion with internal hyperechoic foci, abutting on the inferior pole of the right thyroid lobe. The margin was smooth without hypoechoic rim, which is typical in upper esophageal diverticula. US-guided FNA suggested a benign bronchial epithelial lining cyst. If a hypoechoic neck mass containing air without a thick hypoechoic rim is observed, especially at the right side of the trachea, the possibility of PTAC should be considered.

Keyword

Paratracheal air cyst; Ultrasonography; Computed tomography; Esophageal diverticulum; Fine-needle aspiration cytology

MeSH Terms

Biopsy, Fine-Needle
Diverticulum, Esophageal*
Female
Humans
Mass Screening
Middle Aged
Neck
Thyroid Gland
Thyroid Nodule
Trachea
Ultrasonography

Figure

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  Fig. 1. Ultrasonography (US) findings of the lesion. (A) A transverse US scan of the inferior pole of the right thyroid lobe shows a 0.9×0.4×1.1-cm-sized hypoechoic mass with internal hyperechoic dots (arrowheads), just lateral to the trachea. (B) On longitudinal scan, the lesion showed a linear hyperechoic focus with ring-down artifact (arrow), suggesting the presence of air. A hypoechoic boundary zone typically present in esophageal diverticula is absent.

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  Fig. 2. Fine-needle aspiration cytology revealed ciliated columnar epithelial cells (inset) in the lymphoid background with no follicular epithelial cells (Papanicolaou stain, ×200).

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  Fig. 3. (A) Neck computed tomography (CT) showed an air-filled cyst (arrowhead) in the posterolateral aspect of the trachea. (B) Anatomic location of the lesion (arrow) is displayed in a reconst-ructed coronal CT image.

Reference

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