MEDSCAPE HEMANGIOMA HOBNAIL.docx

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Targetoid Hemosiderotic Hemangioma

sumber :http://emedicine.medscape.com

Pathophysiology

The exact pathogenesis of targetoid hemosiderotic hemangioma (THH) is unknown, but some

authorities have postulated trauma to lymphatic vessels with development of lymphatic-

vascular microshunts play a key role in the pathogenesis of the defining features of targetoid

hemosiderotic hemangioma: dilated vascular spaces with hobnailed endothelial cells,

extravasation of red blood cells and hemosiderin deposits, fibrosis, and inflammation. Recent

studies have demonstrated that THH vessels are lymphatic in origin. The absence of Wilms

tumor 1 antigen expression supports a malformative rather than neoplastic etiology.[3, 4]

One theory states that targetoid hemosiderotic hemangioma is the result of trauma to a

preexisting hemangioma that subsequently is altered by thrombosis and recanalization;

however, reports fail to document a preexisting vascular tumor, such as lobular capillary

hemangioma or congenital vascular malformation, in the 100-plus cases reported to date.

A second theory suggests that trauma disrupts vasomotor enervation. This leads to an

inability to regulate blood flow and results in progressive vascular ectasia, which is

characteristic of targetoid hemosiderotic hemangioma. This scenario also has been postulated

as a mechanism contributing to the development of acquired port-wine stains. No

documented aberration in nerve fiber density in targetoid hemosiderotic hemangioma exists

to support this theory.

A third theory proposes that trauma obstructs or destroys draining lymphatics or veins. This

leads to proximal compensatory vasodilation and subsequent formation of a

hemolymphangioma. This theory is supported by microscopic findings, such as fibrosis and

inflammation (scar formation), extravasation of red blood cells and hemosiderin deposition

(bruising), telangiectases (secondary to venous bed blockage or destruction), and

lymphangiectases (consequence of destruction of lymphatic drainage). Expression of vascular

endothelial cell growth factor receptor 3 (VEGFR-3) and D2-40, lymphatic endothelial cell

markers, by targetoid hemosiderotic hemangioma endothelial cells confirms the primarily

lymphatic origin of targetoid hemosiderotic hemangioma.[5]

These studies examining vessel origin have revealed microshunts between lymphatic

channels and small blood vessels that may well explain many of the histologic features of
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targetoid hemosiderotic hemangioma, such as aneurysmatic microstructures

(telangiectases/lymphangiectases) and erythrocytes within histologically apparent lymphatic

spaces. The hemolymphatic nature of targetoid hemosiderotic hemangioma would also

explain the clinicopathologic overlap with solitary angiokeratoma, an acquired vascular

tumor that is also suspected to arise secondary to trauma and is characterized by superficial

dermal dilated vessels (telangiectases).

No clear indication exists that targetoid hemosiderotic hemangioma is a true neoplastic

process. Incomplete biopsies and complete excisions typically have not been followed by

recurrence. To the contrary, reports of waxing and waning lesions suggest a reactive nature.

In some cases, this may be the result of the hormonal influence on vasomotor stability that

occurs during pregnancy and the menstrual cycle.

[6, 7] [8, 9]

Spontaneous resolution can befollowed by recurrence and is not associated with any scarring.[4, 10, 11]

Epidemiology

Sex

Males appear to be affected more frequently by targetoid hemosiderotic hemangioma than

females (male-to-female ratio of 1.4:1). Episodically changing targetoid hemosiderotic

hemangiomas have been described more frequently in females than in males.

Age

In targetoid hemosiderotic hemangioma patient age varies from 5-72 years, and most patients

present during their 20s and 30s.

History

Targetoid hemosiderotic hemangioma (THH) (hobnail hemangioma) is a benign vascular

tumor that typically manifests as a small, single lesion on the extremity or trunk of a young to

middle-aged adult. It has a variable clinical appearance, but most can be described as annular

lesions with a central violaceous papule surrounded by an eccentric ecchymotic ring that can

exhibit a targetoid appearance. The wide variation in clinical appearance and variegation of

color explains why these lesions can be mistaken for a hemangioma, melanocytic nevus, or

melanoma.


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Lesions generally are asymptomatic, but they may be painful, change color, increase in size,

or exhibit cyclical or episodic change. These changes typically are described as enlargement

with deepening of color hue, followed by decrease in size and diminished color intensity.

Cases with cyclical morphologic changes have been correlated with hormonal events of the

menstrual cycle, although it should be noted that some of these cases have not been

documented rigorously from a microscopic standpoint and can represent other processes such

as endometriosis.

