Home Chapter Home Jobs Conferences Fellowships Books
Skin / Soft Tissue Tumors
Atypical fibrous histiocytoma
Author: Nat Pernick, M.D., PathologyOutlines.com, Inc.
Reviewer: David Lucas, M.D., University of Michigan Health Systems (January 2009)
Revised: 26 June 2009, last major update June 2009
Definition
=========================================================================
● Cellular, circumscribed dermal lesion of spindled fibroblasts, myofibroblasts, histiocyte-like cells and often giant cells
● Marked nuclear pleomorphism and mitotic figures (often atypical)
● No tumor cell necrosis
● No vascular invasion
Terminology
=========================================================================
● Rare variant of cutaneous fibrous histiocytoma
● Also called pseudosarcomatous fibrous histiocytoma or dermatofibroma with monster cells
● Part of WHO classification for skin tumors, not soft tissue tumors
● First described in 1983 (J Cutan Pathol 1983;10:327)
Epidemiology
=========================================================================
● Median age 38 years (range 5-79 years), no gender preference
Sites
=========================================================================
● Solitary lesions usually arise on extremities or trunk (Am J Dermatopathol 1986;8:467)
● Also head and neck, vulva
Case reports
=========================================================================
● 25 year old woman with recurrent leg lesion (Eur J Dermatol 1998;8:122)
● 62 year old woman with leg lesion (Tokai J Exp Clin Med 2004;29:49)
● 64 year old woman with 3 cm back lesion (Am J Dermatopathol 2002;24:36)
● 79 year old woman with leg lesion (Am J Dermatopathol 1997;19:312)
● 90 year old man with scrotal lesion (Ann Diagn Pathol 2003;7:370)
Treatment and prognosis
=========================================================================
● May be misdiagnosed as sarcoma (Histopathology 1990;17:167)
● Complete excision with negative margins
● Occasional local recurrence (14%) or distant metastasis (AJSP 2002;26:35)
Gross description
=========================================================================
● Median 1.5 cm (0.4 to 8 cm), nodular or polypoid
Micro description
=========================================================================
● Involvement of dermis and superficial subcutaneous tissue by pleomorphic, plump, spindle or polyhedral cells with large hyperchromatic, irregular or bizarre nuclei
● Background of classic fibrous histiocytoma including spindle cells with storiform pattern and entrapped thick collagen bundles, especially at the periphery
● Variable multinucleated giant cells, often with bizarre nuclei (“monster cells”, Am J Dermatopathol 1987;9:380) and foamy or hemosiderin-rich cytoplasm
● 0-15 mitotic figures/10 HPF, frequently atypical
● Necrosis occasionally present
Micro images
=========================================================================
Enlarged cells with hyperchromatic nuclei, but no / rare mitotic figures (source: AFIP Fascicle, 3rd series)
Positive stains
=========================================================================
● Vimentin, CD34 (occasionally)
Negative stains
=========================================================================
● CD68, S100, keratin (MNF116), EMA; <1% positive for MIB1 (Am J Dermatopathol 2004;26:367)
Differential diagnosis
=========================================================================
● Atypical fibroxanthoma - sun damaged areas of head and neck in elderly, presents as dome shaped or ulcerated nodule, tumor cells abut epidermis without a grenz zone (defined as relatively normal collagen forming a boundary between normal epidermis and a dermal lesion), also marked actinic elastosis, no classic features of fibrous histiocytoma
● Pleomorphic sarcoma - infiltrative, marked atypia, brisk mitotic activity, necrosis; no classic features of fibrous histiocytoma
● Pleomorphic fibroma - hypocellular, no epidermal hyperplasia, no classic features of fibrous histiocytoma
End of Skin / Soft Tissue Tumors > Atypical fibrous histiocytoma
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.