Colonic Pseudo-obstruction With Transition Zone: A Peculiar Eastern Severe Dysmotility

Abstract

Background/aims: Previous studies from Korea have described chronic intestinal pseudo-obstruction (CIPO) patients with transition zone (TZ) in the colon. In this study, we evaluated the pathological characteristics and their association with long-term outcomes in Korean colonic pseudo-obstruction (CPO) patients with TZ.

Methods: We enrolled 39 CPO patients who were refractory to medical treatment and underwent colectomy between November 1989 and April 2016 (median age at symptoms onset: 45 [interquartile range, 29-57] years, males 46.2%). The TZ was defined as a colonic segment connecting a proximally dilated and distally non-dilated segment. Detailed pathologic analysis was performed.

Results: Among the 39 patients, 37 (94.9%) presented with TZ and 2 (5.1%) showed no definitive TZ. Median ganglion cell density in the TZ adjusted for the colonic circumference was significantly decreased compared to that in proximal dilated and distal non-dilated segments in TZ (+) patients (9.2 vs 254.3 and 150.5, P ＜ 0.001). Among the TZ (+) patients, 6 showed additional pathologic findings including eosinophilic ganglionitis (n = 2), ulcers with combined cytomegalovirus infection (n = 2), diffuse ischemic changes (n = 1), and heterotropic myenteric plexus (n = 1). During follow-up (median, 61 months), 32 (82.1%) TZ (+) patients recovered without symptom recurrence after surgery. The presence of pathological features other than hypoganglionosis was an independent predictor of symptom recurrence after surgery (P = 0.046).

Conclusions: Hypoganglionosis can be identified in the TZ of most Korean CPO patients. Detection of other pathological features in addition to TZ-associated hypoganglionosis was associated with poor post-operative outcomes.

Keywords: Colonic pseudo-obstruction; Intestinal pseudo-obstruction; Outcomes; Pathology.

Figure 1

Ganglion cell count (A) and ganglion cell density (B) differences between the transition zone (TZ) and other colonic segment. The median value of each groups are presented. *Ganglion cell count/cm × internal circumference (cm). PD, proximal dilated; DN, distal non-dilated.

Figure 2

Pathologic characteristics of typical hypoganglionosis with transition zone (TZ) (patient No. 13). (A) Gross photograph shows markedly dilated proximal colonic segments, non-dilated distal segments, and TZ connecting them (arrow). Dashed line indicates hypoganglionic segment. (B) Myenteric plexus of the proximal dilated segment shows abundant ganglion cells and Schwann cells (×40 objective lens, scale bar = 50 μm). (C) Myenteric plexus in TZ shows atrophic Schwann cells without ganglion cells or inflammation (×40 objective lens, scale = 50 μm). (D) Schematic view of a novel pathologic analysis. In this particular case, sections were taken every 5-cm (intervals of vertical lines of upper panel). Numbers of ganglion cells are markedly decreased especially in the distal TZ and the decrease in ganglion cells is observed for a certain length (approximately 10 cm in this case) after TZ. Then, the number of ganglion cells recovers thereafter. The recovered ganglion cell numbers are seemingly larger than those of proximal dilated segment, but both become similar when the internal circumference (IC) is taken into account (lower panel).

Figure 3

Representative photomicrographs for segmental hypoganglionosis cases with other specific features. (A, B) A segmental hypoganglionosis case with eosinophilic ganglionitis (patient No. 24). Colonic segment distal to the transition zone shows reddish discoloration (arrow) (A). Several eosinophils are observed along the hypoganglionic myenteric plexus (arrow) (B) (H&E, ×20 objective lens, scale bar = 100 μm). (C, D) A segmental hypoganglionosis case with cytomegalovirus (CMV) infection (patient No. 16). Several geographic ulcers (arrow) are observed in distal ganglionated segment (arrow) (C). CMV immunostaining reveals several CMV inclusions (brown dots) (D) (CMV immunohistochemistry, ×20 objective lens, scale bar = 100 μm). (E, F) A segmental hypoganglionosis case with ischemia (patient No. 12). Proximal dilated segment shows reddish mucosal discoloration and loss of semilunar folds (E). Transmural ischemic changes are seen (F) (H&E, ×4 objective lens, scale bar = 500 μm). (G, H) An intestinal pseudo-obstruction case with transition zone without hypoganglionosis (patient No. 38). Marked dilatation of proximal colon with prominent transition zone (G). Heterotopic ganglions are observed in outer longitudinal muscle layer (arrows) (H) (H&E, ×4 objective lens, scale bar = 500 μm).

Figure 4

Microscopic appearance of colonic pseudo-obstruction without transition zone. (A, B) Diffuse hypoganglionosis with ischemia (patient No. 37). Transmural ischemic necrosis is seen (A) (H&E, ×4 objective lens, scale bar = 500 μm). Note that ganglion cell is absent in the myenteric plexus (arrow) (B) (hematoxylin and eosin [H&E], ×400 objective lens, scale bar = 50 μm), (C, D) Myopathic changes without hypoganglionosis (patient No. 39). Proper muscle layer shows severe loss of smooth muscle fibers and marked interstitial fibrosis (C) (Masson’s Trichrome, ×10 objective lens, scale bar = 200 μm). Ganglion cells are present in the myenteric plexus (arrow) (D) (H&E, ×20 objective lens, scale bar = 100 μm).