Clinical History
An elderly lady, widow for several years, no children or kin, was admitted in a retirement home for the initial symptoms of dementia. During the routine examinations a chest radiograph showed a few anomalies.
Imaging Findings
The frontal chest radiograph showed a large opacity, with a central air-fluid level in the retrocardiac region suggestive of a sliding hiatal hernia and a rounded parenchymal consolidation above the right diaphragm. This parenchymal consolidation was not visible on the lateral chest radiograph.
An unenhanced CT examination was performed for further investigation of the radiographic findings.
This confirmed the large sliding hiatal hernia and showed a rounded mass with a homogeneous fat density in the right posterior lower thorax, caused by herniation of retroperitoneal fat through an interruption of right diaphragmatic musculature. The findings were suggestive of Bochdalek's hernia (BHs).
Discussion
Sliding hiatal hernia is a common finding. This is an acquired condition in which a portion of the stomach protrudes into the chest cavity through the oesophageal hiatus. Much less common is the detection, in adulthood, of Bochdalek's hernia (BH).
This is the most common type of congenital defect of the diaphragm through which the abdominal contents may switch into the chest cavity [1]. The defect results from delay or failure of closure of the embryonic pleuroperitoneal membrane [1-2]. First described by Bochdalek in 1848, BH most frequently arises on the left side but can also be bilateral.
BH may be found in patients of any age, however, normally this condition is diagnosed in neonatal and postnatal patients who present acute symptoms of respiratory distress and cyanosis due to a large herniation of abdominal organs.
The defect of diaphragmatic musculature can vary in size as well as the contents of the herniation. The small size of diaphragmatic defect and the herniation solely of peritoneal fat can be asymptomatic and this condition, undiagnosed in childhood, can be incidentally discovered in adulthood.
The true prevalence of BH is unknown, estimations vary between 0.17% and 6%. Nevertheless, the identification of BH in adults occurs most frequently than before CT era due to the increase of patients undergoing CT examinations for other reasons [3].
Presentation of BH in adults varies, often asymptomatic, some patients can present chest pain, difficulty in breathing, abdominal pain or intestinal obstruction. The diagnosis can be established using various imaging techniques. Chest radiograph is usually the first procedure, showing a soft-tissue opacity or a solitary rounded lesion at the lung base. Other imaging methods such as barium studies, radionuclide imaging and ultrasound may also be useful but are of limited value.
CT examination and especially multislice CT with multiplanar reformatting of the images is the most accurate method of diagnosing and evaluating the diaphragmatic hernias [4].
CT findings are the following: 1) a low-attenuated mass neighbouring the posterior portion of the diaphragm, 2) the discontinuity of the diaphragmatic musculature adjacent to the mass and 3) the continuity of the subdiaphragmatic and supradiaphragmatic densities through the diaphragmatic defect.
Small and asymptomatic BH have poor clinical relevance and require no treatment, however, can create problems of differential diagnosis with several lung diseases [5].
Surgery is the treatment of choice in symptomatic cases.
Differential Diagnosis List
Bochdalek's hernia
Lung or pleural neoplasm
Diaphragmatic lipoma
