Soft tissue

Fibroblastic / myofibroblastic

Dermatofibrosarcoma protuberans (DFSP)

Editor-in-Chief: Debra L. Zynger, M.D.
Anjelica Hodgson, M.D.
Brendan C. Dickson, M.D., M.Sc.

Last author update: 7 November 2019
Last staff update: 10 April 2023 (update in progress)

Copyright: 2002-2023,, Inc.

PubMed Search: Dermatofibrosarcoma protuberans DFSP [title]

Anjelica Hodgson, M.D.
Brendan C. Dickson, M.D., M.Sc.
Page views in 2022: 64,296
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Cite this page: Hodgson A, Dickson B. Dermatofibrosarcoma protuberans (DFSP). website. Accessed June 4th, 2023.
Definition / general
Essential features
ICD coding
  • ICD-O: 8832/3 - dermatofibrosarcoma protuberans, NOS
  • ICD-O: 8833/3 - pigmented dermatofibrosarcoma protuberans
  • ICD-O: 8834/1 - giant cell fibroblastoma
  • Fibrosarcomatous dermatofibrosarcoma protuberans: no distinct coding identified
  • Can ostensibly involve any area of skin but the trunk and extremities are the most common locations
  • Tumors are generally presumed to occur sporadically
  • Virtually all cases contain fusion genes; COL1A1::PDGFB is the most common fusion product, although others have been reported
  • Possible association with adenosine deaminase deficient severe combined immunodeficiency (J Allergy Clin Immunol 2012;129:762)
Clinical features
  • Classically an exophytic, nodular cutaneous mass; however, often initially presents as a flat plaque (JAMA Netw Open 2019;2:e1910413)
  • Initially may show persistent slow growth, often for many years, then sudden progression (Cancer 1962;15:717)
  • Progression may occur with fibrosarcomatous transformation
  • Tumors are morphologically distinctive and frequently amenable to classification on the basis of microscopic tissue examination
  • Immunohistochemistry for CD34 is a useful adjunct as most cases are diffusely positive
  • Molecular testing is helpful, particularly in the context of limited sampling or unusual morphology
Radiology description
Radiology images

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Multiple examples from

Prognostic factors
  • Incomplete resection is a risk factor for recurrence
  • Fibrosarcomatous transformation (fibrosarcoma ex-DFSP) imparts an increased risk of recurrence and metastasis (Am J Surg Pathol 2006;30:436)
  • Metastases typically occur following multiple local recurrences
  • Increased age, male sex and tumor size are associated with worse overall survival (JAMA Dermatol 2016;152:1365)
Case reports
Clinical images

Contributed by Mark R. Wick, M.D.


Giant facial


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Papulonodular thigh lesions

Before and after imatinib treatment

Gross description
Gross images

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Scalp tumor

Microscopic (histologic) description
Microscopic (histologic) images

Contributed by Brendan C. Dickson, M.D., M.Sc.

Infiltration along fibrous septa

Honeycomb pattern

Nuclear monomorphism

Storiform pattern

Diffuse CD34 staining

Herringbone pattern in fibrosarcoma

Brisk mitotic activity in fibrosarcoma

Diminished CD34 in fibrosarcoma

Pigmented DFSP

Myxoid DFSP

DFSP post imatinib therapy

Case #485

Case #485


Virtual slides

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35 year old man with lesion on right upper arm

81 year old female with breast lesion

40 year old male with lesion on abdomen

27 year old male with lesion on abdomen

Positive stains
Negative stains
Electron microscopy description
Molecular / cytogenetics description
Molecular / cytogenetics images

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Fusion product of COL1A1 to PDGFB

