Stanford School of Medicine
Surgical Pathology Criteria
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Dermatofibrosarcoma Protuberans

Definition

  • Superficial infiltrative soft tissue neoplasm composed of bland spindle cells with a regular storiform pattern

Alternate / Historical Names

  • DFSP

Diagnostic Criteria

  • Cellular lesion composed of uniform small elongate cells
    • Scant cytoplasm
    • Cytologically bland, lacking pleomorphism
    • Mitotic rate usually <5/10 hpf
      • No atypical mitotic figures
  • Uniform storiform pattern
    • May be absent in early, plaque-like lesions
  • Infiltrates between and around fat cells and adnexa
    • Produces “string of pearls” or “honeycomb” or “lace-like” patterns
    • This is one of the most useful histologic features
  • Located in dermis and subcutaneous tissue
  • Inconspicuous vasculature
  • Scant collagenous stroma
  • Giant cells and foam cells almost always absent
  • CD34 extensively positive in nearly all cases
  • May have myxoid areas
    • May predominate resulting in a hypocellular lesion
    • May obscure storiform pattern
    • Diagnosis in such cases made from typical fat infiltration pattern in other areas and CD34 staining
  • Myoid whorls occasionally seen
    • Small collections of actin positive cells with abundant cytoplasm
    • May be centered on vessels
  • Very rare/unusual findings; if present, alternative diagnoses should be considered
    • Giant cells
    • Xanthoma cells
    • Hemosiderin
    • Inflammatory cells
  • Rare cases may contain areas with fibrosarcomatous features
    • Cellular plump spindled cells
    • Uniform high grade cytologic atypia
    • Frequent mitotic figures >5/10 hpf
    • Herringbone pattern of fascicles
    • Must make up at least 5-10% of the tumor or more than two low power fields
    • Occurs in primary lesions as well as recurrences
    • Clinical significance unclear
      • If widely resected, metastasis is rare
  • Very rare cases with appearance of MFH reported
    • Clinical significance unclear
  • Giant cell fibroblastoma is a closely related lesion
    • More common in pediatric age group
    • Mixtures may be seen
    • Recurrences may be of the other neoplasm
    • Same t(17;22) translocation
  • Bednar tumor is a pigmented DFSP
    • Contains elongate, bipolar heavily pigmented melanocytes
    • Melanocytes S100 positive, HMB45 negative
      • Remainder of tumor is negative
    • More numerous in deep portions of tumor
    • More common in black patients
  • Richard L Kempson MD
    Robert V Rouse MD
    Department of Pathology
    Stanford University School of Medicine
    Stanford CA 94305-5342

    Original posting: August 10, 2008

 

Supplemental studies

Immunohistology

CD34 Nearly 100%, extensive staining
Apolipoprotein D 90%
Factor XIIIa 75% but weak and focal
Actin Variable
Keratin Negative
S100 Negative
Desmin Negative

Genetic studies

t(17;22) with fusion of COL1A1 and PDGFB in all cases tested

Differential diagnosis

Dermal and Deep Fibrous Histiocytoma Dermatofibrosarcoma Protuberans
Usually <1 cm Frequently >2 cm
Haphazard short fascicles in dermal lesions; deep lesions frequently storiform Regular storiform pattern
Infrequent infiltration into and around fat cells Frequent infiltration into and around fat cells
Frequently mixed cell population Monomorphous cell population
Frequent overlying epithelial hyperplasia Overlying epithelium usually attenuated
CD34 40% in deep lesions, negative in dermal lesions CD34 100% extensive
Apolipoprotein D negative (deep lesions not tested) Apolipoprotein D 90%
Factor XIIIa >95% extensive Factor XIIIa 75% but focal and weak
CD34 and Factor XIIIa are difficult to interpret in many cases because of numerous entrapped reactive cells

 

