Angiokeratomas are a group of vascular ectasias that involve the papillary dermis and may produce papillomatosis, acanthosis, and hyperkeratosis of the epidermis.[1] Several clinical variants of angiokeratomas exist; angiokeratoma circumscriptum is a specific type and is the rarest of the other types of angiokeratomas. Overall, eight types of angiokeratomas have been described in the literature. Some groups of angiokeratomas are deemed to be more alarming than others. The first reported case dates back to 1889 when Doctor Vittorio Mibelli recorded what is now known as angiokeratoma Mibelli-type on the fingers and the toes. Doctor Johann Fabry first described angiokeratoma circumscriptum in 1915 as a localized lesion on a lower extremity or the trunk. In addition, a rare manifestation of angiokeratoma circumscriptum naeviforme, with appearance on the neck, has been documented. As few as only 100 cases of angiokeratoma circumscriptum have been worldwide until 2006. Angiokeratoma lesions are of clinical importance because, often being dark purple or black, they may clinically mimic a malignant melanoma.[2, 3]
In many cases, angiokeratoma lesions are present at birth, but they may also appear in childhood or adulthood. Angiokeratoma circumscriptum has been reported to coexist with angiokeratoma of Fordyce[4] (found on the scrotum) and caviar spots (angiokeratomas of the tongue).[5] Other clinical associations include its occurrence with Cobb syndrome, Klippel-Trenaunay syndrome, nevus flammeus, cavernous hemangiomas, hemangiectatic hypertrophy,[6] angiokeratoma corporis diffusum,[7] and traumatic arteriovenous fistulas. Angiokeratoma circumscriptum has also been called angiokeratoma corporis naeviform and may be best classified as a type of capillary malformation.[8, 9]
Noted by Imperial and Helwig in 1967, angiokeratomas are actually telangiectasias of already-existing vessels rather than angiomas.[10] How angiokeratoma circumscriptum develops has not yet been elucidated. A few proposed ideas include congenital development, pregnancy, trauma, subcutaneous hematomas, and tissue asphyxia.
Interestingly, lymphangioma circumscriptum, an entity that is microscopically similar to angiokeratoma circumscriptum, has been reported to occur in a setting of damaged deep lymphatic vessels. Unlike angiokeratoma of Mibelli or angiokeratoma corporis diffusum (Fabry disease), no pattern of inheritance or associated enzyme defect has been found for angiokeratoma circumscriptum. Overall, altered hemodynamics (typically caused by trauma) appear to produce telangiectatic vessels of the papillary dermis with an overlying reactive hyperkeratosis to the epidermis.[11]
The cause of angiokeratoma circumscriptum is unknown. Several causal factors, such as congenital development, pregnancy, trauma,[12] subcutaneous hematomas, and tissue asphyxia, have all been proposed (see Pathophysiology).
The frequency of angiokeratoma circumscriptum in the United States is unknown, yet it has been reported worldwide to occur in 16% of the population. However, the condition is probably more common than what the relatively few cases in the literature indicate. Because it has no associated systemic morbidity, most cases remain clinically innocuous and go unreported. The majority of the population to develop angiokeratoma circumscriptum are males; however, it occurs in females as well.[13]
Race
No ethnic predilection has been observed or reported to date.
Sex
Males are affected more commonly than females.
Age
Angiokeratoma circumscriptum may be either congenital or acquired. Lesions are commonly present at birth, but development in early childhood and adulthood has been documented.
Angiokeratoma circumscriptum lesions are asymptomatic benign vascular malformations that require no treatment. Laser ablation has proven highly effective and may offer the best cosmetic outcome.
Angiokeratoma circumscriptum is a benign vessel ectasia involving the papillary dermis. No deaths from this entity have been reported. However, because it may clinically mimic a melanoma, morbidity may arise from attempts to render treatment for a melanoma before histologic verification is given. Furthermore, because angiokeratomata are vascular lesions, recurrent bleeding can occur. Life-threatening bleeding is not a concern because the affected vascular spaces are small. However, excessive bleeding has been noted when trauma occurs to the lesions.[13]
Angiokeratoma circumscriptum lesions are most commonly found on the lower extremities as an asymptomatic solitary papule or plaque, but they can also be found virtually anywhere, with dominance on the legs, upper extremities, and trunk.[14] One incidence of angiokeratoma circumscriptum involved an asymmetrical distribution in a systematized bandlike, segmental arrangement in the trunk, legs, and face.[15]
Several reports have noted angiokeratoma circumscriptum appearing on the ventral and, less commonly, the dorsal surface of the tongue.[16, 17, 18]
Occasionally, multiple lesions develop, usually after adolescence.
Patients may present with a rapid darkening or a change of the lesion.
Sometimes, patients may be specifically concerned about the possibility of melanoma, given the dark purple or black color of the lesion.[19] See the images below.
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A hyperkeratotic, asymmetric, variably pigmented, black 3 X 4-mm papule was found on the upper right medial part of the arm of this 18-year-old woman,....
