Dermatofibroma

Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1], Associate Editor(s)-in-Chief: Homa Najafi, M.D.[2]Faizan Sheraz, M.D. [3]

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.

Dermatofibroma was first discovered by Unna, in 1894. He named it as “fibroma durum”.

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.

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.

The causes of dermatofibroma has not been identified.

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

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.

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

There is insufficient evidence to recommend routine screening for dermatofibroma.

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.

Dermatofibroma is primarily diagnosed based on the clinical presentation and history.

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 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.  

There are no diagnostic laboratory findings associated with dermatofibroma.

There are no ECG findings associated with dermatofibroma.

There are no x-ray findings associated with dermatofibroma.

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.

There are no CT scan findings associated with dermatofibroma.

There are no MRI findings associated with dermatofibroma.

There are no other imaging findings associated with dermatofibroma.

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

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

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

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.

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

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

Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1];Associate Editor(s)-in-Chief: Homa Najafi, M.D.[2]

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

• There is limited information about the historical perspective of dermatofibroma.

• Dermatofibroma was first discovered by Unna, in 1894. He named it as fibroma durum.^[1]

Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1];Associate Editor(s)-in-Chief: Homa Najafi, M.D.[2]

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.

Dermatofibroma may be classified according to histopathology into three groups:^{[1][2][3][4][5][6][7][8][9]}

• Variants that are prominent in architectural (low-power) properties
• Variants that are prominent in cytologic or stromal (high-power) properties
• Variants that have architectural (low) and cytological or stromal (high-power) properties

Histopathology varient of dermatofibroma

Variants that are prominent in architectural (low-power) properties

Variants that are prominent in cytologic or stromal (high-power) properties

Variants that have architectural (low) and cytological or stromal (high-power) properties

1. Deep penetrating dermatofibroma 2. Atrophic dermatofibroma 3. Aneurysmal fibrous histiocytoma 4. Haemangiopericytoma-like fibrous histiocytoma 5. Palisading cutaneous fibrous histiocytoma 6. Lichenoid, erosive, & ulcerated dermatofibroma 7. Plaque-like dermal fibromatosis, dermatofibroma

1. Clear cell dermatofibroma 2. Granular cell dermatofibroma 3. Myofibroblastic dermatofibroma 4. Sclerotic dermatofibroma 5. Keloidal dermatofibroma 6. Atypical/pseudosarcomatous fibrous histiocytoma, dermatofibroma with monster cells 7. Hemosiderrhotic dermatofibroma 8. Cholesterotic/lipidized dermatofibroma 9. Myxoid dermatofibroma 10. Ossifying dermatofibroma 11. Pseudolymphomatous dermatofibroma 12. Dermatofibroma with diffuse eosinophilic infiltrate

1. Epithelioid cell histiocytoma 2. Cellular benign fibrous histiocytoma 3. Smooth muscle proliferation in dermatofibroma 4. Multinucleate cell angiohistiocytoma 5. Cellular neurothekeoma 6. Combined dermatofibroma

Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1], Associate Editor(s)-in-Chief: Homa Najafi, M.D.[2]Faizan Sheraz, M.D. [3]

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.

• The exact pathogenesis of dermatofibroma is not completely understood.

• The mechanisms which are suggested in the pathogenesis of dermatofibroma include:^{[1][2][3][4][5][6][7]}
  • Reactive tissue changes
  • Neoplastic proliferation because of the clonality
  • 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
  • The presence of factor XIIIa and CD168 suggests that dermatofibroma can originate from the dermal dendritic cell.

• There is no genetic alteration involved with pathogenesis of dermatofibroma.

Conditions associated with multiple dermatofibromas include:^{[8][9][10][11][12][13][14][15]}

• Pregnancy
• Chromosomal alterations (Down syndrome)
• Metabolic disorders (hypertriglyceridemia)
• Hematologic malignancies
• Immunodeficient diseases (HIV)
• Autoimmune diseases (myasthenia gravis, pemphigus vulgaris, and systemic lupus erythematosus)

On gross pathology, firm yellowish papules which may have areas of hemorrhage and lipidization are characteristic findings of dermatofibroma.^[16]

Microscopically dermatofibroma is characterized by: ^[17][18][19]

• 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
• Epidermal hyperplasia

Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1];Associate Editor(s)-in-Chief: Homa Najafi, M.D.[2]

The causes of dermatofibroma has not been identified.

