Soft tissue

Fibroblastic / myofibroblastic

Intranodal palisaded myofibroblastoma

Last author update: 1 April 2013
Last staff update: 23 June 2021

Copyright: 2002-2023,, Inc.

PubMed Search: Intranodal palisaded myofibroblastoma

Lauren N. Stuart, M.D., M.B.A.
Jerad M. Gardner, M.D.
Page views in 2022: 3,596
Page views in 2023 to date: 1,872
Cite this page: Stuart L. Intranodal palisaded myofibroblastoma . website. Accessed June 9th, 2023.
Definition / general
  • Benign lymph node tumor composed of myoid or myofibroblastic spindle cells, with focal palisading and so-called "amianthoid" fibers
  • Distinctly resembles schwannoma
  • Also called intranodal hemorrhagic spindle cell tumor with amianthoid fibers
  • Formerly called intranodal schwannoma
  • Amianthoid: resembles amianthus, a type of asbestos with particularly fine fibers (see images below); although tumor fibers resemble amianthoid fibers, they are actually composed of normal thickness collagen rather than the thick collagen fibers comprising "true" amianthoid fibers (Arch Pathol Lab Med 2007;131:306)
  • Initially described by Weiss et al (Am J Surg Pathol 1989;13:341) and Suster et al (Am J Surg Pathol 1989;13:347)

Images hosted on other servers:


Clinical features
Prognostic factors
Case reports
  • Local excision is almost always curative
Gross description
  • Well circumscribed, gray-white with hemorrhage and peripheral nodal tissue
Microscopic (histologic) description
5 key features:
  • Spindle cell proliferation surrounded by hemorrhage and collagenous pseudocapsule; growing nodule compresses remaining nodal tissue
  • Bland spindle cells with areas of nuclear palisading
  • Intraparenchymal hemorrhage and red blood cell extravasation
  • So-called amianthoid fibers
  • Extra- and intracellular fuchsinophilic bodies (best seen with SMA stain, Arch Pathol Lab Med 2007;131:306)
Microscopic (histologic) images

Images hosted on other servers:

Various images

Amianthoid fibers composed of a
central vessel surrounded by a core
of collagen with peripheral spokes,
strongly stained by Van Gieson (elastin)

Cytology description
  • Moderately cellular with benign appearing, dissociated, single spindle cells with elongated nuclei, pointed ends and occasional twisted forms
  • In pale fibrillary matrix with hemosiderin granules, no atypia (Acta Cytol 2002;46:1143)
Positive stains
Negative stains
Electron microscopy description
  • Rough endoplasmic reticulum cisternae
  • Some smooth-muscle type myofilaments
  • Subplasmalemmal densities, plasmalemmal caveolae, and external lamina at cell surface
  • Lacks the fibronexus junctions typical of myofibroblasts
  • So-called "amianthoid fibers" are actually collagen fibrils with typical diameter of 50 - 83 nm, compared to giant collagen fibrils typical of true amianthoid (Ultrastruct Pathol 1996;20:79)
Differential diagnosis
  • Benign metastasizing leiomyoma: smooth muscle cells are more ovoid with more prominent eosinophilic cytoplasm, no hemorrhage, no amianthoid fibers, usually metastasizes to lung
  • Follicular dendritic cell sarcoma: nests or whorls of plump cells with scattered inflammatory cells, no prominent hemorrhage, no amianthoid fibers, CD21+, CD35+
  • Kaposi sarcoma: curved fascicles of spindle cells with atypia and PAS+ hyaline globules, brisk mitotic activity, slit-like vessels with extravasated red blood cells, scattered plasma cells in infiltrate, no amianthoid fibers; HHV8+, FLI1+, CD34+, CD31+
  • Sarcoma (metastatic to lymph node): more atypical and more mitotically active, most sarcomas do not present initially with lymph node metastases (although nodal metastasis may develop in patients with disseminated disease)
  • Schwannoma: often biphasic, no amianthoid fibers, not nodal, S100+
  • Spindle cell carcinoma (metastatic to lymph node): more atypical and more mitotically active, often keratin+, p63+
  • Spindle cell melanoma (metastatic to lymph node): more atypical and more mitotically active, S100+
Back to top
Image 01 Image 02