Rash Judgement

Although this patient’s mother had diabetes, his fasting blood glucose was well within normal limits (71 mg/dL). Histologically NL displays sclerotic collagen and obliteration of the bundle pattern, with interstitial and palisaded granulomas that involve the subcutaneous tissue and dermis. Fat containing foam cells are often present.

Although our patient’s biopsy showed fat containing foam cells, it did not have the interstitial granulomas or the sclerotic collagen. In addition, the lack of diabetes makes this diagnosis less likely.6,7

Erythema elevatum diutinum (EED) is a rare type of leukocytoclastic vasculitis characterized by red, purple, brown, or yellow papules, plaques, or nodules. These lesions are usually distributed on the extensor surfaces of the body. The lesions are usually asymptomatic but can be associated occasionally with joint pain. Clinical studies show a preference for the extensor surfaces of the hands, the wrists, the elbows, the ankles, the Achilles’ tendons, the fingers, and the toes. The buttocks, the face, and the ears as well as the palms, the soles, the legs, the forearms, and the genitals may be involved; however, the trunk is usually spared. EED is a type of necrotizing vasculitis.

In its early stages, there are no specific histologic findings that can be used to single out the diagnosis of EED from other leukocytoclastic diseases. Although the distribution and lack of symptomatology in EED is reminiscent of our patient, this patient’s lesions were more often found in the flexural areas rather than extensors. In addition, there was no necrotizing vasculitis on histology, which precludes this rare diagnosis of EED.8

Xanthoma disseminatum (XD) is a rare, benign, proliferative disorder in children and young adults characterized by xanthomatous lesions especially in the flexural folds and eyelids. Although it sounds like a disorder of lipid metabolism, it is actually a histiocytic disorder that is not associated with lipoprotein abnormalities and patients are normolipemic. Histologically, it shows mononuclear phagocyte proliferation with Touton giant cells and CD68 positivity on immunophenotyping. It is unlikely that this patient has XD despite the appropriate clinical presentation because histologically all that is found are foam cells. In addition, the patient had a definite lipoprotein abnormality while XD patients are normolipemic.9 TH

References

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3. Parker F. Xanthomas and hyperlipidemias. J Am Acad Dermatol. 1985 Jul;13 (1):1-30.
4. Young RJ, 3rd, Gilson RT, Yanase D, et al. Cutaneous sarcoidosis. Int J Dermatol. 2001;40:249-253.
5. English JC, Patel PJ, Greer KE. Sarcoidosis. J Am Acad Dermatol. 2001;44:725-743: quiz 744-746.
6. Fitzpatrick TB, Johnson R, Wolff K, et al. Genetic, metabolic, endocrine and nutritional diseases. Color Atlas and Synopsis of Clinical Dermatology, Common and Serious Diseases. New York: McGraw-Hill; 2001:415-416.
7. Lowitt MH, Dover JS. Necrobiosis lipoidica. J Am Acad Dermatol. 1991; 25:735-748.
8. Yiannias JA, el-Azhary RA, Gibson LE. Erythema elevatum diutinum: a clinical and histopathologic study of 13 patients. J Am Acad Dermatol 1992 Jan;26(1):38-44.
9. Alexander AS, Turner R, Uniate L, et al. Xanthoma disseminatum: a case report and literature review. Br J Radiol 2005 Feb;78(926):153-157.