The causes of dermatofibroma has not been identified.

Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1];Associate Editor(s)-in-Chief: Homa Najafi, M.D.[2]

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

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

Diseases		Skin examination					Diagnosis		Additional findings
		Type	Color	Texture	Size	Distribution	Dermoscopic Findings	Histopathology
Dermatofibroma[1][2]		Nodule	Hyperpigmented	Firm	0.3- 1 cm	Mostly seen in extremities		Localized nodular proliferation of spindle-shaped fibrous cells in a mixture of histocytoid cells inside the dermis Spiculated margin of cells “Storiform” pattern Collagen bundles “Grenz zone” Epidermal hyperplasia	Slow growth over the years
dermatofibrosarcoma protuberans[3][4]		Patch Plaque	Skin–colored, violet or reddish–brown	Firm	1-5 cm	Mostly seen in trunk	Presence of vessels pigmented network pinkish background	Highly cellular with cells having following characteristics: Monomorphic Thin Spindly Scant eosinophilic cytoplasm Hyperchromatic nuclei (resembling neurofibroma)
Kaposi sarcoma[5][6]		Macule Patch	Red/violaceous	Smooth	Variable	Mucus membrane	Rainbow pattern scaly surface Small brown globules	Spindle cells with minimal nuclear atypia Excessive vascular proliferation Abundant red blood cells RBC and hemosiderin extravasation Abundant lymphocytes and monocytes Premonitory sign Intracytoplasmic PAS +ve hyaline globules	Kaposi’s sarcoma is commonly associated with acquired immune deficiency syndrome (AIDS)
Cutaneous squamous cell carcinoma[7]	SCC in situ (Bowen’s disease)	Patch Plaque	Erythematous Skin colored	Scaly	Variable	Fair-skinned individuals: sun-exposed areas In black individuals: legs, anus, and areas of chronic inflammation	Presence of dotted and/or glomerular vessels White to yellowish surface scales Red-yellowish background	Keratinocytic dysplasia of the epidermis No infiltration into dermis Pleomorphic keratinocytes Hyperchromatic nuclei	Slow growth over the years
	Invasive squamous cell carcinoma	Papule Plaque Nodule	Skin colored	Indurated + hyperkeratotic (well differentiated) Soft + ulceration (poorly differentiated)	0.5 to 1.5 cm	Fair-skinned individuals: sun-exposed areas In black individuals: legs, anus, and areas of chronic inflammation	White circles White structureless areas Masses of keratin Hairpin and linear-irregular vessels	Keratinocytic dysplasia of the epidermis No infiltration into dermis Pleomorphic keratinocytes Hyperchromatic nuclei	May be painful or pruritic
Keratoacanthoma[8]		Macule Papule May have telangiectasias	Skin-colored Mildly erythematous	Prominent keratinous core in the center of the nodule	1 to 2.5 cm	Sun-exposed areas Face, neck, hands, and arms	White circles Keratin Blood spots White structureless zones	Well-differentiated squamous epithelium Central keratin core Epidermal hyperplasia + large eosinophilic keratinocytes Dermal inflammatory infiltrate	Rapid growth (within weeks)
Merkel cell carcinoma[9]		Intracutaneous nodule	Shiny Flesh-colored or bluish-red	Firm	< 1 cm	Sun-exposed areas Head and neck Upper limbs and shoulder Lower limbs and hip Trunk	Milky red areas Linear Irregular vessels Polymorphous vessels	Uniform cells with large basophilic nuclei Single-cell necrosis Frequent mitoses Lymphovascular invasion Perineural invasion Epidermal involvement via pagetoid spread	Older individuals with light skin tones Rapidly growing
Basal cell carcinoma[10]	Nodular basal cell carcinoma	Papule	Flesh-colored	Small bump	Variable	Face	Focused, bright red, and branching arborizing vessels Loosely arranged blue-gray dots	Nest-like infiltration with basaloid cells	May have a “rolled” border
	Superficial basal cell carcinoma	Patch	Erythematous	Scaly	1 to > 10 cm	Sun-exposed areas Head (cheek and nose) Trunk	Superficial fine telangiectasia Shiny white to red, translucent or opaque structureless areas Multiple small erosions	Large, hyperchromatic, oval nuclei Minimal cytoplasm Small basaloid nodules	Higher incidence in men
	Sclerosing basal cell carcinoma (morpheaform)[11]	Papule Plaque	Flesh-colored Slightly erythematous	Firm Indurated Indistinct borders	Variable	Sun-exposed areas	Whitish background Few fine arborizing vessels Multiple brown dots Ulceration	Thin columns + small nodules Highly collagenized stroma	Expression of smooth muscle protein alpha-actin in tumor stroma