PDGFB break apart FISH

Sample pathology report
  • Skin, back, biopsy:
    • Dermatofibrosarcoma protuberans
    • Comment: Within the dermis and subcutis there is a spindle cell neoplasm with a storiform pattern. The cytoplasm is eosinophilic. The nuclei are ovoid and monomorphic with rare mitotic activity. There is sparing of adnexal structures and infiltration of the subcutaneous fat with a "honeycomb" pattern. The cells are diffusely positive for CD34; they are negative for desmin, smooth muscle actin, S100 and keratin (AE1/AE3).
Differential diagnosis
  • Cellular fibrous histiocytoma:
    • Plump spindle cells with peripheral collagen entrapment
    • Inflammation, including foamy macrophages, lymphocytes and plasma cells often present; occasionally multinucleated giant cells (J Cutan Pathol 2012;39:747)
    • Immunohistochemistry for CD34 may highlight peripheral dermal fibroblasts; tumors may, rarely, be positive (J Cutan Pathol 2012;39:747)
  • Cutaneous leiomyosarcoma:
    • Plump spindle cells with a fascicular architecture
    • Ovoid / cigar shaped nuclei, atypical mitoses may be identified
    • Immunohistochemistry typically positive for desmin and h-caldesmon and negative for CD34
  • Solitary fibrous tumor:
    • Spindle cells with a patternless distribution; prominent branching vasculature
    • Keloid-like collagen bundles
    • Immunohistochemistry will additionally be positive for STAT6
Board review style question #1

    Which immunohistochemical stain is diffusely positive in typical dermatofibrosarcoma protuberans, the tumor shown in the photomicrograph?

  1. Pankeratin
  2. S100
  3. CD34
  4. Desmin
  5. HMB45
Board review style answer #1
C. CD34 is typically diffusely positive in cases of dermatofibrosarcoma protuberans while pankeratin, S100, desmin and HMB45 are not expressed.

Comment Here

Reference: Dermatofibrosarcoma protuberans (DFSP)
Board review style question #2
    The presence of which of the following fusion genes can be used to support a diagnosis of dermatofibrosarcoma protuberans in a primary dermal spindle cell neoplasm?

  1. JAZF1::SUZ12
  2. FUS::DDIT3
  3. COL1A1::PDGFB
  4. EWSR1::LI1
  5. MYB::NFIB
Board review style answer #2
C. The COL1A1::PDGFB fusion product is present in most cases of dermatofibrosarcoma protuberans. It is important to know that additional fusion genes are possible, which are missed by FISH or RT-PCR assays restricted to PDGFB. It is also important to know that other tumors may harbor this fusion product (e.g., uterus, cervix). The other fusion gene options have do not occur in dermatofibrosarcoma protuberans and are characteristic of other neoplasms:
  • JAZF1::SUZ12: low grade endometrial stromal sarcoma
  • FUS::DDIT3: myxoid liposarcoma
  • EWSR1::FLI1: Ewing sarcoma
  • MYB::NFIB: adenoid cystic carcinoma

Comment Here

Reference: Dermatofibrosarcoma protuberans (DFSP)
Board review style question #3

    Which of the following is true about this entity?

  1. Positive for Fontana-Masson & Factor XIIIa
  2. Positive for Prussian blue & Factor XIIIa
  3. Positive for Fontana-Masson & CD34
  4. Positive for Prussian blue & CD34
Board review style answer #3
C. Positive for Fontana-Masson & CD34. This is an example of pigmented dermatofibrosarcoma protuberans (Bednar tumor). The pigment is melanin which is positive with the Fontana-Masson stain, but not Prussian blue. The tumor cells are typically diffusely positive for CD34, but negative for Factor XIIIa.

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Reference: Dermatofibrosarcoma protuberans (DFSP)
Board review style question #4
The molecular pathogenesis of most cases of dermatofibrosarcoma protuberans is characterized by the following fusion gene product:

Board review style answer #4
C. COL1A1::PDGFB. COL6A3::PDGFD is only rarely encountered in dermatofibrosarcoma protuberans; COL6A3::CSF1 is found in a subset of tenosynovial giant cell tumors; COL1A1::USP6 may be present in myositis ossificans, fibro-osseous pseudotumor of the digits and aneurysmal bone cyst.

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Reference: Dermatofibrosarcoma protuberans (DFSP)
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