Simultaneous degeneration of myenteric plexuses and pelvic parasympathetic colonic nerve in slow transit constipation: A case report

Abstract

Rationale: Slow transit constipation (STC) is a common disease of which the etiology is still not clear. Multiple hypotheses have been proposed to explain STC, including autonomic neuropathy, disorders of the enteric nervous system and so forth. Morphological abnormalities of the enteric nerves of the colon in patients with STC have been extensively reported, while there have been no morphological reports focusing on extrinsic extramural fibers from the pelvic plexus to the distal colon (i.e., pelvic parasympathetic colonic nerve) in patients with STC.

Patient concerns: Whether morphological changes of pelvic parasympathetic colonic nerve coexist with abnormalities of the enteric nerves of the colon in the patient with STC.

Diagnosis: Slow transit constipation (STC).

Interventions: The patient with STC underwent a partial colectomy (sigmoid colon and partial descending colon). The fibers of the myenteric plexuses within the removed colon and the myelinated fibers of the pelvic parasympathetic colonic nerve were observed under optical and electron-microscope.

Outcomes: The fibers of the myenteric plexuses showed vacuolated degeneration between the muscularis propria layer under optical microscope. Myelinated fibers of the pelvic parasympathetic colonic nerve showed obvious vacuolated degeneration under electron-microscopic examination.

Lessons: Such a simultaneous neuropathy in both myenteric plexuses and extrinsic extramural nerves has not been documented previously. Our finding supports the notion that neuropathy remains the most plausible explanation for STC, in which nerve dysfunction might occur by way of a degenerative process.

Figure 1

Nerve samples were taken from the pelvic parasympathetic colonic nerve. PPCN = pelvic parasympathetic colonic nerve, SHP = superior hypogastric plexus.

Figure 2

Vacuolated degenerated nerve fibers are diffusely scattered throughout the muscularis propria layer. A, HE stain, ×100. B, HE stain, ×400.

Figure 3

A, Vacuolated areas (V) frequently observed within the myelinated axon (M) and the cytoplasm of the Schwann cells. B, Vacuolated areas (V) external to the Schwann cells (×10,000; bar = 500 nm).