From the Departments of Dermatology and Pathology, Mount Sinai Medical Center, New York, New York
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An 80-year-old African-American man, with a past medical history of childhood rheumatic fever, hypertension, coronary artery disease, unstable angina, and asbestosis, underwent cardiac catheterization 37 years ago for unstable angina. The postcatheterization course was complicated by a right brachial arterial thrombosis. A venous brachial bypass graft was placed, with vascular supply to the affected arm restored.Postbypass, the patient recovered full use of the arm, but suffered from persistent arm pain. Surgical sympathectomy was performed 1 year later. The patient has been pain-free since, but noted soon after sympathectomy, unilateral scaly dry skin, unilateral hypohidrosis of the axilla, and increased temperature sensitivity on the affected limb. In the 37 subsequent years, despite application of emollients, he reported no significant improvements or changes in the skin findings.The patient denied that other family members suffered from similar skin problems. He denied ever having atopy or other skin problems prior to the current episode.On physical examination, dry plate-like scales were seen on the dorsum of the right hand (Fig. 1A,B), right shoulder, and upper back, extending to the midline (Fig. 1C), in an area of distribution supplied by the injured nerves. Mild follicular prominence of the affected extensor arm was also seen as compared with the uninvolved arm (not shown).Bilateral 4-mm skin punch biopsies were obtained from the skin of the dorsum of the affected hand and unaffected control hand, in identical locations between the first and second digits. Tissue specimens were split and each sent in formalin and glutaraldehyde for routine histology and electron microscopic evaluation, respectively.For electron microscopy specimens, samples were fixed in 3% glutaraldehyde solution, postfixed in ferrocyanide osmium tetroxide, and then samples were dehydrated in graded series of ethanol and embedded in epoxy resin. Ultrathin sections were cut with a diamond knife on Sorval MT-2b ultramicrotome, mounted on copper grids, and examined in a JEOL EM 100 electron microscope.On routine microscopic evaluation, the affected skin demonstrated a thick hyperkeratotic and compact stratum corneum (Fig. 2), as compared with the loose basketweave appearance of the stratum comeum of the skin of the control hand (Fig. 3). A thin and hypodense granular layer with more diffuse and small keratohyaline granules was seen in the affected skin as compared with the control. The overall epidermal thickness, however, appeared unchanged.On electron microscopic evaluation, fewer, smaller, and more irregular keratohyaline granules in the granular layer of the affected skin were noted (Fig. 4), as compared with the larger, more numerous stellate, polygonal configuration of the control skin (Fig. 5). In an area of comparable epidermal thickness, the affected skin granular layer was approximately 1-1.5 cells thick, whereas the control skin granular layer was 2.5-3 cells thick. Strikingly, the cornified layer in the affected skin was thickened with an abnormally dense ultrastructure, as compared with the control skin (Fig. 6).