CASE STUDY • The Role of Ultrasound in the Diagnosis of Grynfeltt–Lesshaft Lumbar Hernia

INTRODUCTION

Primary lumbar hernia, which was first reported in 1731, is very rare, with about 300 cases reported in the literature to-date. Therefore, lumbar hernias have been often misdiagnosed and lead to delayed detection and delayed treatment. They tend to grow over time and start to present symptoms. If undiagnosed or untreated lumbar hernias could result in death because of the high risk of complications. All lumbar hernias are suggested to be surgically corrected to avoid complications as soon as they are confirmed.

CASE REPORT

A 47-year-old female patient was referred by her family doctor due to a 50 mm swelling at the left flank below the rib cage for 2 months. She had no history of trauma or surgery in her back. No other hernias. On physical examination, there was no visible lump in her left flank when she was sitting or standing.

After the patient was examined in different positions, the swelling finally became evident when the patient was in erect position and bent forwards with both hands on the scanning bed doing a Valsalva maneuver. In this position with the Valsalva maneuver, a subtle swelling approximately 50 mm in size was visible in her left posterior abdominal wall below the rib cage. It was soft with a smooth border. No pain was induced by palpation.

Real-time dynamic US in this region showed that at rest there was only focal fat thickening in the region of latissimus dorsi muscle, and the underlying abdominal wall was intact. With Valsalva maneuver, there was a 14-mm wide defect detected in the posterior abdominal wall muscle with deep soft tissue (fat) protruding through the defect. The diagnosis of a Grynfeltt–Lesshaft hernia was made.

Based on the US findings, a subsequent non contrast CT scans was requested by the surgeon for left lumbar hernia characterization. On the initial resting CT scan, there was asymmetrical thickening of the fat plane between the latissimus dorsi and the transversalis fascia in the overlying latissimus dorsi muscle. With Valsalva maneuver, the underlying fat could be seen extending through a defect in the transversalis fascia measuring approximately 9 mm. The hernia then bulged to a size of 46 x 44 x 17 mm. The hernia contained only fat with no evidence to suggest GI tract or renal involvement.

DISCUSSION & CONCLUSIONS

Lumbar hernias are classified as superior and inferior lumbar hernia based on the location of the defect. Hernia in the superior lumbar triangle is also named Grynfeltt–Lesshaft hernia. The superior lumbar triangle is formed by the quadratus lumborum (medial border), the internal abdominal oblique muscle (lateral border) and the 12^th rib (superior border). Contents of the lumbar hernias may include retroperitoneal fat, colon, small bowel, or kidney.

The most common clinical presentation is swelling in the lumbar area that increases with Valsalva maneuver and disappears in prone position. Clinically, it is difficult to diagnose a lumbar hernia because of its non-specific features. Often when a patient presents with a back lump, the first diagnosis is a lipoma or other common pathology, not a lumbar hernia. Lumber hernias that were misdiagnosed as lipomas have been frequently reported in the past.

The authors concluded that lumbar hernias have been frequently misdiagnosed as lipomas or other pathologies due to its rarity, and that lumbar hernia should be included in the differential diagnosis whenever a patient presents with a lump in the back with or without other symptoms.

They believe that ultrasound can be a useful tool in the diagnosis of lumbar hernia, although more detailed anatomical defects and hernia origins may be better demonstrated on CT.