Angiomatosis with angiokeratoma-like features in children: A light microscopic and immunophenotypic examination of four cases

We have identified three patients with an initial clinical or biopsy diagno sis of angiokeratoma, all of whom were found to have a more extensive vascu lar lesion within the surgical excision. A fourth patient with identical hi stologic findings had no specified clinical diagnosis and his first procedu re was excisional. The patients ranged in age from 7 to 16 years, and the l esions were located on the buttock, thigh, calf, and foot. Macroscopic appe arances included mildly keratotic pink-red or blue-grey macules (three case s) and pink macules with focal ulceration (one case). In three of the four cases, a shave biopsy diagnosis of angiokeratoma had been made, and the ext ensive and deeply infiltrative nature of the vascular proliferation was rec ognized only at subsequent resection, at which point angiomatosis was diagn osed. In the fourth case, excisional biopsy was attempted at presentation, and the superficial morphology was angiokeratoma-like, but the vascular pro liferation was present in the deep subcutaneous fat. CD31 and CD34 reactivi ty was present in the superficial and deep vessels in all cases, and lesion al vessels were rimmed by a bland population of smooth muscle actin positiv e pericytes, findings that differentiate these cases from angiokeratoma, wh ich has previously been reported to be CD34 negative. We conclude that the dilated vascular spaces that typify angiokeratoma may also be seen overlyin g a deep vasoformative process that is not amenable to resection, and sugge st that caution should be exercised in evaluating small biopsies with angio keratoma-like appearance.