Surgical Pathology Criteria

Deep Fibrous Histiocytoma

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

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