Retroperitoneal bronchogenic cyst with fluid‑fluid level: A case report and literature review

Abstract

Bronchogenic cyst is a benign lesion with congenital dysplasia. Although the occurrence of this type of cyst is rare in the retroperitoneum, the presence of fluid-fluid levels is an even rarer phenomenon in bronchogenic cysts. Therefore, it can be easily misdiagnosed due to the lack of a universal guideline of specific imaging manifestations. The present report describes the case of a patient with a bronchogenic cyst with fluid-fluid levels whilst also performing a brief literature review to summarize the findings of previous reports on this condition. A 48-year-old male individual presented with severe lower back pain without any obvious causes. A CT scan revealed a low-density cystic mass of ~3x4x6 cm in the left front of the T12-L2 area, which originated from the left crus of the diaphragm. MRI revealed a fluid-fluid level in the cyst. Anterior thoracolumbar surgery was performed to completely resect the mass. During the surgery, it was confirmed that the cyst originated from the left crus of the diaphragm and the lesion was diagnosed to be a bronchogenic cyst by pathological analysis. The patient's symptoms improved after the surgery and no recurrence of the cyst was observed during the 3-year follow-up period. The presence of a fluid-fluid level in a retroperitoneal bronchogenic cyst is rare, particularly in the abdominal aorta and paravertebral regions, rendering it easily misdiagnosed. It may be associated with protein, hemorrhage and calcium-containing mucus deposition in the cysts. In the present study, a rare case of fluid-fluid level in bronchogenic cyst was reported and a literature review was provided.

Keywords: anterior thoracolumbar surgery; bronchogenic cyst; case report.

Figure 1

CT angiography of the abdominal aorta. (A) Coronal imaging revealed a low-density cystic mass with a Hounsfield units value of 30 on the left front of the T12-L2. The size of the cyst was determined to be ~3x4x6 cm. The lower part of the cyst is adjacent to the left renal artery and the medial part is adjacent to the abdominal aorta. (B) Upper cross-sectional imaging indicated that the cyst slightly compressed the abdominal aorta and originated from the left diaphragmatic crus, with the upper part located in the retrocrural space. (C) Middle cross-sectional imaging revealed that the lower part of the cyst extended into the retroperitoneal space. (D) Cross-sectional imaging below indicated that the lower edge of the mass was adjacent to the left renal artery.

Figure 2

Enhanced MRI images. (A) A cyst located in the retroperitoneal area originating from the left diaphragmatic crus, close to the spine and the right side of the abdominal aorta. (B) The fluid-fluid level was visible in the cyst. The cyst compressed the right side of the abdominal aorta was mildly compressed, with higher fluid signal values in the upper layer and lower signal values in the lower layer. Enhanced scan revealed that the cyst wall was smooth with no enhancement of cyst contents, but there was mild enhancement of the cyst wall.

Figure 3

H&E staining histopathological examination. (A and B) The cyst wall was covered with well-differentiated, pseudostratified and ciliated columnar epithelial cells. There were numerous cartilages and blood vessels in it and inflammatory cells had infiltrated. (A) magnification, x100 and scale bar, 400 µm. (B) Magnification, x400 of (A) and scale bar, 100 µm. (C and D) Cartilages and bronchial glands were found under the epithelium but no blood cells or calcium components were observed within the cyst. (C) Magnification, x100 and scale bar, 400 µm. (D) Magnification, x400 of (C) and scale bar, 100 µm.

Figure 4

No recurrence of the cyst can be observed with a T2-weighted imaging scanning on the sagittal were conducted during a 3-year follow-up period. (A) Pre-operation (fluid-fluid level indicated by arrow). (B) Immediately after, (C) 3 months, (D) 1 year and (E) 3 years after the operation.