Myxoid Nerve Sheath Tumor Myxoid Dermatofibrosarcoma Protuberans
Areas of typical nerve sheath tumor usually present Areas of typical storiform pattern usually present
S100 positive S100 negative
CD34 may stain scattered dendritic cells but not lesional cells CD34 stains lesional cells

 

Myxoid Liposarcoma Myxoid Dermatofibrosarcoma Protuberans
Usually involves deep soft tissue Usually involves dermis and superficial subcutaneous tissue
Frequently contains lipoblasts No lipoblasts
CD34 may stain scattered dendritic cells but not lesional cells CD34 stains lesional cells

 

Plexiform Fibrohistiocytic Tumor Dermatofibrosarcoma Protuberans
Ray-like extension into surrounding fat Infiltrates between and around individual fat cells
Collagenous stroma Usually contains only fine collagen
Nodules of histiocytes and giant cells in most cases Histiocytes and giant cells very rare
CD34 negative CD34 stains lesional cells
 

 

Desmoplastic Melanoma Dermatofibrosarcoma Protuberans
Lacks storiform pattern Prominent storiform pattern
Displaces or destroys fat Infiltrates between and around individual fat cells
Dense collagenous stroma Usually contains only fine collagen
Frequently contains lymphoid nodules Inflammatory cells infrequent
CD34 negative CD34 stains lesional cells
S100 positive S100 negative

 

Dermatofibrosarcoma Protuberans Adult or Infantile Fibrosarcoma
CD34 positive CD34 negative
Storiform pattern Fascicular, herringbone pattern
Involves dermis and subcutaneous tissue Virtually always in deep soft tissue
DFSP may dedifferentiate with a fibrosarcoma pattern
If fibrosarcoma occurs in the dermis or subcutaneous tissue, it is usually dedifferentiated DFSP

Clinical

  • Wide age range but most common 20-40 years of age
  • Trunk most common, followed by proximal extremities and head and neck
    • Very rare cases of similar appearing tumors in deep tissues and retroperitoneum
      • Same clinical behavior
  • Slow growth
  • Early lesions are plaque-like
  • Late lesions protuberant
  • 10-20% recur if widely excised
    • Frequent, aggressive recurrences if not widely excised
  • Metastases <5% if widely excised
  • Cases with areas of sarcoma appear to have the same behavior as usual cases if widely excised

Bibliography

  • Kempson RL, Fletcher CDM, Evans HL, Henrickson MR, Sibley RS. Tumors of the Soft Tissues, Atlas of Tumor Pathology, AFIP Third Series, Fascicle 30, 2001
  • Weiss SW, Goldblum JR. Enzinger and Weiss's Soft Tissue Tumors, 5th edition, 2008
  • Goldblum JR, Reith JD, Weiss SW. Sarcomas arising in dermatofibrosarcoma protuberans: a reappraisal of biologic behavior in eighteen cases treated by wide local excision with extended clinical follow up. Am J Surg Pathol. 2000 Aug;24(8):1125-30.
  • Mentzel T, Schärer L, Kazakov DV, Michal M. Myxoid dermatofibrosarcoma protuberans: clinicopathologic, immunohistochemical, and molecular analysis of eight cases. Am J Dermatopathol. 2007 Oct;29(5):443-8.
  • Goldblum JR, Tuthill RJ. CD34 and factor-XIIIa immunoreactivity in dermatofibrosarcoma protuberans and dermatofibroma. Am J Dermatopathol. 1997 Apr;19(2):147-53.
  • West RB, Harvell J, Linn SC, Liu CL, Prapong W, Hernandez-Boussard T, Montgomery K, Nielsen TO, Rubin BP, Patel R, Goldblum JR, Brown PO, van de Rijn M. Apo D in soft tissue tumors: a novel marker for dermatofibrosarcoma protuberans. Am J Surg Pathol. 2004 Aug;28(8):1063-9.
  • Billings SD, Folpe AL. Cutaneous and subcutaneous fibrohistiocytic tumors of intermediate malignancy: an update. Am J Dermatopathol. 2004 Apr;26(2):141-55.
 
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