Skin nonmelanocytic tumor
Fibrous, fibrohistiocytic and myofibroblastic neoplasms
Dermatofibroma (cutaneous fibrous histiocytoma)-cellular


Topic Completed: 1 August 2012

Minor changes: 9 December 2020

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PubMed Search: Cellular fibrous histiocytoma

Vijay Shankar, M.D.
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Cite this page: Shankar V. Dermatofibroma (cutaneous fibrous histiocytoma)-cellular. PathologyOutlines.com website. https://www.pathologyoutlines.com/topic/softtissuefhcellular.html. Accessed January 16th, 2021.
Definition / general
  • More cellular than classic fibrous histiocytoma, elongated cells are arranged in storiform pattern or fascicles
Clinical features
  • 5% of dermal fibrous histiocytomas
  • Young or middle-aged adults, 60% men
  • Extremities or head and neck are most common
Treatment
Gross description
  • Up to 2.5 cm, rarely can be giant and multinodular mimicking dermatofibrosarcoma protuberans
Microscopic (histologic) description
  • Fascicular or storiform but no “tight” storiform pattern
  • Cells are plumper than DFSP, with eosinophilic cytoplasm and tapering nuclei; may entrap dermal collagen
  • Mean 3 mitotic figures / 10 HPF but may be > 10 MF / 10 HPF
  • Extension into subcutaneous fat in 1/3 cases
  • At least focal inflammatory cells, foam cells or giant cells
  • Epidermal changes in the form of hyperplasia in 58%, focal central necrosis in 12%
Microscopic (histologic) images

AFIP images

More cellular than classic fibrous histiocytoma

Elongated cells are arranged in fascicles or a storiform pattern

Tumor cells are more histiocyte like and foam cells are present



Images hosted on other servers:

Hyperplastic and acanthotic epithelium

Spindled tumor resembles a leiomyoma

Positive stains
Differential diagnosis
  • Dermatofibrosarcoma protuberans: tight storiform pattern, less polymorphic, cells more spindly than cellular fibrous histiocytoma, CD34+ (strong), Factor XIIIa negative
  • Leiomyosarcoma: smooth muscle morphology with cigar shaped nuclei, more pleomorphism, infiltrative dermal growth, muscle markers+
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