Dermatofibroma overview

# Overview
Dermatofibroma is a common benign skin lesion which may develop in all age group. Although, it is more occurred in 20s to 40s ages. The majority of patients with dermatofibroma are asymptomatic. It mostly develops as a single slow  growing lesion on an extremity. Traumatized lesion may cause pain, bleeding, itching, erosive changes,and ulceration. Physical examination of patients with dermatofibroma is usually shows a non-tender, hyperpigmented nodule with 0.3 to 1 cm in diameter which dimple sign may be positive. It can seen in any part of the body but extremities, especially legs are most common sites. Dermatofibroma is primarily diagnosed based on the clinical presentation and history. They are benign and no treatment is generally needed. If the treatment is needed, local excision is the mainstay one.

# Historical Perspective
Dermatofibroma was first discovered by Unna, in 1894. He named it  as "fibroma durum".

# Classification
Dermatofibroma may be classified according to histopathology into three groups, variants that are prominent in architectural (low-power) properties, variants that are prominent in cytologic or stromal (high-power) properties, and variants that have architectural (low) and cytological or stromal (high-power) properties.

# Pathophysiology
The exact pathogenesis of dermatofibroma is not fully understood. Although some mechanisms are suggested in the pathogenesis of this disease that include, reactive tissue changes, neoplastic proliferation, the cell surface proteoglycan, syndecan-1, and fibroblast growth factor receptor 2 may play a role in the growth of dermatofibromas, transforming growth factor-beta (TGF-beta) signaling may be involved in the development of fibrosis in dermatofibroma, and the presence of factor XIIIa and CD168 suggests that dermatofibroma can originate from the dermal dendritic cell. On gross pathology, firm yellowish papules which may have areas of hemorrhage and lipidization are characteristic findings of dermatofibroma. Microscopically dermatofibroma is characterized by localized nodular proliferation of spindle-shaped fibrous cells in a mixture of histocytoid cells inside the dermis, spiculated margin of cells, Storiform pattern which defines as whorls of elongated nuclei, collagen bundles that usually seen inside and between the fascicles of spindled fibrous cells, "Grenz zone" which is an unaffected layer that separates the overlying epidermis from the dermis, and epidermal hyperplasia.

# Causes
The causes of dermatofibroma has not been identified.

# Differentiating Dermatofibroma from Other Diseases
Dermatofibroma must be differentiated from other common causes of skin lesions, such as basal cell carcinoma, dermatofibrosarcoma protuberans, and Kaposi sarcoma.

# Epidemiology and Demographics
Dermatofibroma is a common benign skin lesion that is seen in almost 3000 dermatophatology laboratory specimens per 100,000 ones. As most of patients with dermatofibroma are asymptomatic, the worldwide incidence of dermatofibroma is unknown. Patients of all age groups may develop dermatofibroma. Although, it is more occurred in 20s to 40s ages. There is no racial predilection to dermatofibroma. Female are more commonly affected by dermatofibroma than male. The female to male ratio is approximately 2 to 1. Dermatofibromas are benign and no treatment is generally needed. If the treatment is needed, local excision is the mainstay one.

# Risk Factors
There are no established risk factors for dermatofibroma. Although, It is believed that minor trauma or a low-grade benign neoplasm can have role.

# Screening
There is insufficient evidence to recommend routine screening for dermatofibroma.

# Natural History, Complications, and Prognosis
Dermatofibroma usually develops in the third decade of life, and most of them are asymptomatic. Common complications of dermatofibroma are related to excisional removing of the lesion and include, bleeding, infection and scar. Prognosis is generally excellent. Although, in very rare cases metastases are seen.

# Diagnosis

## Diagnostic Study of Choice
Dermatofibroma is primarily diagnosed based on the clinical presentation and history.

## History and Symptoms
The majority of patients with dermatofibroma are asymptomatic. Dermatofibroma mostly develops as a single slow  growing lesion on an extremity. Traumatized lesion may cause pain, bleeding, itching, erosive changes,and ulceration.
Multiple dermatofibromas is a rare variant of disease which mostly seen in patients with underlying systemic disorders.

## Physical Examination
Physical examination of patients with dermatofibroma is usually shows a non-tender, hyperpigmented nodule with 0.3 to 1 cm in diameter which dimple sign may be positive. It can seen in any part of the body but extremities, especially legs are most common sites.

## Laboratory Findings
There are no diagnostic laboratory findings associated with dermatofibroma.

## Electrocardiogram
There are no ECG findings associated with dermatofibroma.

## X-ray
There are no x-ray findings associated with dermatofibroma.

## Ultrasound
Ultrasound may be helpful in the diagnosis of dermatofibroma. Findings on an ultrasound suggestive of dermatofibroma include hypoechoic solid nodule, avascular lesion within the dermis, and unwell defined margin.

## CT scan
There are no CT scan findings associated with dermatofibroma.

## MRI
There are no MRI findings associated with dermatofibroma.

## Other Imaging Findings
There are no other imaging findings associated with dermatofibroma.

## Other Diagnostic Studies
Dermatoscopy may be helpful in the diagnosis of dermatofibroma. Findings suggestive of dermatofibroma include central white patch with peripheral network of pigmentation.

# Treatment

## Medical Therapy
Dermatofibromas are benign and no treatment is generally needed. If the treatment is needed, local excision is the mainstay one.

## Interventions
Carbon dioxide and pulsed-dye laser can be used for the treatment of dermatofibroma.

## Surgery
Surgery is the first-line treatment option for patients with dermatofibroma. Surgery is usually used for patients with either cosmetic reasons, symptomatic lesions, uncertain diagnosis and aggressive subtypes.
Complete excision which is involved subcutaneous fat incorporated with 1-3 mm margin based on the location of lesion is recommended. Cryosurgery or superficial shaving as a purpose of cosmetic or controlling symptoms are accompanied by increasing risk of recurrence.

## Primary Prevention
There are no established measures for the primary prevention of dermatofibroma.

## Secondary Prevention
There are no established measures for the secondary prevention of dermatofibroma.