Intradiaphragmatic bronchogenic cyst

CASE REPORT

Intradiaphragmatic bronchogenic cyst

Fernando Luiz Westphal^I (te sbct); Arteiro Queiroz Menezes^II; Ricardo Alexandre Gonçalves Guimarães^III

^IThoracic Surgeon, Doctor in Medicine, Universidade Federal do Amazonas. Specialist degree from the Brazilian Society of Thoracic Surgery.

^IIThoracic Surgeon, Universidade Federal do Amazonas.

^IIIPathologist, Universidade Federal do Amazonas.

^{Correspondence}

ABSTRACT

The bronchogenic cyst is a common congenital malformation, generally located in the mediastinum; however, it can develop in other areas, such as the diaphragm. A rare case of intradiaphragmatic bronchogenic cyst is described here, discovered in a 32 year-old patient, who experienced thoracic pain and dyspnea following thoracic trauma. The pre-operative exams were compatible with left diaphragmatic hernia. The patient was submitted to a left post-lateral thoracotomy with the operative discovery of a cystic lesion enveloped by the diaphragm with mucinous content, and a partial resection of the diaphragm was performed. The histological findings of the operated portion revealed ciliated cylindrical epithelium, compatible with bronchogenic cysts. The post-operative outcome was excellent.

Key words: Bronchogenic cyst. Diaphragm. Diaphragmatic hernia.

Abbreviations used in this paper

POD – Post-operative day

ACT – Axial computerized tomography

Introduction

Bronchogenic cysts are the most ordinary congenital alterations of the mediastinum, being their etiology related to a defective development of the primitive intestine ⁽¹⁾, They are usually located in the paratracheal, carenal, hilar and paraesophageal areas, and can also occur in other places, such as anterior mediastinum and pericardial cavity ⁽²⁾. One of the most rare occurrences of this abnormality is diaphragm impairment, and it can simulate other diagnoses ^(3-5). The purpose of this report is to present a case of such abnormality, in addition to making a review of the diagnostic methods of diaphragm diseases.

Case Report

Thirty two year-old, woman, looked for medical assistance two days after a deceleration-induced trauma during a fall in a "water cylinder" (standing up), with thoracic pain and effort-induced dyspnea. At the physical examination, she presented reduction of the vesicular murmur at the basis of the left hemithorax.

Thoracic X-ray showed a hypotransparent image in posterior topography at the basis of the left hemithorax, whereas thoracic computerized tomography revealed images with hydroaerial levels at the lower third of the same hemithorax (Figure 1).

Taking into consideration the possibility of diaphragmatic hernia associated to the trauma and the patient’s symptoms, she was submitted to a left postero-lateral thoracotomy, where the operative finding was a cyst of intradiaphragmatic location, in the posterior portion, with mucinous content (Figure 2). After resection of the lesion, a diaphragmatic defect was observed, with approximately 5.0 cm in diameter, which was corrected by means of non-absorbable suture stitches anchored in prolene mesh. The patient was dismissed on the 4^th POD without complications, and was assymptomatic until the last ambulatory consultation, five months after the surgery. The hystopathological diagnosis of the lesion was of a bronchogenic cyst (Figure 3).

Case Discussion

Bronchogenic cysts result from the sequester of cells of the laryngotracheal sulcus, between the 26^th and 40^th day of intra-uterine life ^(2,6,7). They are covered by columnar ciliated epithelium and may have mucous glands or cartilage on their wall ^(2,8). They are more often discovered in the 3^rd or 4^th decade of life, as observed in this report, and are slightly more common in men ^(2,9).

Most of the bronchogenic cysts do not communicate with the tracheobronchial tree. Fifty to 80% of the patients are symptomatic at the time of the diagnosis, although the incidental finding at the X-ray is not unusual. The most common symptoms are pain, cough, fever or dyspnea ⁽⁹⁾. In this case, the cyst was an occasional finding at the X-ray resulting from the trauma referred by the patient. The bronchogenic intradiaphragmatic cyst is a rare pathology, and the first recordings were made by Buddington, in 1957⁽⁵⁾.

The imaging diagnostic of diaphragmatic diseases is made difficult due to its slim structure and curvilinear form. Usually, the X-ray is the first exam to be asked; however, it has high sensitivity and low specificity. Radiological alterations observed in this case were completely unspecific. The use of fluoroscopy allows the identification of functional alterations of the diaphragm, such as paralysis, aiding the diagnosis of pathologies that cause elevation of the diaphragmatic half-dome ⁽¹⁰⁾.

Axial computerized tomography has a greater diagnostic accuracy; however, diaphragmatic areas in contact with the liver and spleen are obscure, making it difficult to visualize alterations in these areas. On the other hand, this diagnostic method provides more information in places with adipose tissue. Tomography findings in the present case were compatible with diaphragmatic hernia, given the presence of hydroaerial level; nonetheless, the diagnosis was mistaken ⁽¹⁾. The advantage of the helical ACT is the coronal and sagittal reconstruction with the possibility of visualizing the phrenic domes ⁽¹²⁾.

Magnetic resonance imaging has the same advantage of the helical ACT in making coronal and sagittal slices, precisely determining the location of juxta- or intradiaphragmatic mass, being therefore used in the traumatic rupture and congenital hernia pre-operative diagnosis ⁽¹³⁾.

The diaphragm may be a site of development of mesothelial and neurogenic-derived tumors. The symptoms of the diaphragmatic impairment are not characteristic, and approximately 50% of the patients are assymptomatic at the time of the diagnosis. The feeling of weight in the lower part of the thorax or pain in the shoulder may occur ⁽¹²⁾. The symptoms presented by our patient were thoracic pain and effort-induced dyspnea, and this association has not been reported in the literature.

In general, treatment of diaphragmatic lesions demand a partial resection of the adjacent muscles, requiring reconstruction with synthetic prosthesis. When the location of the lesion is juxtacostal, anchorage stitches need to be used on the ribs and skin. The use of non-absorbable suture threads and separated stitches are recommended. In the present case, we observed that the lesion was involved by the diaphragmatic muscle, being a partial resection and reconstruction with prolene mesh necessary ^(10,11).

In conclusion, although bronchogenic cyst is a rare pathology, it is necessary to include it in the differential diagnosis of diseases which affect the diaphragm.

Received for publication on 2/4/2003

Approved, after revision, on 4/11/03.

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*

Work carried out at the Universidade Federal do Amazonas, Manaus, AM.

Publication Dates

• Publication in this collection
  24 Sept 2003
• Date of issue
  June 2003

History

• Received
  04 Feb 2003
• Accepted
  11 Apr 2003