Skin - Nonmelanocytic tumors
Other tumors of skin
Dermatofibrosarcoma protuberans (DFSP)

Author: Christopher Hale, M.D. (see Authors page)

Revised: 17 August 2016, last major update September 2012

Copyright: (c) 2002-2016, PathologyOutlines.com, Inc.

PubMed Search: Dermatofibrosarcoma protuberans [title]

See also: Myxoid variant, Sarcomas

Definition / General
  • Part of WHO classification for skin tumors, not soft tissue tumors
  • Low to intermediate grade malignancy, usually of dermis, with prominent storiform pattern of monomorphic fibroblast-like cells that invade into subcutis (eMedicine)
  • Also called intermediate (borderline) fibrous histiocytoma
  • Slow growing, low-grade malignant neoplasm of trunk and various sites but not hands and feet
  • Rare, usually adults 20 - 40 years, more common in blacks in US (J Am Acad Dermatol 2007;56:968)
  • Can occur in infants (Arch Dermatol 2007;143:203) and children (J Plast Reconstr Aesthet Surg 2009;62:819)
  • May be a peculiar type of nerve sheath tumor since CD34 positive, or may derive from a subset of CD34 positive dermal dendritic cells
  • Locally aggressive, low rate of metastasis (only after repeated failures at local control)
  • May progress to fibrosarcoma or MFH
  • Giant cell fibroblastoma is considered the juvenile variant of DFSP as it has the same translocation (Am J Surg Pathol 2003;27:27)

  • Bednar's tumor:
    • 5 - 10% of cases
    • Pigmented variant due to dendritic cells with melanin, S100+ only in pigmented cells, HMB45 negative
    • Associated with black patients

  • Indeterminate lesions between DFSP and dermatofibroma
    • Report of 10 tumors with features of both tumors, all Factor XIIIa+, CD34+, although in different cells (Am J Surg Pathol 2000;24:996)
    • Clinically, one recurrence at mean 22 months follow-up
    • Recommend complete excision
    • Cytogenetics may help distinguish
Case Reports
Treatment
Clinical Images

Images hosted on PathOut servers:
Courtesy of Mark R. Wick, M.D.

Abdominal skin, CT scan

Atrophic

Giant facial

Recurrent



Images hosted on other servers:

Papulonodular thigh lesions

Before and after Imatinib treatment

Gross Description
  • Nodular, polypoid or plaque-like, centered in dermis, can occur in deep soft tissue
  • Mean 5 cm, gray-white (brown/black if melanocytes present), may appear circumscribed
  • Hemorrhage and necrosis are rare
Micro Description
  • Non circumscribed, highly cellular, tight storiform pattern (cells radiating in spokes at right angles around a central point that often contains a vessel) that infiltrates deeply into subcutaneous tissue and entraps fat cells to form characteristic honeycomb pattern
  • Some tumors show areas of fascicular growth
  • Storiform pattern may be absent in early plaque stage
  • Cells are monomorphic, thin and spindly with scant eosinophilic cytoplasm and hyperchromatic nuclei resembling neurofibroma
  • May have numerous mitotic figures, but not atypical ones
  • Collagen usually non-polarizable and thin
  • Only mild pleomorphism and focal atypia
  • May coexist with giant cell fibroblastoma
  • Usually no significant pleomorphism, no / rare histiocytes, no histiocyte-like cells, no foam cells, no giant cells or other inflammatory cells
  • Variants: Atrophic (depressed lesion), collagenous (with central thick collagen bundles), granular cell (S100 negative), myxoid (see below), palisading, pigmented, sclerosing
Micro Images

Images hosted on PathOut servers:

Small uniform cells
radiating like pinwheels
from central area that has
a blood vessel is characteristic

Uniform cells with no significant
pleomorphism, minimal intercellular
collagen, but no / rare foam cells or
giant cells (characteristic of benign
fibrous histiocytoma)

Residual fat cells are in linear
arrangement resembling a string of
pearls, characteristic of DFSP but not
benign fibrous histiocytoma



Fine strands of collagen are present

Infiltration of fat causes tumor cells to surround fat cells

DFSP with diminished storiform pattern but CD34+ (not shown)

Pigmented cells are not common



Courtesy of Mark R. Wick, M.D.

Atrophic

Dedifferentiated, MFH like

Fibrosarcomatous





Breast skin

Breast skin, CD34



Images hosted on other servers:

Variants: with fibrosarcomatous
component, myxoid, pigmented

Cytology Description
  • Homogeneous with isolated spindle cells, often tissue fragments with storiform pattern, fibrillary stromal fragments, naked nuclei
  • Occasional slight to moderate atypia (Diagn Cytopathol 2004;30:261)
Electron Microscopy Description
  • Stellate or spindle cells with long, slender, ramified cell processes joined by primitive junctions, often with subplasmalemmal densities
  • Commonly multivesicular buds (Ultrastruct Pathol 2006;30:283)
Molecular / Cytogenetics Description
Differential Diagnosis
  • Dermatofibroma: also storiform but non-infiltrative, less cellular than DFSP, Factor XIIIa positive, CD34 negative
  • Thymoma: storiform but different location, CD34 negative
  • MFH-pleomorphic or atypical fibroxanthoma: storiform pattern but also moderate/marked pleomorphism and nuclear atypia