Stanford School of Medicine
Surgical Pathology Criteria
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Deep Fibrous Histiocytoma

Definition

  • Neoplasm with features of usual dermal fibrous histiocytoma but occuring in subcutaneous or deep soft tissue

Alternate / Historical Names

  • Deep benign fibrous histiocytoma

Diagnostic Criteria

  • Must have at least areas of histologic features of usual dermal fibrous histiocytoma
    • Spindled to plump ovoid cells
    • Indistinct cytoplasm
    • Bland cytology
      • Vesicular nuclei with small nucleoli
    • Storiform pattern
      • (Differs from dermal fibrous histiocytoma)
      • May also have areas of short fascicles
    • Variable numbers of interspersed lymphocytes
    • May also have foam cells and multinucleated giant cells
  • Located in subcutaneous tissue (91%) or deep visceral soft tissue (9%)
    • May be attached to fascia or tendon
  • Well circumscribed
    • Frequently with fibrous pseudocapsule
  • Mitotic figures range from 0-66/10 hpf
    • Median 3/10 hpf
  • Variable features
    • Staghorn blood vessels 42%
      • (Differs from dermal fibrous histiocytoma)
    • Focal stromal hyalinization 39%
    • Myxoid stroma 9%
    • Peripheral lymphoid infiltrate
      • May form germinal centers
    • Hemorrhage and or hemosiderin
      • May be aneurysmal
    • Cystic degeneration
    • Infarction
  • Rare findings
    • Metaplastic ossification (1/69 cases)
    • Vascular invasion (1/69)
  • Rare cases with features of atypical fibrous histiocytoma (6/69 cases)
    • Scattered large pleomorphic cells
      • Bizarre hyperchromatic or vesicular nuclei
      • Prominent nucleoli
    • Pleomorphic nuclei also seen in foam cells and multinucleated cells
    • Atypical mitotic figures
    • Tumor cell necrosis
      • Note that this was not considered a criterion for atypical fibrous histiocytoma in the publication of Gleason 2008, but one of their two cases with tumor cell necrosis metastasized.
  • (Only one up to date published series Gleason 2008)
  • 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
    Last update: December 30, 2008

 

Supplemental studies

Immunohistology

 
CD34 40%, may be extensive (differs from dermal fibrous histiocytoma)
Smooth muscle actin 38%, may be extensive (differs from dermal fibrous histiocytoma)
Desmin 8%, focal
EMA Negative

Differential diagnosis

Deep Fibrous Histiocytoma Solitary Fibrous Tumor
No bands of collagen separating cells Bands of collagen separate cells
Predominantly storiform Usually patternless
Histiocytic differentiation present No histiocytic differentiation
Usually uniform celllularity Alternating hypocellular and hypercellular areas
CD34 40% positive CD34 >95% positive (negative result favors fibrous histiocytoma)

 

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

 

Dermal and Deep Fibrous Histiocytoma Plexiform Fibrohistiocytic Tumor
No plexiform rays of fibrous tissue extending into fat Plexiform rays of fibrous tissue extending into fat
Histiocytes scattered throughout Nodules of histiocyte-like cells
Frequent xanthoma cells Xanthoma cells rare
Extravasated red blood cells infrequent Extravasated red blood cells frequent

 

Dermal and Deep Fibrous Histiocytoma Soft Tissue Perineurioma
Elongated bipolar cytoplasmic processes Cytoplasm indistinct
Usually has whorled areas Regular storiform pattern
EMA negative EMA positive

 

Tenosynovial Giant Cell Tumor Deep Fibrous Histiocytoma
Usually sheets of histiocytoid cells Spindled to ovoid cells
Lacks storiform pattern Storiform
Most on fingers and toes Rare on fingers and toes

 

Soft Tissue Giant Cell Tumor of Low Malignant Potential Deep Fibrous Histiocytoma
Infiltrating nodules Circumscribed nodule
Lacks storiform pattern Storiform
Frequent metaplastic bone Metaplastic bone rare

Lesions that may demonstrate a prominent hemangiopericytoma-like vascular pattern

Clinical

  • Median age 37
    • Range 6-84
  • Wide variety of locations
    • Extremities 58%
    • Deep soft tissue of mediastinum, retroperitoneum and pelvis 9%
  • Local recurrence in 27% of cases
    • None were widely excised
  • Distant metastases in 2/69 cases
    • One case had features of atypical fibrous histiocytoma
      • No pleomorphism but had tumor cell necrosis
    • One case primary in mediastinum
  • (Only one up to date published series Gleason 2008)

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
  • Fletcher CDM, Unni KK, Mertens F. Pathology and Genetics of Tumours of Soft Tissue and Bone, World Health Organization Classification of Tumours 2002
  • Weiss SW, Goldblum JR. Enzinger and Weiss's Soft Tissue Tumors, 5th edition, 2008
  • Billings SD, Folpe AL. Cutaneous and subcutaneous fibrohistiocytic tumors of intermediate malignancy: an update. Am J Dermatopathol. 2004 Apr;26(2):141-55.
  • Gleason BC, Fletcher CD. Deep "benign" fibrous histiocytoma: clinicopathologic analysis of 69 cases of a rare tumor indicating occasional metastatic potential. Am J Surg Pathol. 2008 Mar;32(3):354-62.
 
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