Spontaneous regression without scarring has been described with recurrence in 1 of 2 cases

reported.[10, 11]

Physical

Classic targetoid hemosiderotic hemangioma (THH) manifests as a solitary pigmented lesion

consisting of a central, small (2-3 mm), violaceous papule (the bull's-eye) surrounded by an

erythematous-to-ecchymotic ring or halo. Overall dimensions can vary from 1-2 cm. Note the

image below.

Lesions typically affect the trunk or the extremities (lower > upper). Head ,[1] neck, and oral

involvement and the occurrence of 2 simultaneous lesions have been reported.

The typical clinical morphology consists of a macule, papule, or targetlike lesion. Targetoid

lesions are more likely to be seen in larger and symptomatic targetoid hemosiderotic

hemangiomas, while macular targetoid hemosiderotic hemangioma lesions typically are

small.

A central papule is common but is not present universally. The peripheral halo can wax and

wane in both size and color as a result of the degree of erythrocyte extravasation and

hemosiderin deposition. The predominant color is brown or tan; a few lesions exhibit a black,

violaceous, or grayish appearance.

Variability in clinical morphology results in a wide variety of clinical diagnoses, including

considerations such as KS, melanocytic nevus, or melanoma.

Dermoscopic examination reveals sharply demarcated red or reddish-blue round and oval

structures. Intermixed with these structures are smaller, pale pink, round structures found

among a diffuse pink-white pigmentation. These 2 regions are thought to correspond to

ecstatic thin-walled vessels of the papillary dermis and slitlike vascular spaces of the reticular


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dermis, respectively. A few sharply demarcated black macules representing hemorrhagic

crusts can also be found.[7]

If serially monitored dermoscopically, a violaceous, expanding ring can be found surrounding

the central vascular dilations. This ring becomes an erythematous or hypopigmented halo that

eventually fades. Fine delicate pigmentation corresponding to hemosiderin can be found in

this halo region.[11, 12, 13]

Pigment networks (ie, brown or black globules or dots) typical of melanocytic proliferations

are not found in targetoid hemosiderotic hemangiomas.

Causes

Trauma is the only known predisposing factor for targetoid hemosiderotic hemangioma

(THH).[14, 15] Reports of targetoid hemosiderotic hemangioma secondary to irritation from a

belt and arthropod assaults exist. Histologic findings of foreign body giant cell reaction in a

few cases points to a preceding injury. Episodic changes of enlarging and diminishing

hemorrhagic/hemosiderotic halo also implicate recurring trauma or vessel fragility.

Hormones can influence clinical morphology, resulting in the cyclic changes of waxing and

waning diameter and peripheral color. Estrogen is believed to mediate pregnancy-related

vessel changes, such as spider telangiectases, and estrogen is known to promote vascular

permeability and fragility, venous distensibility, increased blood flow, and vasomotor

instability.[16] In targetoid hemosiderotic hemangioma, fluctuating estrogen levels may result

in vessel instability and leakage. Of note, hormonal receptors have not been identified

histologically in lesions of targetoid hemosiderotic hemangioma noted to cyclically change

with the menstrual cycle.

Differential Diagnoses

Acquired Progressive Lymphangioma Angiokeratoma Circumscriptum Dermatofibroma Kaposi Sarcoma Lymphangioma Malignant Melanoma Nevi, Melanocytic

Targetoid hemosiderotic nevus Venous Lakes
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Laboratory Studies

Laboratory testing is not necessary in targetoid hemosiderotic hemangioma (THH) once a

firm histopathologic diagnosis has been made. Occasionally, testing for human herpesvirus 8

and the human immunodeficiency virus is relevant, if the clinical and pathologic evaluation

of the lesion has raised the issue of Kaposi sarcoma (KS) in the differential diagnosis.[8]

Medical Care

Medical care is not necessary for targetoid hemosiderotic hemangioma (THH), a benign

lesion.

Medication Summary

No applicable medical therapy exists at this time

Further Inpatient Care

No inpatient care is required for targetoid hemosiderotic hemangioma (THH).

Further Outpatient Care

No further outpatient care is applicable to the evaluation or care of targetoid hemosiderotic

hemangioma.

Prognosis

With incisional biopsy or complete excision, the prognosis is excellent, as expected in

association with a benign lesion. Reports in the literature clearly indicate that targetoid

hemosiderotic hemangioma does not recur, does not invade locally or become locally

destructive, and does not spread to other body sites

Rarely, spontaneous resolution can occur, but a risk for recurrence exists.[10, 11]

Patient Education

Because targetoid hemosiderotic hemangioma can mimic malignant skin tumors, advise

patients who have had a targetoid hemosiderotic hemangioma to seek medicodermatologic

consultation should they find another similar lesion on self-examination.

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