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Cutaneous pseudolymphoma is a term used to describe skin lesions that bear a clinical and/or histopathologic resemblance to lymphoma. Over the years, a wide variety of designations have been included in this category. Some of these represent outdated synonyms, some refer to variants of the same entity, and some are misnomers for diseases now recognized to be true lymphomas. The relevant entities that are discussed in this and other chapters can be organized into several distinct disorders based on their lymphoid subset composition, pattern of cutaneous infiltration, and associated clinical findings (Table 146-1).
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Cutaneous lymphoid hyperplasia (CLH) has a worldwide distribution and affects all races and ethnic groups. It occurs in both adults and children. Females are more commonly affected than males.
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Etiology and Pathogenesis
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CLH is characterized by a relatively dense lymphoid infiltrate, centered in the reticular dermis, which is usually B-cell rich and may resemble lymphoma clinically and/or histopathologically. Many terms are used to refer to this type of pseudolymphoma, including Spiegler–Fendt sarcoid, lymphocytoma cutis, lymphadenosis benigna cutis, and cutaneous lymphoplasia. Cutaneous lymphoid hyperplasia is the preferred term because it accurately describes the underlying pathophysiology of the lesion and is unlikely to be confused with terms used to describe various forms of cutaneous lymphoma.1–6
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In most cases, CLH is idiopathic; however, some lesions are associated with exposure to foreign antigens from arthropods (bites, stings, infestations), infections (herpes zoster, Borrelia burgdorferi, Helicobacter pylori), tattoos, acupuncture, trauma, gold jewelry, vaccinations, hyposensitization injections, or medications (Figs. 146-1, ...