Melanonychia siriola refers fo a pigmented (lan-brown-blafk) streak due to the presence of melanin in the nail plate and/or nail bed. The streak is caused by a focal increase of the number and/or function of normal appearing or of abnormal melanocytes. PigmeiKed bands, often involving multiple digits, are prevalent in individuals of the more deeply pigmented races and, in them, are considered to be "normal" in the vast majority of instances.Among the causes of melanonychia striata are neoplasias inchiding naevocytic naevi. atypical nielanocytic hyperplasia, and acral lentiginous melanoma. A series of cases is presented (o illustrate these oncological lesions. Until further knowledge is gained, surgical removal is recommended for those lesions resulting in melanonychia striata which fall into the neoplasdc group.It is concluded thai much more study is required to determine the biological significance, natural history, and outeome of these periungual melanocytic neoplasias.

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The histologic fate of an injectable form of type I bovine dermal collagen (Zyderm Collagen Implant, ZCI) in the pig dermis and subcutaneous tissue has been studied. Biopsies were taken sequentially and analyzed by hematoxylin and eosin (H&E) and Weigert's stain, by birefringence, by direct immunofluorescence (using a highly specific rabbit anti-Zyderm antibody), and by electron microscopy. The implant material was found to stimulate a host response resulting in implant degradation and replacement by newly generated host collagen.

HIV-infected patients can present with a pruritic, widespread disorder, often with pigment changes characterized by an atypical cutaneous lymphocytic infiltrate. This clinicopathologic disorder is a rare, reactive inflammatory condition which generally occurs in late stage HIV infection and rarely progresses to frank lymphoma.