Angiokeratoma Circumscriptum Workup

Updated: Oct 17, 2019
  • Author: William P Baugh, MD; Chief Editor: William D James, MD  more...
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Workup

Laboratory Studies

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]

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Imaging Studies

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.

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Procedures

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.

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Histologic Findings

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.

Low-magnification histologic view reveals some hyp 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 ves 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 hyper 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.

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.

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