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Close-up view of an asymmetric black angiokeratoma mimicking a melanoma.
The primary lesions of angiokeratoma consist of elevated, hyperkeratotic, dark red to purple or black, slightly compressible papules. Small nodules or plaques can also be seen. Sometimes, a linear distribution (with bands or streaks) of papules develops. A rough hyperkeratotic scale is often found over the surface and the edges of these papules due to epithelial hyperplasia and hyperkeratosis.
The lesions often have irregular borders and associated pigmentation, which is mostly attributable to intraepidermal hemorrhage or associated hemosiderin pigment deposition in the dermis. If excoriated or traumatized, angiokeratomas may present with epithelial erosion and bleeding.
When compressed with a glass slide, the dark purple or black color often blanches to red.
No laboratory studies are required to identify or diagnose this entity. However, further microscopic evaluations may be conducted and reveal hyperkeratosis, acanthosis, and pervasive papillary dermal vascular proliferation.[3]
Imaging studies are not usually indicated in the evaluation of this superficial cutaneous vascular lesion. If multiple grouped angiokeratomas are found overlying the spine in a newborn or an infant, an MRI of the spine may be prudent to exclude spinal dysraphism or Cobb syndrome.
The laboratory evaluation that confirms the diagnosis is a biopsy. Depending upon the size, shape, and estimated depth of the lesion, a shave or punch biopsy is usually performed. The biopsy result will eliminate melanoma from the clinical differential.
The histopathologic features of angiokeratoma circumscriptum are similar to those seen in other clinical types of angiokeratomas (eg, Mibelli type, Fordyce type, Fabry disease). The process has an exophytic profile, with numerous ectatic thin-walled vascular channels that expand the papillary dermis. Thrombosis of these vessels is common and is responsible for the clinical mimicry of melanoma. The overlying epidermis encompasses the vascular spaces, often with a collarette, and displays variable degrees of acanthosis and hyperkeratosis. The hyperkeratotic scale may be orthokeratotic and parakeratotic. The dermal connective tissue is usually not involved, but it may contain a few siderophages.
View Image
Low-magnification histologic view reveals some hyperkeratosis and acanthosis with rete ridges surrounding dilated vascular channels in the papillary d....
View Image
This mid-power histologic view reveals dilated vessels in the papillary and upper reticular dermis. The vessels are packed with red blood cells; this ....
View Image
This high-power histologic view reveals some hyperkeratosis and acanthosis with rete ridges surrounding dilated vascular channels in the papillary der....
The lesions of Fabry disease may be differentiated from other forms of angiokeratoma because lipid-containing cytoplasmic vacuoles can sometimes be detected in endothelial cells, fibroblasts, and pericytes.
Lymphangioma circumscriptum, perhaps the most similar to angiokeratoma circumscriptum, is a clinically distinctive vascular malformation consisting of dilated lymphatic channels arrayed within the papillary dermis. Sometimes, these lymphangiectatic spaces are filled with serosanguineous lymph fluid, but hemorrhage into the spaces can render them microscopically indistinguishable from those of angiokeratomas. At present, no immunoperoxidase markers allow definitive distinction of blood vascular endothelium from lymphatic vascular endothelium.
Verrucous hemangioma is a descriptive term that is used to classify conventional hemangiomas in which associated verrucous epidermal changes are present. Although the superficial changes in a verrucous hemangioma can be identical to those of an angiokeratoma, usually a greater degree of depth and vascular proliferation are evident in the hemangioma. In short, angiokeratomas are typically confined to the papillary dermis, whereas verrucous hemangiomas involve all levels of the dermis and may extend to involve the subcutis.
Other vascular lesions can be associated with capillary dilatation. The diverse list of diseases includes entities such as generalized essential telangiectasia, unilateral nevoid telangiectasia, angioma serpiginosa, and Osler-Weber-Rendu disease. These syndromes lack the overlying epidermal changes seen in angiokeratomas; therefore, they are not usually included in the pathologic differential diagnosis of angiokeratoma.
Angiokeratoma circumscriptum lesions are asymptomatic benign vascular malformations that require no treatment. Nevertheless, surgical treatment is often rendered for cosmesis or because of clinical concern regarding the possibility of melanoma. Either ablation (after a firm diagnosis is established) or excision of the lesions (when the diagnosis is uncertain) can be performed. Depending on the size and the location of the angiokeratoma, simple excision may be the treatment of choice. Small lesions may also be treated with diathermy, curettage, and cautery.
Laser ablation
Laser ablation has proven highly effective and may offer the best cosmetic outcome. Specifically, the argon laser has been reported to effectively eliminate angiokeratomas, although associated scarring and posttreatment hypopigmentation are risks.[23, 24]
One treatment approach is to initiate treatment with an erbium or carbon dioxide laser to remove the hyperkeratotic-acanthotic epidermis, followed by the use of a laser that targets hemoglobin, such as the flash pump dye, KTP, or 880-nm diode laser.[25, 26, 27]
Alternatively, an erbium or carbon dioxide laser may be used alone, although this approach may cause significant collateral thermal damage to the dermis and, thus, significant scarring may ensue.
