Table of Contents
Definition / general | Terminology | Clinical features | Case reports | Treatment | Clinical images | Gross description | Microscopic (histologic) description | Microscopic (histologic) images | Positive stains | Negative stains | Electron microscopy description | Molecular / cytogenetics description | Differential diagnosisCite this page: Shankar, V. Aneurysmal fibrous histiocytoma. PathologyOutlines.com website. http://www.pathologyoutlines.com/topic/softtissuefhaneurysmal.html. Accessed April 25th, 2018.
Definition / general
- Rare variant with dermal spindle cells and lakes of blood, but no endothelium
Terminology
- First described in 1981 (Cancer 1981;47:2053)
- Early lesion also called hemosiderin variant of fibrous histiocytoma
- Similar to sclerosing hemangioma variant of fibrous histiocytoma, which has more prominent capillaries, but differs from lung lesion called sclerosing hemangioma
Clinical features
- Usually extremities or trunk; often pigmented, rapid growth and pain (J Clin Pathol 1996;49:313)
- May have history of trauma (J Korean Med Sci 1989;4:159)
Case reports
- 10 year old girl with leukemia (Pediatr Dermatol 2006;23:591)
- 38 year old man with abdominal lesion called hemosiderotic variant (Dermatology 2007;214:82)
- 48 year old woman with recurrent tumor (J Clin Pathol 2004;57:312)
Treatment
- Excision
- Tends to recur if there is incomplete excision
- Rarely metastasizes
Clinical images
Gross description
- Blue, black or dark red cystic nodule
- Size varies from 0.5 to 4 cm
- Rarely presents as atrophic patch
Microscopic (histologic) description
- Storiform pattern of fibrohistiocytic cells (as in classic fibrous histiocytoma), but many cells are filled with hemosiderin
- Also large cystic spaces filled with blood, but without an endothelial lining
- Bizarre cells often present
- May have hemangiopericytoma-like pattern of cysts
- Periphery may have hyalinized collagen bundles surrounded by tumor cells (Histopathology 1995;26:323)
- Usually epidermal hyperplasia
- May have up to 10 MF / 10 HPF
- Dermoscopy description: Multicomponent pattern with central blue / red homogeneous area, white structures, peripheral delicate pigment network and vascular structures (Br J Dermatol 2006;154:244); this pattern also present in some melanomas
Microscopic (histologic) images
Positive stains
- Vimentin, Factor XIIIa (in areas without hemosiderin, J Dermatol 2002;29:744)
- Variable NKI-C3 (60%), smooth muscle actin (45%)
Negative stains
- CD31, CD34 (confirms that cysts do not contain endothelium), Factor VIIIa, CD68
- Actin, desmin, cytokeratin, Ki67
Electron microscopy description
- Hemosiderin containing histiocyte-like cells, fibroblast-like cells and intermediate cells
- No prominent proliferation of endothelial cells (Am J Dermatopathol 1995;17:179)
Molecular / cytogenetics description
- Single case report of recurrent tumor with t(12;19) (Cancer Genet Cytogenet 2006;164:155)
Differential diagnosis
- Angiomatoid fibrous histiocytoma: thick pseudocapsule, marked chronic inflammatory infiltrate and cystic areas of hemorrhage
- Angiosarcoma: lined by endothelial cells, variable atypia (APMIS 2006;114:744)
- Kaposi’s sarcoma: endothelial lined vessels are present (CD31+, CD34+), KSHV / HHV8+
- Spindle cell hemangioendothelioma: thick walled muscular blood vessels, organizing thrombi