Intradiaphragmatic bronchogenic cyst: report of a rare new case
- 1 Sarcoma and Melanoma Unit, General Surgery Department, British Hospital of Buenos Aires, Buenos Aires, Argentina
- 2 General Surgery Department, British Hospital of Buenos Aires, Buenos Aires, Argentina
- 3 Pathology Department, British Hospital of Buenos Aires, Buenos Aires, Argentina
- Correspondence to Dr Sergio Damián Quildrian; squildrian@intramed.net
Abstract
Bronchogenic cysts (BCs) are congenital abnormalities commonly found within the mediastinum. Diaphragmatic location is extremely rare. We present a woman in her 60s with an asymptomatic intradiaphragmatic BC. The patient underwent complete surgical resection with primary closure of the left hemidiaphragm. BCs should remain a differential diagnosis of any soft-tissue mass in the region of the diaphragm. Complete surgical resection is recommended even in asymptomatic patients to avoid complications such as infection, rupture, bleeding or malignant transformation.
Background
Bronchogenic cysts (BCs) are congenital malformations that arise from the ventral foregut due to an abnormal sprouting of the tracheobronchial tree.1 This is why they are usually located within the mediastinum or the lung parenchyma. In exceedingly rare cases they develop within the diaphragm. They rarely undergo malignant degeneration, but their presence demands a surgical resection.2 3 To our knowledge, less than 25 cases of intradiaphragmatic BCs have been reported in the English literature. Herein, we present a new case of an adult with BC whose lesion was resected via a laparotomy approach.
Case presentation
A woman in her 60s was referred to our surgical department due to a retroperitoneal mass found on abdominal MRI (figure 1C,D) performed following an incidental finding on a routine abdominal ultrasonography. Her medical history was significant only for dyslipidaemia and conventional appendectomy. She was asymptomatic and clinical examination was normal. Abdominal CT scan was requested and revealed an apparently retroperitoneal, para-aortic, hypodense, lobulated soft-tissue mass measuring 7.7×3.2 cm and intimately related to the crus of the left hemidiaphragm (figure 1A,B).
(A, B) Abdominal CT scan showing a hypodense soft-tissue mass measuring 7.7×3.2 cm intimately related to the diaphragm in an apparent retroperitoneal location. (C, D) Abdominal MRI showing an apparent retroperitoneal soft-tissue mass with the same characteristics as previously described.
The patient was evaluated by the endocrinological department and biochemical assessment was performed ruling out functional paraganglioma. Tumour markers were also negative. After this, the case was discussed in a multidisciplinary tumour board and a CT-guided core biopsy was performed with a 14G needle using a posterior approach. Histopathological studies of the samples were non-conclusive. Based on this result, the decision was made for complete en-bloc surgical resection. The patient underwent en-bloc resection of the tumour along with partial resection of the left hemidiaphragm and primary closure using non-absorbable interrupted sutures via a laparotomy approach (figure 2A). She was discharged on the sixth postoperative day without complications. Final histopathological examination confirmed a benign intradiaphragmatic BC completely resected. The mass measured 7.5×6×3 cm and was composed of multiple cysts (figure 2B) and mucinous glands coated with ciliated, pseudostratified, columnar respiratory epithelium and cartilage (figure 2C,D).
(A) Surgical lodge after tumour resection previous to the primary closure of the left hemidiaphragm. White arrows point to the diaphragm. L, lung; LHL, left hepatic lobe; S, stomach. (B) Gross macroscopic specimen. (C, D) Histological examination showing multiple cysts coated with pseudostratified, ciliated, columnar epithelium with caliciform cells surrounded by fibroconnective tissue and cartilage (40× and 100× H&E stain).
Differential diagnosis
Due to the impossibility to establish a definitive diagnosis on an imaging basis only of a suspected retroperitoneal mass, pathological assessment remains the gold standard of diagnosis. A percutaneous CT-guided core-needle biopsy was performed using the retroperitoneal approach. This route shows a minimal risk of seeding by preserving the posterior parietal peritoneum.
Treatment
BCs have a good prognosis if complete surgical resection is performed.
