Riedel lobe is a common anatomical variant of the liver to be aware of because it can simulate a mass. Its misidentification as a pathologic abdominal mass has led to surgery. Pathology can also occur within it (e.g. malignancy or even torsion) and cause atypical hepatic symptoms low in the pelvis 1,2.
Some feel that the term Riedel lobe should be abandoned as it is not an accessory lobe but just a variant of the appearance of the right lobe.
Riedel lobe has an incidence of ~17.5% (range 3.3-31%) and is more frequently found in females (M:F = 1:3) 2,3.
Riedel lobe is a tongue-like, inferior projection of the right lobe of the liver beyond the level of the most inferior costal cartilage on cross-sectional images 1. It is not considered a true accessory lobe of the liver but an anatomical variant of the right lobe of the liver 3.
History and etymology
It was originally reported in 1888 by the German surgeon, Bernhard Moritz Carl Ludwig Riedel (1849-1916) 4 in seven female patients who had palpable masses in the right hypochondrium, which were subsequently confirmed at surgery 2.
- 1. Kudo M. Riedel's lobe of the liver and its clinical implication. Intern. Med. 2000;39 (2): 87-8. Intern. Med. (link) - Pubmed citation
- 2. Gillard JH, Patel MC, Abrahams PH, et al. Riedel's lobe of the liver: fact or fiction? Clin Anat 1998; 11(1):47-9.
- 3. Yano K, Ohtsubo M, Mizota T et-al. Riedel's lobe of the liver evaluated by multiple imaging modalities. Intern. Med. 2000;39 (2): 136-8. Pubmed citation
- 4. Anton Sebastian. A Dictionary of the History of Medicine. (1999) ISBN: 9781850700210