A KTP laser or 800-nm diode laser may also be used alone, although multiple procedures may be needed for adequate treatment, depending on the underlying vessel diameter and the overlying epidermal thickness. Because of its wavelength and deeper dermal penetration, the 800-nm diode laser may be most useful for blue-black angiokeratoma circumscriptum or those with thrombosed vessels.
The KTP laser destroys vascular targets and is relatively specific for cutaneous blood vessels; therefore, it is ideal for the treatment of cutaneous vascular lesions. It causes less purpura than other laser systems, and patients are able to return to work immediately after treatment to the face. A typical setting for a 532-nm KTP laser for trunk angiokeratomas might be a fluence of 16-20 J/cm2 with a pulse duration of 30-50 milliseconds and a spot size of 4 mm.
Other ablative therapies
Other superficial ablative therapies, such as cryotherapy, may also be effectively used to treat superficial angiokeratomas. Recurrence of the lesion after surgical excision or ablation should bring into question the original diagnosis, and histopathologic examination of the lesions should be incorporated into the evaluation of the process in such an event.
William P Baugh, MD, Assistant Clinical Professor of Dermatology, Western University of Health Sciences; Medical Director, Full Spectrum Dermatology; Consulting Staff, Department of Dermatology, St Jude Medical Center
Disclosure: Nothing to disclose.
Coauthor(s)
Cynthia L Chen, DO, DO, Intern, Pacific Hospital of Long Beach, California
Disclosure: Nothing to disclose.
Natalie Ana Baugh, California State University, Long Beach
Disclosure: Nothing to disclose.
Specialty Editors
Michael J Wells, MD, FAAD, Dermatologic/Mohs Surgeon, The Surgery Center at Plano Dermatology
Disclosure: Nothing to disclose.
Rosalie Elenitsas, MD, Herman Beerman Professor of Dermatology, University of Pennsylvania School of Medicine; Director, Penn Cutaneous Pathology Services, Department of Dermatology, University of Pennsylvania Health System
Disclosure: Received royalty from Lippincott Williams Wilkins for textbook editor.
Chief Editor
William D James, MD, Paul R Gross Professor of Dermatology, Vice-Chairman, Residency Program Director, Department of Dermatology, University of Pennsylvania School of Medicine
Disclosure: Received income in an amount equal to or greater than $250 from: Elsevier; WebMD.
Additional Contributors
Timothy McCalmont, MD, Director, UCSF Dermatopathology Service, Professor of Clinical Pathology and Dermatology, Departments of Pathology and Dermatology, University of California at San Francisco; Editor-in-Chief, Journal of Cutaneous Pathology
Disclosure: Received consulting fee from Apsara for independent contractor.
A hyperkeratotic, asymmetric, variably pigmented, black 3 X 4-mm papule was found on the upper right medial part of the arm of this 18-year-old woman, who was concerned about melanoma. The histologic analysis revealed a thrombosed angiokeratoma circumscriptum.
Close-up view of an asymmetric black angiokeratoma mimicking a melanoma.
Low-magnification histologic view reveals some hyperkeratosis and acanthosis with rete ridges surrounding dilated vascular channels in the papillary dermis.
This mid-power histologic view reveals dilated vessels in the papillary and upper reticular dermis. The vessels are packed with red blood cells; this finding is suggestive of vessel thrombosis.
This high-power histologic view reveals some hyperkeratosis and acanthosis with rete ridges surrounding dilated vascular channels in the papillary dermis. Dilated vessels in the papillary and upper reticular dermis are observed. The vessels are packed with red blood cells; this finding is suggestive of vessel thrombosis. A normal-appearing vascular endothelium is found. No evidence of a melanocytic lesion is present.
A hyperkeratotic, asymmetric, variably pigmented, black 3 X 4-mm papule was found on the upper right medial part of the arm of this 18-year-old woman, who was concerned about melanoma. The histologic analysis revealed a thrombosed angiokeratoma circumscriptum.
Close-up view of an asymmetric black angiokeratoma mimicking a melanoma.
Low-magnification histologic view reveals some hyperkeratosis and acanthosis with rete ridges surrounding dilated vascular channels in the papillary dermis.
This mid-power histologic view reveals dilated vessels in the papillary and upper reticular dermis. The vessels are packed with red blood cells; this finding is suggestive of vessel thrombosis.
This high-power histologic view reveals some hyperkeratosis and acanthosis with rete ridges surrounding dilated vascular channels in the papillary dermis. Dilated vessels in the papillary and upper reticular dermis are observed. The vessels are packed with red blood cells; this finding is suggestive of vessel thrombosis. A normal-appearing vascular endothelium is found. No evidence of a melanocytic lesion is present.
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