[Erythema elevatum diutinum. I. Electron microscopy of a case with extracellular cholesterosis (author's transl)]

[Cutaneous vasculitis]

Vasculitis is a term that refers to damage and inflammation of the walls of blood vessels of any size. The classification of types of cutaneous vasculitis continues to be a challenge, probably because of our lack of understanding of the etiology and pathogenesis of this condition. Changes in the vessel wall will be visible on microscopy and will enable the different clinical forms to be distinguished according to the caliber of affected vessels, the type of cell that predominates in the inflammatory infiltrate, or the presence of such key findings as extravascular granulomas. Skin manifestations (macules, papules, nodules, livedo reticularis, etc) correlate with the size of the vessel affected. The prognosis in cases of vasculitis with skin involvement will be determined by the presence or absence of extracutaneous disease. Systemic vasculitis shows a predilection for certain organs, such as the kidney or lung. The introduction of immunosuppressant drug treatments has led to evident improvement in survival rates for patients with vasculitis. This review covers practical aspects of the pathophysiology, histopathology, treatment, and differential diagnosis of the main clinical presentations of vasculitis with cutaneous involvement.

Ultrastructural study of chronic lesions of erythema elevatum diutinum: "extracellular cholesterosis" is a misnomer

Erythema elevatum diutinum (EED) is a rare disease of unknown origin that belongs to the spectrum of leukocytoclastic vasculitis. Chronic lesions of EED contain lipid deposits, for which the term extracellular cholesterosis has been coined. We studied a typical case of EED with long-standing lesions. Findings of electron microscopic examination revealed a heavy, exclusively intracellular lipid deposition that consisted of lipid droplets, myelin figures, and rare cholesterol clefts within histiocytes but also within epidermal keratinocytes, mast cells, pericytes, and lymphocytes. These findings are in keeping with the results of previous ultrastructural studies and suggest that the term extracellular cholesterosis is a misnomer; intracellular lipidosis would more accurately describe the lipid deposition.

Erythema elevatum diutinum in a patient with Crohn's disease

A possible association between erythema elevatum diutinum and Crohn's disease is described. To our knowledge, erythema elevation diutinum has never been reported in a patient with Crohn's disease, nor has the disorder been considered one of the cutaneous manifestations of inflammatory bowel disease. Erythema elevatum diutinum is believed to be mediated by the deposition of circulating immune complexes in the dermal perivascular spaces. Our patient showed clinical and histopathologic findings typical of both erythema elevatum diutinum and Crohn's disease. The patient also had a positive Raji cell assay, which demonstrates the presence of a circulating immune complex. Increased levels of circulating immune complexes have been found in patients with inflammatory bowel disease, and the gastrointestinal inflammation in Crohn's disease could lead to enhanced antigenic exposure and increased formation of immune complexes. We contend that inflammatory bowel disease may have contributed to the development of erythema elevatum diutinum in our patient.

Erythema elevatum diutinum: an ultrastructural case study

An electron microscopic study was made of a patient with erythema elevatum diutinum, a rare variant of cutaneous leukocytoclastic vasculitis. Biopsies were obtained from early evolving and late fibroproliferative lesions. Early lesions showed vasculitis and a massive dermal infiltrate composed mainly of neutrophils, histiocytes/macrophages and apparently increased Langerhans cells. Later lesions were characterized by a dense fibrosis with a proliferation of fibroblasts and myofibroblasts and a dermal infiltrate in which lymphocytes and histiocytes/macrophages predominated. Even in later lesions, dermal Langerhans cells were observed in great number. Langerhans cells may be involved in the evolution of this rare disease.

[Erythema elevatum diutinum. II. Immunoelectronmicroscopical study of leukocytoclastic vasculitis within the intracutaneous test reaction induced by streptococcal antigen (author's transl)]

A leukocytoclastic vasculitis was induced by intracutaneous injection of streptococcal antigen in a patient with erythema elevatum diutinum (E.e.d.). The immunoelectronmicroscopical demonstration of C3 was performed by use of the peroxidase-antiperoxidase multistep technique 24 h after the injection of the antigen. Deposits of C3 were found between endothelial cells, on the outer surface of endothelial cells, pericytes, and smooth muscle cells, as well as within the multilayered basal lamina of small vessels. Intact and disintegrating neutrophils accumulate within the vessel walls and in their surroundings. Necrosis and fibrin deposition are present in advanced stages. The findings demonstrate the sequence of events in leukocytoclastic vasculitis at the ultrastructural level. They also support the hypothesis that in E.e.d. an Arthus type reaction induced by bacterial antigens may be of pathogenetic significance.