TY - JOUR
T1 - Colonic Adventitial Fibromuscular Dysplasia
T2 - A Nonspecific Arteriopathy Associated With Hirschsprung Disease and Other Obstructive Disorders
AU - Thaker, Ameet I.
AU - Kapur, Raj P.
N1 - Funding Information:
The author(s) disclosed receipt of the following financial support for the research, authorship, and/or publication of this article: The study was partially supported by a Seattle Children’s Hospital Academic Enrichment Fund Award (RPK).
Publisher Copyright:
© 2017, Society for Pediatric Pathology All rights reserved.
PY - 2018/7/1
Y1 - 2018/7/1
N2 - Background: Smooth muscle differentiation (“adventitial fibromuscular dysplasia,” AFD) was purported as specific to arteries in the transition zone of Hirschsprung disease (HSCR) patients. We investigated AFD in an HSCR population and controls and consider the pathogenesis and significance of the vascular pathology. Design: Vascular histology in sections from colonic HSCR resections (n = 55) was compared with age- and site-matched controls with (n = 19) and without (n = 28) non-HSCR obstructive conditions. Vascular pathology was mapped, and correlations were sought between the vascular findings and bowel distension, inflammation, neuromuscular anatomy, preoperative clinical variables, and postsurgical complications. Results: One of 2 forms of AFD was identified in 42% (23/55) of the HSCR resections: the previously described “mature” form with adventitial bundles of differentiated smooth muscle cells (7/23, all submucosal) and a newly described “immature” AFD characterized by densely packed myofibroblasts in the arterial adventitia (16/23, 3 submucosal, 3 serosal, and 10 both). Adventitial inflammation and/or medial necrosis was present in the immature form (6/16). Mature submucosal AFD was present in 2/28 (7.1%) nonobstructive and 5/19 (26%) obstructive non-HSCR controls (P =.10). Immature AFD was only found in less than 1-month-olds, and mature AFD only in older patients, including the 7 affected controls. AFD did not correlate with sex, syndromic status, length of the aganglionic segment, or postoperative complications. AFD was present in grossly dilated (17/23) and narrowed (10/23) regions and in the aganglionic (2/23), ganglionic (14/23), or both (7/23) segments. In several cases, AFD existed proximal to the histological transition zone. Conclusion: AFD occurs in HSCR and other obstructive conditions but is significantly less common in the colons of patients with no history of dysmotility. The pathology likely progresses from a reversible accumulation of myofibroblasts in neonates to a stable population of mature smooth muscle cells. The distribution of vascular lesions does not correlate with neuropathological findings and suggests a nonspecific form of vascular injury, possibly related to bowel distension. AFD in HSCR resections has not been shown to be clinically significant and should not influence management.
AB - Background: Smooth muscle differentiation (“adventitial fibromuscular dysplasia,” AFD) was purported as specific to arteries in the transition zone of Hirschsprung disease (HSCR) patients. We investigated AFD in an HSCR population and controls and consider the pathogenesis and significance of the vascular pathology. Design: Vascular histology in sections from colonic HSCR resections (n = 55) was compared with age- and site-matched controls with (n = 19) and without (n = 28) non-HSCR obstructive conditions. Vascular pathology was mapped, and correlations were sought between the vascular findings and bowel distension, inflammation, neuromuscular anatomy, preoperative clinical variables, and postsurgical complications. Results: One of 2 forms of AFD was identified in 42% (23/55) of the HSCR resections: the previously described “mature” form with adventitial bundles of differentiated smooth muscle cells (7/23, all submucosal) and a newly described “immature” AFD characterized by densely packed myofibroblasts in the arterial adventitia (16/23, 3 submucosal, 3 serosal, and 10 both). Adventitial inflammation and/or medial necrosis was present in the immature form (6/16). Mature submucosal AFD was present in 2/28 (7.1%) nonobstructive and 5/19 (26%) obstructive non-HSCR controls (P =.10). Immature AFD was only found in less than 1-month-olds, and mature AFD only in older patients, including the 7 affected controls. AFD did not correlate with sex, syndromic status, length of the aganglionic segment, or postoperative complications. AFD was present in grossly dilated (17/23) and narrowed (10/23) regions and in the aganglionic (2/23), ganglionic (14/23), or both (7/23) segments. In several cases, AFD existed proximal to the histological transition zone. Conclusion: AFD occurs in HSCR and other obstructive conditions but is significantly less common in the colons of patients with no history of dysmotility. The pathology likely progresses from a reversible accumulation of myofibroblasts in neonates to a stable population of mature smooth muscle cells. The distribution of vascular lesions does not correlate with neuropathological findings and suggests a nonspecific form of vascular injury, possibly related to bowel distension. AFD in HSCR resections has not been shown to be clinically significant and should not influence management.
KW - Hirschsprung
KW - adventitia
KW - artery
KW - colon
KW - fibromuscular
KW - vascular
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U2 - 10.1177/1093526617739772
DO - 10.1177/1093526617739772
M3 - Article
C2 - 29108502
AN - SCOPUS:85050192892
SN - 1093-5266
VL - 21
SP - 363
EP - 370
JO - Pediatric and Developmental Pathology
JF - Pediatric and Developmental Pathology
IS - 4
ER -