The Pyloric Sphincteric Cylinder in Health and Disease

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Chapter 25 (page 120)

Aron et al. (l973) described the case of an elderly female in whom radiographic examination showed an hiatus hernia and a large filling defect on the lesser curvature side of the "distal antrum" with narrowing of the antral outlet. Endoscopy revealed oesophagitis while an irregular submucosal lesion measuring 2.5 cm x 0.5 cm was seen approximately l.0 to 2.0 cm proximal to the pylorus on the lesser curvature side; biopsy showed a normal mucosa. At operation a localized, firm, nodular mass measuring 3.0 cm in length and extending from the pylorus to the "distal antrum" on the lesser curvature, was found. Histology revealed marked hypertrophy of the circular musculature, diagnosed as torus hyperplasia which had presented as a gastric pseudotumor.

Liebermann-Meffert and Allgöwer (l977) investigated the morphology of the pylorus and "antrum" in gastric ulcer disease. In a series of 77 cases the ulcer was adjacent to the pylorus in 10, and in other parts of the stomach in 67. Focal areas of muscle hypertrophy which distorted either the "antrum", the pyloric ring or both were commonly found. The hypertrophy was not uniform but irregular, involving different parts of the pylorus and "antrum" to a variable degree. The findings were not described in detail nor interpreted in the light of the anatomy as determined by Cunningham (1906), Forssell (1913) and Torgersen (1942).


At least 27 cases of focal hypertrophy (including one of focal spasm) of the pyloric musculature in adults have been described in detail in the literature. Seventeen were not associated with other lesions in the upper gastrointestinal tract and apparently occurred de novo. Four cases were associated with chronic or atrophic gastritis (one also had achylia gastrica), one with an acute erosion, 2 with hiatus hernia, 2 with gastric and one with duodenal ulceration.

In 17 cases the hypertrophy (or spasm in one case) was limited to the pyloric muscle torus or knot. (The l7 cases in this group do not tally with the l7 mentioned above). Normally contraction of the pyloric muscle knot is a fleeting occurrence, being part of cyclical contraction of the sphincteric cylinder; it causes an evanescent widening of the lesser curvature part of the pyloric ring (Chap. 13). In focal hypertrophy of the muscle knot the mass occurs in the same situation and is permanent. The condition may be considered to be the pathological counterpart of a physiological stage of contraction.

Radiographically Seaman (l966) noted a permanent widening of the lesser curvature side of the pyloric ring in 2 of his 4 cases of torus hyperplasia. In retrospect this was also present in our Case 25.1. A similar but very advanced case was described by Aron et al. (l973). Torus hyperplasia should be considered in the radiological differential diagnosis of permanent widening of the lesser curvature side of the pyloric ring.

In 7 of the remaining l0 cases (described by Bachmann) the focal hypertrophy, while not strictly limited to the muscle torus, occurred in the same region and can probably be explained on the same basis. In 3 the hypertrophy occurred elsewhere in the pyloric musculature; this also applied to the cases of Liebermann-Meffert and Allgöwer (l977), which were not described individually.

It is concluded that focal hypertrophy is limited to the pyloric muscle torus in many instances, but this is not invariably the case and it may also occur elsewhere in the pyloric musculature. It may occur de novo or be associated with gastric ulceration (located more proximally in the stomach), chronic or erosive gastritis, hiatus hernia and duodenal ulceration. Whether it represents an early stage of diffuse adult hypertrophic pyloric stenosis is not known.


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  2. Bachmann KD. Über umschriebene, plattenförmige Muskelhyperplasien im Antrum und Pylorus ("Muskelplatten"), Beitr path Anat l952, 112, 97 - 103.
  3. Cunningham DJ. The varying form of the stomach in man and the anthropoid ape. Trans Roy Soc Edin l906, 45, 9 - 47.
  4. Forssell G. Über die Beziehung der Röntgenbilder des menschlichen Magens zu seinem anatomischen Bau. Fortschr Geb Röntgenstr 1913, Suppl 30, 1 - 265.
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  7. Knight CD. Hypertrophic pyloric stenosis in the adult. Ann Surg l96l, 153, 899 - 910.
  8. Liebermann-Meffert D, Allgöwer M. The morphology of the antrum and pylorus in gastric ulcer disease. Prog Surg 1977, 15, 109 - 139.
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  10. Seaman WB. Hypertrophy of the pyloric muscle in adults. Radiology l963, 80, 753 - 764.
  11. Seaman WB. Focal hypertrophy of the pyloric muscle: torus hyperplasia. Amer J Roentg Rad Ther Nucl Med l966, 96, 388 - 392.
  12. Skoryna SC, Dolan HS, Gley A. Development of primary pyloric hypertrophy in adults in relation to the structure and function of the pyloric canal. Surg Gynaec Obstet l959, 108, 83 - 92.
  13. Torgersen J. The muscular build and movements of the stomach and duodenal bulb. Acta Rad l942, Suppl 45, 1 - 191.
  14. Wellman KF, Kagan A, Fang H. Hypertrophic pyloric stenosis in adults: survey of the literature and report of a case of the localized form (torus hyperplasia). Gastroenterology l964, 46, 601 - 608.

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