This is a distinctive benign fibrous soft tissue tumour that was first described by Evans in 1995.

Clinical presentation:  The lesion presents as a firm, well circumscribed, painless mass of long duration and are commonly located in the subcutaneous tissue or skeletal muscle in adults. The tumours range in size from 1 to 20 cm. 

Site:  This entity has been reported in various locations, including the upper extremities, posterior neck, upper back, lower extremities, abdominal wall, and hip.

Gross:  Macroscopically, the lesion presents as an elongated, lobulated, or disc-shaped mass with a firm consistency and a homogeneous grayish-white colour.

Microscopic features: Image1 ; Image2

The tumour is relatively hypocellular. There is proliferation of bland  spindle or stellate shaped cells embedded in a fibromyxoid to densely fibrotic collagenous stroma.   The stroma may contain a large amount of mucin which is positive with alcian blue.

Mitotic figures are very rare or absent, tumour necrosis is not seen, and vascularity is low.

The tumour often focally infiltrate the surrounding skeletal muscle and adipose tissue.

Immunohistochemistry:  Diffusely positive for vimentin. In some cases there may be focal staining for smooth muscle actin.   S-100,  EMA , CD34, desmin  and keratin are usually negative.

Electron microscopy : Revealed features consistent with a fibroblastic or myofibroblastic lineage.

Differential diagnosis:   Fibromatosis-   Collagenous fibroma should be differentiated from fibromatosis, which has a high risk of local recurrence if simple local excision is done.  Fibromatosis is more cellular and shows short fascicular arrangements of tumour cells and greater infiltration at the periphery than collagenous fibroma.
Neurofibroma;  Nodular fasciitis ;  Fibroma of tendon sheath ; Solitary fibrous tumour;  Perineurioma ;  low-grade fibromyxoid sarcoma.

The tumour did not recur after complete surgical excision.

Abstract: Desmoplastic fibroblastoma. A report of seven cases. Am J Surg Pathol.1995;19(9) :1077-81. Collagenous fibroma (desmoplastic fibroblastoma): a new case originating in the palate.Dentomaxillofac Radiol. 2005 ;34(2):117-9. Collagenous fibroma (desmoplastic fibroblastoma).Yonsei Med J.2004 31;45(5): 941-3. Desmoplastic fibroblastoma: a light and ultrastructural description of two cases.Ultrastruct Pathol. 2004 May-Jun;28(3):149-57. Collagenous fibroma (desmoplastic fibroblastoma) of the finger in a child. Pathol Int. 2002;52(4):322-5. Superficial collagenous fibroma: immunohistochemical, ultrastructural, and flow cytometric study of three cases, including one pemphigus vulgaris patient with a dermal mass. APMIS. 2002;110(4):283-9. Collagenous fibroma (desmoplastic fibroblastoma) of the palate: a case report.Oral Surg Oral Med Oral Pathol Oral Radiol Endod. 2001;91(1):80-4. Collagenous fibroma (desmoplastic fibroblastoma): a unique presentation as a goiter in an 88-year-old man. Ann Diagn Pathol. 2000;4(3):165-9. Collagenous fibroma of the arm: a report of two cases.Skeletal Radiol. 2000;29(7): 417- 20 The morphological characteristics of desmoplastic fibroblastoma. Zhonghua Bing Li Xue Za Zhi. 2000;29(5):331-3. Collagenous fibroma (desmoplastic fibroblastoma): a report of seven cases. Mod Pathol. 1996;9(7):781-5. Collagenous fibroma (desmoplastic fibroblastoma): report of four cases and review of the literature. Arch Pathol Lab Med. 1998;122(5):455-60. Collagenous fibroma (desmoplastic fibroblastoma): a clinicopathologic analysis of 63 cases of a distinctive soft tissue lesion with stellate-shaped fibroblasts. Hum Pathol. 1998;29(7):676-82. Desmoplastic fibroblastoma. J Cutan Pathol. 1998;25(8):450-4. Desmoplastic fibroblastoma (collagenous fibroma).Am J Dermatopathol. 1999;21 (3):256-8. Collagenous fibroma (desmoplastic fibroblastoma): genetic link with fibroma of tendon sheath?Mod Pathol. 1999;12(6):565-8 Collagenous fibroma (desmoplastic fibroblastoma): a distinctive fibroblastic soft tissue tumor. Adv Anat Pathol. 1999;6(5):275-80. Collagenous fibroma (desmoplastic fibroblastoma) presenting as a parotid mass. J Oral Pathol Med. 1999;28(10):465-8.                            Your Ad Here        Custom Search Soft Tissue Pathology; Myxoid Tumours of Soft Tissue ;  Classification of Soft Tissue Tumour;  Gross examination of soft tissue specimen ;  A practical approach to histopathological reporting of soft tissue tumours ;  Grading of soft tissue tumours ; Lipomatous tumours ;Neural tumours ; Myogenic tumours ;Vascular tumours ;Fibroblastic/Myofibroblastic tumours ; Myofibroblastic tumours ;  Fibrohistiocytic tumours ; ChondroOsseous tumours ; Soft TissueTumours of Uncertain Differentiation ; Notochordal Tumour -Chordoma ;Extra-adrenal Paraganglioma ; Gastrointestinal Stromal Tumour ;