Home Chapter Home Jobs Conferences Fellowships Books
Breast-malignant, males, children
Low grade myofibroblastic sarcoma
Author: Nat Pernick, M.D, PathologyOutlines.com, Inc.
Reviewer: Daniel Visscher, M.D., University of Michigan Hospitals, February 2009 (see Reviewers page)
Revised: 1 October 2009
Last major update: October 2009
Copyright: (c) 2002-2009, PathologyOutlines.com, Inc.
Definition
=========================================================================
● Rare malignant tumor of myofibroblasts
Terminology
=========================================================================
● Also called myofibrosarcoma
● Not part of WHO breast classification
Clinical
=========================================================================
● Commonly recurs, only rarely metastasizes
Case reports
=========================================================================
● 55 year old woman with death due to metastatic tumor (AJSP 1997;21:489)
Gross
=========================================================================
● Firm, pale, fibrous cut surface, ill defined margins
Microscopic description
=========================================================================
● Fascicles of spindle cells surrounded by dense collagen
● Cells have ill defined, pale, eosinophilic cytoplasm, fusiform and pleomorphic nuclei, numerous mitotic figures
● Also some giant cells
● Margins are infiltrative, often grossly (Pathol Res Pract 1999;195:1)
Micro images
=========================================================================
Fig 1A: fascicular growth
Fig 1B: alpha smooth muscle actin+, vimentin+ (insert)
Fig 1C: fibronectin+ matrix
Fig 1D: type IV collagen negative
Positive stains
=========================================================================
● At least one myogenic marker (desmin, alpha smooth muscle actin, muscle specific actin or calponin)
Negative stains
=========================================================================
● S100, EMA, h-caldesmon, ALK
Electron microscopy
=========================================================================
● Features of myofibroblasts: discontinuous basal lamina, abundant rough endoplasmic reticulum, intermediate filaments and myofilaments; indented and clefted nuclei
EM images
=========================================================================
Fig 2A: arrows point to thin filaments at the cell surface suggestive of fibronexus junctions
Fig 2B: arrows point to fibronectin fibrils extending into the extracellular matrix
Molecular
=========================================================================
● Gains at 1p11-->p36.3 (66%), 12p12.2-->p13.2 (45%), 5p13.2-->p15.3 (31%), +22 (28%), loss at 15q25-->q26.2 (24%) (Am J Clin Pathol 2009;131:701)
Differential diagnosis
=========================================================================
● Leiomyosarcoma - alternating fascicular pattern, usually high grade
● Fibromatosis / myofibromatosis
● Fibrosarcoma
● Inflammatory myofibroblastic tumor - more heterogeneous, less cellular, less hyperchromasia, less infiltrative, ALK+ (Hum Pathol 2008;39:846)
● Myofibroblastoma - may be some pleomorphism, but low mitotic activity
● Nodular fasciitis - not infiltrative, not deep, lacks chromosomal anomalies
● Solitary fibrous tumor
Additional references
=========================================================================
End of Breast – Malignant, Males, Children > Low grade myofibroblastic sarcoma
This information is intended for physicians and related personnel, who understand that medical information is often imperfect, and must also be interpreted in the context of a patient's clinical data using reasonable medical judgment. This website should not be used as a substitute for the advice of a licensed physician.
All information on this website is protected by Copyright, (c) 2001-2009, PathologyOutlines.com, Inc. Information from third parties may also be protected by copyright. Please contact us at copyrightPathOut@gmail.com with any questions.