We report herein a case of Morgagni hernia of epiploon into the pleural space.

We report herein a case of Morgagni hernia of epiploon into the pleural space, simulating a pleural effusion forward a routine chest radiograph. A 62-year-old man was referr to our clinic for complete examination of a pleural effusion-like shadow at the right costophrenic region. He had no history of trauma and no symptoms. Chest comput tomographic scan showed a pleural effusion-like shadow with a fat density. Thoracoscopy revealed a movable omentum-like mass and no significant fluid in the right pleural space. Magnetic resonance imaging and celiac angiography confirmed the herniation of epiploon into the right pleural space. This case hints that a Morgagni hernia must be exclud in a patient with a fat density effusion-like shadow in the pleural space. (Chest 1994; 106:285-87)

Herniation of caul through the formation of Morgagni is rare and exhibits only 3 percent of diaphragmatic hernias.(1) Patients with hernia of Morgagni are usually asymptomatic and ready with right cardiophrenic angle opacification forward routine chest radiograph, since a hernia sac contains colon or omentum(2)(3)(4)(5) We report herein a case of caul herniation through the foramen of Morgagni into the right pleural space, simulating effusion upon a routine chest radiograph.

CASE REPORT

A 62-year-old man had spontaneous right upper abdominal pain and thereafter abdominal discomfort; he was believed to have a gallstone in 1988 In another hospital, he had received various examinations, including a chest radiograph that failed to find a definitive cause. A year later, in 1989 an abnormal shadow appeared in the right costophrenic region forward a routine chest radiograph. Various examinations failed to find its cause. A thoracentesis was attempted, yet no fluid could be obtained. For pleural effusion of unknown origin, however, he received diuretics and glucocorticoids (prednisolone, 40 to 10 mg/d for 1 month) The treatment with these physics did not produce any significant alterations in the apparent pleural effusion in the chest radiograph, although the shadow did change independently of any treatments.

In April 1991 he was referr to our clinic for a choke examination of the pleural effusion-like shadow (Fig 1) He was 168 cm tall, weighed 70 kg and had no history of prior trauma. Findings from all routine laboratory and pulmonary function studies were normal. A chest radiograph disclosed a pleural effusion-like shadow at the right costophrenic region that changed its shape depending onward body position as shown in Figure 1 We tried however failed to obtain pleural fluid from a thoracentesis.

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A chest comput tomographic (CT) scan also exhibited a pleural effusion-like shadow with a fat density; the tail portion of the density coursed toward the anteromedial aspect of the diaphragm. A secondary CT examination showed that intravenously administered contrast medium enhanced the CT images of the lesion. Magnetic resonance imaging showed that the signal intensity of the lesion was comparable to that of subcutaneous fat, and the coronal and sagittal images showed the lesion to be an extension of fatty tissue in consequence of an anteromedial portion of diaphragm from abdominal fat tissue.

Thoracoscopy was performed to determine the nature of the lesion and revealed the personality of movable fat tissue (approximately 17x5x2 cm) with small utensils on the surface (omentum-like) in the right pleura space, with a neck (approximately 3x3 cm) to the anteromedial portion of diaphragma. Macroscopically, this tissue was clearly different from lipoma or neoplasm. No significant fluid was place in the pleural space. The biopsy specimen subordinate to thoracoscopy showed histologicaly normal fat tissue.

A barium enema failed to indicate a definite diaphragmatic herniation of colon Angiography of the celiac artery was performed to confirm the port of omentum in the pleural space. It revealed that a branch of gastroepiploic artery enrolled into the shadow in the right lung field, as shown in Figure 2 Although surgery was commended to prevent strangulation of the omentum(6) the patient refused to bear surgery.

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DISCUSSION

Morgagni hernia consists of a protrusion of abdominal peaces (omentum and/or transverse colon) with the hernia sac into the thorax in consequence of an anteromedial defect in the diaphragm. Patients with Morgagni hernia are usually asymptomatic and evaluated following an abnormal shadow of mass lesion that bear likeness [i]or[/i] resemblance tos mediastinal tumor, pericardial cyst, lung tumor, or abscess.(1)(2)(3)(4)(5) Diaphragmatic hernia is infrequently accompanied by means of pleural effusion(7) but in our case there were no findings indicative of pleural effusion. To our best knowledge, however, there have been no reports of patients with the protrusion of caul into the pleural space resembling effusion forward a routine chest radiograph. Since hernia is defined as protrusion with hernia sac, this case may not actually delineate "hernia." However, we cannot find any adequate spells for the present case and we used "Morgagni hernia" in this report.

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