Pseudoxanthoma Elasticum With Cutis Laxa-Like Features

Abstract

A 75-year-old Black woman with a history of hypertension and hyperlipidemia presented to the dermatology clinic for vulvar pruritus. Examination of her flexures revealed yellow, xanthoma-like papules coalescing into plaques. Prominent sagging of the skin (Figure) was noted in the axillae (left) and proximal inner thighs (right). The cutaneous changes began in early childhood, and her ophthalmologic history included retinal angioid streaks, glaucoma, and macular degeneration. Histologic examination of a punch biopsy from the vulva displayed fragmented and calcified elastic fibers throughout the reticular dermis, simulating a "bramble bush" pattern that is characteristic of pseudoxanthoma elasticum (PXE).Pseudoxanthoma elasticum is an autosomal recessive condition that predominantly affects the skin, eyes, and cardiovascular system. The gene variant, ABCC6, encodes an adenosine triphosphate-binding cassette transporter. The absence of functional ABCC6 is followed by reduced adenosine triphosphate secretion from hepatocytes, which leads to reduced plasma concentration of a mineralization inhibitor, inorganic pyrophosphate. 1 Because of the decreased antimineralization activity, there is subsequent calcification of elastic fibers in the mid to deep dermis, midsized arteries, and Bruch membrane of the eye. Pseudoxanthoma elasticum derives its name from the characteristic cutaneous findings, which bear some resemblance to xanthomas. Typically, in the first or second decade of life, small, yellowish, flat papules develop on the neck and flexural areas. 2 When the papules coalesce to form plaques, it creates the characteristic gooseflesh or plucked chicken skin appearance. The lateral neck is often affected first, with the antecubital and popliteal fossae, wrists, axillae, and groin being additional sites of possible involvement.In some cases, substantial sagging of the skin develops secondary to the loss of recoil because of the impaired function of the elastic fiber network, which can be typified as a secondary cutis laxa, and