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Drug-induced porphyria-like disorders
Porphyria-like disorders have been reported as a reaction to some drugs. The reaction, histologically, is comparable to that seen in porphyria cutanea tarda. Tetracyclines have been associated with this type of
reaction (S13C24P22-1-3).
Green JJ, Manders SM: Pseudoporphyria. J Am Acad Dermatol 2001;44:100-8)
Acute Pityriasis lichenoides (with transformed lymphocytes)
The histologic patterns of
lesions of pityriasis lichenoides et varioliformis acuta can be accommodated in the category of lichenoid lymphocytic vasculitides. The patterns tend to be both spongiotic and lichenoid; some examples have psoriasiform qualities. In lesions of pityriasis lichenoides, the lymphoid infiltrates, particularly the epidermal components, may contain cells which morphologically qualify as transformed lymphocytes (so-called Lutzner’s cells) (S13C24P22-4-6, & S13C24aaP22aa-1 & 2). The patterns, in an example of pityriasis lichenoides showing a high
component of transformed lymphocytes, take on the attributes of lesions of lymphomatoid papulosis (type B). Some examples, over a period of time, may show, on multiple biopsies, cytologic and histologic
modulations which include the histologic parcels of PLVA, or the parcels of lymphomatoid papulosis, or even parcels of mycosis fungoides. In this temporal sequence, parcels of PLVA may be encountered after those of
lymphomatoid papulosis, or mycosis fungoides. The histologic features are not invariably manifested in irreversible, progressive steps; such lesions also tend to display remittent qualities.
Herpes virus infections
The reaction in herpes virus infection is cytopathic in an erythema multiforme-like pattern
(i.e., a lichenoid reaction). Included in the parcel, by which herpes virus infections are histologically defined, are: ballooning degeneration; cytolysis of both individual cells and clusters of cells (phenomena leading to the formation of reticulated, intra-epidermal vesicles); coagulation of both individual keratinocytes and groups of keratinocytes; and the patterns of a lichenoid lymphocytic vasculitis with a high component of histiocytes. The parcel finds specificity with the identification of intranuclear inclusions. Some lesions in the setting of post-herpes erythema multiforme are characterized by occasional keratinocytes that contain the characteristic intranuclear inclusions (S13C24aP22a-1-6).
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