Table of Contents
Definition / general | Case reports | Treatment | Clinical images | Gross description | Microscopic (histologic) description | Microscopic (histologic) images | Positive stains | Negative stains | Differential diagnosisCite this page: Hale CS, Shankar V. Deep fibrous histiocytoma. PathologyOutlines.com website. https://www.pathologyoutlines.com/topic/skintumornonmelanocyticdeepbfh.html. Accessed June 7th, 2023.
Definition / general
- Fibrous histiocytoma of subcutaneous tissue, deep soft tissue or parenchymal organs, with no dermal involvement (Am J Surg Pathol 1994;18:677, Am J Surg Pathol 1990;14:801, Stanford Medicine)
- Rare painless lesions, < 1% of fibrohistiocytic tumors
- Usually adult males > 25 years (range 6 - 84 years)
- Usually extremities, head and neck, trunk; rarely in deep soft tissue of retroperitoneum, mediastinum or pelvis
Case reports
- 25 year old woman with painful foot mass (Ann Dermatol 2011;23:S239)
- 36 year old man with parotid mass (Case of the Week #360)
Treatment
- Excision
- Usually benign behavior but may recur if incompletely excised, rare metastases (Am J Surg Pathol 2008;32:354)
Gross description
- Well circumscribed with pseudocapsule, typically 4 cm (range 0.5 to 25 cm), variable hemorrhage
Microscopic (histologic) description
- Prominent storiform pattern of uniform spindle cells with ill defined eosinophilic cytoplasm and bland, elongated or plump vesicular nuclei with no atypia
- Often hemangiopericytoma-like vasculature
- Scattered lymphocytes, either multinucleated giant cells, osteoclastic giant cells or foam cells in 59%
- Usually less than 5 mitotic figures / 10 HPF
- Stroma is myxoid or hyaline
- Borders are non-infiltrative, with no trapping of fat cells
- Necrosis or angiolymphatic invasion are rare
Microscopic (histologic) images
Positive stains
- CD34 (40%), smooth muscle actin (38%)
Differential diagnosis
- Dermatofibrosarcoma protuberans: not circumscribed, usually infiltrative borders, tight storiform pattern, uniform cellularity, usually no foam cells, not sclerotic, strongly CD34+, Factor XIIIa weak / negative (Semin Cutan Med Surg 1999;18:91, Am J Surg Pathol 1994;18:677)
- Nodular fasciitis: loose collagenous stroma, myxoid, mixed inflammatory cells, thin walled blood vessels
- Solitary fibrous tumor: patternless (not storiform), alternating hypo- and hypercellular areas, prominent collagen fibers, no histiocytes, strongly CD34+