Soft tissue

Fibroblastic / myofibroblastic

Dermatofibrosarcoma protuberans (DFSP)


Editorial Board Member: Farres Obeidin, M.D.
Editor-in-Chief: Debra L. Zynger, M.D.
Anjelica Hodgson, M.D.
Brendan C. Dickson, M.D., M.Sc.

Last author update: 22 June 2023
Last staff update: 22 June 2023

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PubMed Search: Dermatofibrosarcoma protuberans

Anjelica Hodgson, M.D.
Brendan C. Dickson, M.D., M.Sc.
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Cite this page: Hodgson A, Dickson BC. Dermatofibrosarcoma protuberans (DFSP). PathologyOutlines.com website. https://www.pathologyoutlines.com/topic/skintumornonmelanocyticdfsp.html. Accessed April 15th, 2024.
Definition / general
  • Locally aggressive, superficial mesenchymal neoplasm with fibroblastic differentiation
Essential features
  • Locally aggressive, superficial mesenchymal neoplasm with fibroblastic differentiation
  • Virtually all cases contain fusion genes; COL1A1::PDGFB is the most common fusion product, although others have recently been reported
  • Fibrosarcomatous transformation imparts an increased risk of recurrence and metastasis
ICD coding
  • ICD-O:
    • 8832/3 - dermatofibrosarcoma protuberans, NOS
    • 8833/3 - pigmented dermatofibrosarcoma protuberans
    • 8834/1 - giant cell fibroblastoma
  • Fibrosarcomatous dermatofibrosarcoma protuberans: no distinct coding identified
Epidemiology
Sites
  • Can ostensibly involve any area of skin but the trunk and extremities are the most common locations
Pathophysiology
  • 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)
  • Fibrosarcomatous transformation is associated with metastatic potential (Cancer 2000;88:2711)
Diagnosis
  • Tumors are morphologically distinctive and frequently amenable to classification based on H&E
  • Immunohistochemistry for CD34 is a useful adjunct since most cases are diffusely positive
  • Molecular testing is helpful, particularly in the context of limited sampling or unusual morphology
Radiology description
Radiology images

Images hosted on other servers:
Multiple examples from radiopaedia.org

Nodular soft tissue mass

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
Treatment
Clinical images

Images hosted on other servers:
Papulonodular thigh lesions

Papulonodular thigh lesions

Before and after imatinib treatment

Before and after imatinib treatment

Gross description
Gross images

Images hosted on other servers:
Scalp tumor

Scalp tumor

Microscopic (histologic) description
Microscopic (histologic) images

Contributed by Brendan C. Dickson, M.D., M.Sc.
Infiltration along fibrous septa

Infiltration along fibrous septa

Honeycomb pattern

Honeycomb pattern

Nuclear monomorphism

Nuclear monomorphism

Storiform pattern

Storiform pattern

Herringbone pattern in fibrosarcoma ex DFSP

Herringbone pattern in fibrosarcoma ex DFSP

Brisk mitotic activity in fibrosarcoma ex DFSP

Brisk mitotic activity in fibrosarcoma ex DFSP


Pigmented DFSP

Pigmented DFSP

Myxoid DFSP

Myxoid DFSP

DFSP post imatinib therapy

DFSP post imatinib therapy

Diffuse CD34 staining

Diffuse CD34 staining

Diminished CD34 in fibrosarcoma ex DFSP

Diminished CD34 in fibrosarcoma ex DFSP

Virtual slides

Images hosted on other servers:
35 year old man with lesion on right upper arm

35 year old man with lesion on right upper arm

81 year old woman with breast lesion

81 year old woman with breast lesion

40 year old man with lesion on abdomen

40 year old man with lesion on abdomen

27 year old man with lesion on abdomen

27 year old man with lesion on abdomen

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

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Fusion product of <i>COL1A1</i> to <i>PDGFB</i> Fusion product of <i>COL1A1</i> to <i>PDGFB</i>

Fusion product of COL1A1 to PDGFB

<i>PDGFB</i> break apart FISH

PDGFB break apart FISH

Sample pathology report
  • Skin, back, biopsy:
    • Dermatofibrosarcoma protuberans (see comment)
    • 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 is often present, including foamy macrophages, lymphocytes and plasma cells; occasionally multinucleated giant cells (J Cutan Pathol 2012;39:747)
    • Immunohistochemistry for CD34 may highlight peripheral dermal fibroblasts; rarely, tumors may 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 also be positive for STAT6
Board review style question #1

Which immunohistochemical stain would be diffusely positive in typical dermatofibrosarcoma protuberans tumor (such as the one shown in the image above)?

  1. CD34
  2. Desmin
  3. HMB45
  4. Pankeratin
  5. S100
Board review style answer #1
A. CD34 is typically diffusely positive in cases of dermatofibrosarcoma protuberans while desmin, HMB45, pankeratin and S100 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. COL1A1::PDGFB
  2. EWSR1::FLI1
  3. FUS::DDIT3
  4. JAZF1::SUZ12
  5. MYB::NFIB
Board review style answer #2
A. COL1A1::PDGFB fusion product is present in most cases of dermatofibrosarcoma protuberans. It is important to note that additional fusion genes are possible but are missed by FISH or reverse transcription PCR assays that are restricted to PDGFB. It is also important to note that other tumors may harbor this fusion product (e.g., uterus, cervix). The other fusion gene options do not occur in dermatofibrosarcoma protuberans and are characteristic of other neoplasms:
  • EWSR1::FLI1: Ewing sarcoma
  • FUS::DDIT3: myxoid liposarcoma
  • JAZF1::SUZ12: low grade endometrial stromal sarcoma
  • MYB::NFIB: adenoid cystic carcinoma

Comment Here

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

Which of the following is true regarding the entity shown above?

  1. Positive for Fontana-Masson and CD34
  2. Positive for Fontana-Masson and factor XIIIa
  3. Positive for Prussian blue and CD34
  4. Positive for Prussian blue and factor XIIIa
Board review style answer #3
A. Positive for Fontana-Masson and 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 which of the following fusion gene products?

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

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Reference: Dermatofibrosarcoma protuberans (DFSP)
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