Linear lichen planopilaris of the trunk: first report of a case.

BACKGROUND

Lichen planopilaris (LPP) is believed to be a follicular variant of lichen planus that affects pilosebaceous units, mainly of the scalp. An extremely rare variant of LPP is a linear form, which follows the lines of Blaschko. Of the five previously documented cases of linear LPP, all were limited to the face.

OBJECTIVE

We report the case of a 34-year-old male who presented with a nonpruritic eruption on the trunk consisting of erythematous, keratotic, folliculocentric papules following Blaschko's lines.

RESULTS

Biopsy revealed lichenoid and interface dermatitis involving the basilar epidermis and hair follicles, as well as apoptotic keratinocytes, consistent with LPP.

CONCLUSION

This represents the first documented case of LPP, following the Blaschko's lines, in a nonfacial distribution.