Outcome and follow-up
After 6 months of follow-up, the patient has remained asymptomatic without evidence of recurrence.
Discussion
BC is a rare benign tumour originating secondary to a congenital malformation in which an abnormal budding of the early lung before bronchus formation results in a blind-ending, fluid-filled pouch.4 Hence, they are usually found in the lung parenchyma or the mediastinum (especially posterior to the carina) and can be associated with other congenital pulmonary malformations. In addition, they can occur in other locations (ie, neck, retroperitoneum) and are called ectopic BCs.5–7 Ectopic BCs are very uncommon and even rarer than the intradiaphragmatic ones. Diaphragmatic BCs typically occur on the left, in women and in the vertebra-phrenic angle.2 8 9 In a recent report, Tang et al 1 stated that 24 ectopic BCs have been reported in the past 15 years, of which only 3 (including theirs) were diaphragmatic.
Most patients are usually asymptomatic or have non-specific minimal clinical symptoms often directly correlated with the localisation. Moreover, potential complications of BCs such as infection,10 bleeding,5 rupture of the cyst11 and malignant transformation3 have been described, but none of these has ever been reported in an intradiaphragmatic location.
Imaging examination has great value in early detection of BCs, but there are no specific manifestations on CT or MRI scans and are not completely diagnostic. Given their rarity, it is difficult to make diagnosis on imaging alone. Preoperative localisation is sometimes challenging too. In fact it is common to confuse this pathology with another primary organ disease arising in the thoracic or abdominal cavity. In the 2016 Mubang et al 2 review, the presumed diagnosis prior to resection varied quite significantly, but BCs were most commonly confused with adrenal masses. In our case, the images were interpreted as a retroperitoneal tumour intimately related with the diaphragm and the left adrenal gland was normal. During the diagnostic work-up of a retroperitoneal mass, a percutaneous biopsy is of utmost importance to help guide the therapeutic strategy.12 Having discarded the possibility of a functional tumour, we effectively did a percutaneous biopsy using a posterior approach. Despite being not conclusive, this is a procedure with minimal risks and which we think is very important in the decision making of these cases.
Due to the aforementioned, different approaches to resection of postoperatively diagnosed BCs have been used and all of them seem to be appropriate for a successful surgery (including minimally invasive ones). Nevertheless, the most common surgical approach is thoracotomy (47.4%) and the most common diaphragmatic reconstructive method is primary closure (69.2%).2 In our case, on interpreting this tumour as a retroperitoneal tumour without clear diagnosis, laparotomy approach was decided to ensure complete and oncologically secure surgery.
Finally, possible reasons for complete surgical resection in these cases include situations of an unclear diagnosis, potential risks of complications or malignant transformation, and symptomatology if present.
Patient’s perspective
My case was presented and discussed in a Multidisciplinary Tumor Board. I felt very comfortable and secure in the pre-op stage and nowadays during the follow-up. Moreover, I have direct communication with the surgical team in case of any need or doubt.
Learning points
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Diaphragmatic bronchogenic cysts (BCs) are extremely rare congenital tumours and pathological assessment is the only procedure for definitive diagnosis.
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BCs should remain a differential diagnosis of any soft-tissue mass in the region of the diaphragm.
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Complete surgical resection is recommended even in asymptomatic patients.
Ethics statements
Patient consent for publication
Footnotes
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Contributors WSN and SDQ were involved in study concept and design and drafting of the manuscript. WSN, LM and PD were involved in acquisition of data. WSN and SDQ critically revised the manuscript for important intellectual content. SDQ contributed to the final version and final approval for publication. All authors read and approved the final version.
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Funding The authors have not declared a specific grant for this research from any funding agency in the public, commercial or not-for-profit sectors.
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Case reports provide a valuable learning resource for the scientific community and can indicate areas of interest for future research. They should not be used in isolation to guide treatment choices or public health policy.
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Competing interests None declared.
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Provenance and peer review Not commissioned; externally peer reviewed.
- © BMJ Publishing Group Limited 2022. No commercial re-use. See rights and permissions. Published by BMJ.
References
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