Intranodal Palisaded Myofibroblastoma
Definition
- Intranodal mass with prominent palisading and amianthoid fibers
Alternate/Historical Names
- Intranodal hemorrhagic spindle cell tumor with amianthoid fibers
- Solitary spindle cell tumor with myoid differentiation of the lymph node
Note: the following are related in name only
- Mammary Type Myofibroblastoma is a circumscribed soft tissue tumor frequently containing fat, lacking Rb expression
- Intranodal Palisaded Myofibroblastoma is an intranodal tumor with increased beta-catenin expression
- Superficial Myofibroblastoma is a superficial lesion that is that does not involve fat and is restricted to the external female reproductive tract
Diagnostic Features
- Nearly always inguinal node
- Intranodal circumscribed nodule
- Usually solitary
- Thin pseudocapsule
- Bland spindle cells with prominent palisading
- Infrequent mitoses
- Eosinophilic collagenous (“amianthoid”) bodies
- Stellate and cylindrical
- Central hyalinization, may calcify
- Eosinophilic perinuclear inclusion bodies
- Trichrome red
- Hemorrhage and hemosiderin frequent
- Smooth muscle actin and muscle specific actin positive
- Nuclear beta-catenin and cyclin D1 positive
- Desmin infrequent
- S100, CD34 negative
- Benign, recurrence extremely rare
Bibliography
- Agaimy A, Haller F. CTNNB1 (β-Catenin)-altered Neoplasia: A Review Focusing on Soft Tissue Neoplasms and Parenchymal Lesions of Uncertain Histogenesis. Adv Anat Pathol. 2016 Jan;23(1):1-12. PubMed PMID: 26645457.
- Laskin WB, Lasota JP, Fetsch JF, Felisiak-Golabek A, Wang ZF, Miettinen M. Intranodal palisaded myofibroblastoma: another mesenchymal neoplasm with CTNNB1 (β-catenin gene) mutations: clinicopathologic, immunohistochemical, and molecular genetic study of 18 cases. Am J Surg Pathol. 2015 Feb;39(2):197-205.. PubMed PMID: 25025452; PubMed Central PMCID: PMC4293230.
Robert V Rouse MD
Department of Pathology
Stanford University School of Medicine
Stanford CA 94305-5342
Original posting 3/14/16
