Lichen planus has characteristic clinical and histopathological features Which make the diagnosis relatively easy. In a previous study (1), the microscopic findings in lichen planus were considered to be more than 90 per cent diagnostic. METHOD One hundred cases clinically accepted as lichen planus were studied. A biopsy specimen from each patient was fixed in 5 percent neutral formalin, and was stained with hematoxylin eosin. RE5ULT5 Although there was some variability in histologic features,

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... ll of the sections examined were sufficiently characteristic of lichen planus to verify the clinical impression. A summary of the histopathologic findings is presented in Chart I. Paraleerat osis was present in thirteen sections. In twelve, the areas of parakeratosis were small and irregularly spread over the surface; otherwise, the keratinization was regular. The surface of one section revealed crusting. The characteristic hyperkeratosis without parakeratosis of lichen planus was present in the other 87 specimens. Beading of the granular layer was present in 93 sections and absent in seven. Acanthosis of several forms was recognized. In nine sections, the malpighian layer was increased to form an epithelial papule (Mc-Carthy) (2). Twenty-three sections revealed acanthotic epithelial ridges with epidermis of normal thickness between the ridges. Epidermal atrophy was apparent in same areas in forty-seven sections. In twenty-one sections neither atrophy nor hypertrophy of the epidermis was pronounced. Liquefaction degeneration is characterized basal-cell layer of the epidermis with vacualization of variable number of basal cells, a loss of the usual morphology of the basal cells, and in many cases, also of the lower rete cells. This may result in loss of cohesiveness between the individual basal cells, and between the epidermis and the dermis, and was present in at least a portion of each biopsy specimen. Max Joseph Spaces or small blisters underlying several or mare contiguous basal cells were apparent in seventeen of the one hundred sections. In many of such spaces a serous or faintly cosinophilic fluid was deposited and at times a few mononuclear cells were present. In several of the sections an enlarged space or subepidermal vesicle was seen. Eosinophilic bodies.-The term eosinophilic bodies in lichen planus is applied to the colloid or hyalin bodies which may be present in the rete cells as deeply staining intracellular material in sections stained with hemotoxylin-eosin. The colloid material usually fills the cell and the nuclei either disappear or are shrunken and pyknotic. Eosinophilic bodies were present within the epidermis of thirty-seven sections ( Fig. 2 and 3) . These bodies were usually present in the mid-and lower rete and were interspersed between apparently normal epithelial cells. Some were slightly smaller than the normal epithelial cells. Often an intracellular clear area, which appeared to be due to shrinkage, surrounded a completely homogenized mass which stained deeply eosinophilic with hemotoxylin-eosin. Many such bodies contained basophilic dots or masses which resembled pyknotic or fragmented nuclei. Dermal infiltrate appeared as a distinct band, closely applied to the epidermis, and was present in all one hundred sections. Most of the cells were small, mononuclear lymphocytic cells. In eighty-two sections some epithelial cells were observed, and in eighteen many epithelial cells were seen within the infiltrate. Fibrocytes were recognized in five, and three sections contained many scattered plasma cells. In one section some giant cells were seen, and in one, some polymorphonuclears were mixed with the lymphocytes. Mild perivascular cuffing of small mononuclear 143