Prurigo nodules[12][13]		Dome-shaped nodule	Flesh-colored Erythematous Brown/black	Firm	Variable	Extensor surfaces of the arms and legs and on the trunk Upper back, abdomen, and sacrum	White “starburst pattern” surrounding red/brown/yellow crusts Erosions Hyperkeratosis	Thick and compact orthohyperkeratosis Irregular epidermal hyperplasia Focal parakeratosis with irregular acanthosis Nonspecific dermal infiltrate containing WBCs	Nodules range in number from few to hundreds Worsened by heat, sweating, or irritation from clothing
Melanoma[14]	Melanoma in situ (Lentigo Maligna)[15]	Macule	Variable (from light to dark brown, black, pink, red, or white)	Smooth	Around 1 cm	Sun-damaged skin of the head or neck	Asymmetric, pigmented follicular openings Gray angulated lines Gray areas, dots, and globules Circle within a circle	↑ atypical spindle shaped melanocytes Arranged in single cells or in small nests along the dermal-epidermal junction	Darkening of pigmentation, sharpening of borders, or emergence of nodular areas are signs of progression to lentigo maligna melanoma
	Lentigo maligna melanoma[16]	Macule	Brown/tan	Freckle-like	Variable	Chronically sun-damaged areas	Asymmetric, pigmented follicular openings Gray angulated lines Gray areas, dots, and globules Circle within a circle	“Star-burst giant cells” in epidermis “Swallow’s nest” sign along the dermal-epidermal junction Minimal cytoplasm Pale nucleus with small nucleoli	Usually in older individuals
	Superficial spreading melanoma[17]	Macule Plaque with irregular borders	Variably pigmented (red, blue, black, gray, and white)	Thin	1 mm to > 1 cm	Anywhere but usually: Back (men and women) Lower extremities (women)	Asymmetry of shape > 2 colors Asymmetry of structures	Asymmetric Poorly circumscribed Lack cellular maturation	Lateral (radial) growth before vertical (invasive) growth
	Nodular melanoma[18][19]	Polypoid nodule	Dark color	Lump	6mm to > 1 cm	Trunk Head Neck	Pigment network or pseudonetwork Aggregated brown or black globules Blue pigmentation within lesion Small dotted or comma vessels	Cells proliferate downwards through the skin Dermal growth in isolation or in association with an epidermal component	Two-thirds arise in normal skin, the rest in existing moles Rapidly enlarging
	Acral lentiginous melanoma[20]	Macule Patch	Dark brown to black	Raised areas Ulceration Bleeding	Variable	Palmar Plantar Subungual Mucosal surfaces	Parallel-ridge pattern Irregular diffuse pigmentation	Asymmetric proliferation of single melanocytes at dermoepidermal junction	Most common among dark skinned individuals
	Amelanotic melanoma[21]	Patch	Skin color	Slightly elevated borders	Around 6 mm	Sun-exposed areas	No melanin pigmentation Dotted vessels Linear irregular vessels		Lesions not pigmented since they don’t produce melanin
Common nevus[22][23]		Dome-shaped nodules	Hypopigmented	Smooth surface Terminal hairs often present	1 cm to > 20 cm	Sun-exposed areas above the waist	Comma-shaped or curved vessels Structureless light brown background Residual brown thick circles around the hair follicles	Multinucleated melanocytes Melanocytes diffusely infiltrate dermis	Also called Miescher nevus
Blue nevus[24]		Macule Papule	Blue	Smooth	Variable	Head and neck, Dorsal aspect of the distal extremities Sacral area	Structureless blue pigmentation Structureless blue and white or blue and brown on some occasions	Proliferation of dendritic, dermal, melanin-producing melanocytes	Also called Mongolian spots
Spitz nevus[25][26]	Nonpigmented Spitz nevus	Nodule	Pink	Smooth	< 1 cm	Cheek	Coiled vessels White network over a pink to reddish background		In children and adolescents
	Reed-like Spitz[27]	Papule	Heavily pigmented	Smooth	< 1 cm	Head and neck Upper and lower extremities	Structureless black to gray center Hypopigmented follicular openings Peripheral streaks Pseudopods Globules	Enlarged spindle melanocytes with polyangular form “Ground glass” cytoplasm	Most commonly develops in children, adolescents, and young adults.
Solar lentigo[28]		Multiple spots	Brown	Smooth	Around 5mm	Sun-exposed areas	Faint pigmented fingerprint structures Structureless pattern Light brown pseudonetwork with well-defined borders and a “moth-eaten” edge	↑ melanin deposition in keratinocytes ↑ linear arrangement of melanocytes at the dermal-epidermal junction	Associated with UV exposure and skin aging
Sebaceous hyperplasia[29]		Papule	Skin-colored to brownish	Umbilicated	2 – 6 mm	Forehead Nose Cheeks	Structureless yellow to whitish center surrounded by short linear “crown vessels“		Usually in middle-aged or older patients
Lichen planus-like keratosis[30]		Papule Plaque	Gray to brown	Prominent	Variable	Upper trunk	Shows a coarse or fine, gray to blue, granular pigmentation Diffuse brownish gray granules	Hypergranulosis Epidermal hyperplasia Superficial bandlike infiltrate Melanophages	Appearance depends on stage of evolution

Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1], Associate Editor(s)-in-Chief: Homa Najafi, M.D.[2]

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.

• Dermatofibroma is a common benign skin lesion that is seen in almost 3000 dermatophatology laboratory specimens per 100,000 ones. ^[1][2]

• As most of patients with dermatofibroma are asymptomatic, the worldwide incidence of dermatofibroma is unknown.^[2][3]

• Patients of all age groups may develop dermatofibroma. Although, it is more common in the 20s to 40s ages. ^[1][2][4]

• There is no racial predilection to dermatofibroma.^[1][3]

• Female are more commonly affected by dermatofibroma than male. The female to male ratio is approximately 2 to 1.^[1][3][5][4]

• The majority of [disease name] cases are reported in [geographical region].

• [Disease name] is a common/rare disease that tends to affect [patient population 1] and [patient population 2].

Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1], Associate Editor(s)-in-Chief: Homa Najafi, M.D.[2]

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

There are no established risk factors for dermatofibroma. Although, It is believed that minor trauma or a low-grade benign neoplasm can have role.^[1]

Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1];Associate Editor(s)-in-Chief: Homa Najafi, M.D.[2]

There is insufficient evidence to recommend routine screening for dermatofibroma.

There is insufficient evidence to recommend routine screening for dermatofibroma

Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1];Associate Editor(s)-in-Chief: Homa Najafi, M.D.[2]

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.

• Dermatofibroma usually develops in the third decade of life, and most of them are asymptomatic.^[1][2][3]

• Common complications of dermatofibroma are related to excisional removing of the lesion and include:^[4]
  • Bleeding
  • Infection
  • Scar

• Prognosis is generally excellent. Although, in very rare cases metastases are seen.^[5]