Schwannoma

Colon tumor
Mesenchymal tumors
Schwannoma

Author: Charanjeet Singh, M.D. (see Authors page)

Revised: 4 January 2017, last major update May 2012

Copyright: (c) 2003-2017, PathologyOutlines.com, Inc.

PubMed search: colonic schwannoma

Table of Contents

Cite this page: Schwannoma. PathologyOutlines.com website. http://www.pathologyoutlines.com/topic/colontumorschwannoma.html. Accessed July 14th, 2017.

Definition / general

Rare; less common than colonic GIST
Median age 65 years, range 18 - 87 years; affects men and women equally
Benign behavior; not associated with neurofibromatosis

Case reports

52 year old man with neurofribromatosis causing intussusception (Thomas Jefferson University 2006)
68 year old woman with sigmoid tumor (Kurume Med J 2000;47:165)
70 year old man with rectal tumor with synchronous colonic adenocarcinoma (World J Surg Oncol 2005;3:46)
72 year old man and 54 year old man with plexiform schwannoma (Mod Pathol 1997;10:1075)
2 cases - 73 year old woman and 44 year old man with submucosal tumor (Surg Today 2001;31:833)

Clinical images

Images hosted on other servers:

Submucosal colonic tumors

Gross description

Well circumscribed but usually not encapsulated, polypoid intraluminal mass 0.5 to 5.5 cm with mucosal ulceration, usually in right colon

Gross images

Images hosted on other servers:

Various images

Microscopic (histologic) description

In soft tissue, encapsulated biphasic nerve sheath tumor derived from Schwann cells with highly ordered cellular component (Antoni A) that palisades (Verocay bodies), plus myxoid component (Antoni B)
In colon, usually no encapsulated, no / indistinct Verocay bodies, no prominent nuclear palisading (Am J Surg Pathol 2001;25:846)
Usually trabecular pattern of spindle cells, surrounded by lymphoid cuff
May have epithelioid or plexiform features
Often focal nuclear atypia; 0 - 4 mitotic figures / 50 HPF
Usually no vascular hyalinization, no xanthoma cells

Microscopic (histologic) images

Images hosted on other servers:

Various images

Various immunostains

Positive stains

S100, GFAP
May have PAS+ needle shaped crystalloids (Am J Surg Pathol 1999;23:431)
Also type IV collagen, low affinity nerve growth factor receptor (p75)

Negative stains

CD117 / c-kit, smooth muscle actin, desmin, CD34 (usually) and Ki67 (less than 3%)

Differential diagnosis

GIST: CD117+, CD34+, S100-, no prominent lymphoid infiltration and no microtrabecular pattern
Inflammatory myofibroblastic tumor: spindle cells with abundant amphophilic cytoplasm
Leiomyoma: rare, usually small polyps and positive for smooth muscle markers