cutaneous fibrous histiocytoma

Cutaneous Fibrous Histiocytoma (CFH) Description

Cutaneous fibrous histiocytoma, also known as dermatofibroma, is a common benign skin tumor that typically presents as a firm dermal papule or nodule. It most commonly occurs on the lower limbs.

• Size and Location: The lesion is usually small, measuring 1 cm or less in diameter, and can be found on the extremities.
• Appearance: CFH appears as a firm tan-brown nodule, which can be flat or depressed in some cases.
• Histological Characteristics: Histologically, CFH is characterized by coarse collagen deposition and a mixture of fibroblastic cells, macrophages, and collagen.

Variants

There are several histological variants of dermatofibroma, including:

• Cellular benign fibrous histiocytoma (CBFH)
• Aneurysmal dermatofibroma
• Other rare variants

These variants may have distinct morphological features but share the same clinical behavior as CFH.

References

[1] Dermatofibroma is a common benign skin tumour which presents as a firm dermal papule or nodule, most commonly on the lower limbs. Histologically it is characterised by coarse collagen deposition and a mixture of fibroblastic cells, macrophages, and collagen. [8] [3] Briefly, benign fibrous histiocytoma is a tumour most commonly encountered as a solitary polypoid, flat or depressed lesion in the extremities of young to middle-aged adults, more frequently females. 3 In a proportion of cases it is multiple, occasionally in the setting of immunosupression. [12] [13] Fibrous histiocytoma is a common benign (non-cancerous) skin tumour. It is made up of a combination of fibroblastic cells, macrophages, and collagen, a type of connective tissue. The tumour develops in a layer of skin called the dermis. Another name for a fibrous histiocytoma is dermatofibroma. [13] [14] Cellular benign fibrous histiocytoma (CBFH) is a distinctive variant of fibrous histiocytoma, described as an entity by Calonje et al. in 1994, and represents about 5% of cutaneous benign fibrous histiocytomas. [14]

Cutaneous fibrous histiocytoma, also known as dermatofibroma, can be diagnosed through a combination of clinical evaluation and diagnostic tests.

• Clinical Evaluation: The diagnosis is often made clinically based on the patient's history and physical examination. A patient history of a solitary, slow-growing cutaneous nodule on the extremities of young to middle-aged adults, often female, is consistent with dermatofibroma [11].
• Immunohistochemical Stains: Immunohistochemical stains can be performed on a biopsy specimen to confirm the diagnosis. The cells are typically positive for factor XIIIa and negative for CD34 [1].
• Ultrasound: Ultrasound imaging can help visualize the soft tissues inside the body, which can aid in the diagnosis of cutaneous fibrous histiocytoma [3].
• **Magnetic Reson

Differential Diagnosis of Cutaneous Fibrous Histiocytoma

Cutaneous fibrous histiocytoma, also known as dermatofibroma, is a common benign skin tumor that can be challenging to diagnose due to its similarity in appearance with other types of tumors. The differential diagnosis for cutaneous fibrous histiocytoma includes:

• Atypical Fibroxanthoma: A rare and aggressive form of skin cancer that can mimic the appearance of fibrous histiocytoma.
• Dermal Leiomyosarcoma: A type of soft tissue sarcoma that can be mistaken for fibrous histiocytoma due to its similar histological features.
• Atypical Fibrous Histiocytoma: A rare variant of cutaneous fibrous histiocytoma that has a tendency to recur locally and metastasize, although very rarely.
• Aneurysmal Fibrous Histiocytoma: A rare variant of dermatofibroma that typically represents less than 2% of cases, characterized by its aneurysmal appearance.
• Epithelioid Fibrous Histiocytoma: A rare and aggressive variant of cutaneous fibrous histiocytoma that can be mistaken for other types of tumors due to its epithelioid morphology.

Key Features to Consider

When differentiating between these conditions, the following features should be considered:

• Histological Appearance: The presence of spindle cells, histiocytes, and collagen fibers in cutaneous fibrous histiocytoma.
• Immunohistochemical Stains: Positive staining for factor XIIIa and negative staining for CD34 can support the diagnosis of cutaneous fibrous histiocytoma.
• Clinical Presentation: The typical presentation of cutaneous fibrous histiocytoma as a firm subcutaneous nodule or papule, often with a history of minor trauma to the area.

References

[4] Dermatofibroma (superficial benign fibrous histiocytoma) is a common cutaneous nodule of unknown etiology. [10] Dermatofibroma, also known as fibrous histiocytoma, is a common, benign, cutaneous soft-tissue lesion characterized by firm subcutaneous nodules. [11] The term "fibrous histiocytoma" primarily describes the morphologic appearance of the cell populations forming these lesions rather than solely indicating the cellular lineage.