Skin nonmelanocytic tumor
Fibrous, fibrohistiocytic and myofibroblastic neoplasms
Fibrous histiocytoma-cellular
Author: Vijay Shankar, M.D.
Topic Completed: 1 August 2012
Minor changes: 21 July 2020
Copyright: 2002-2018, PathologyOutlines.com, Inc.
PubMed Search: Cellular fibrous histiocytoma
Table of Contents
Definition / general | Clinical features | Treatment | Gross description | Microscopic (histologic) description | Microscopic (histologic) images | Positive stains | Negative stains | Differential diagnosisCite this page: Shankar V. Fibrous histiocytoma-cellular. PathologyOutlines.com website. https://www.pathologyoutlines.com/topic/softtissuefhcellular.html. Accessed October 21st, 2020.
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
- Excision
- 26% recur (Am J Surg Pathol 1994;18:668)
- Rare metastases (Am J Surg Pathol 1996;20:1361)
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
Images hosted on PathOut servers:
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
- Vimentin, CD163, CD68 (83%, J Cutan Pathol 2006;33:353)
- CD63 / NKI-C3 (50%), Factor XIIIa (48%), focal smooth muscle actin
- HMGA1, HMGA2, CD10, focally CD34+
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+
