Association of the cornoid lamella with the follicular infundibulum and the acrosyringium: A histological analysis

Abstract

Background: The classical histological feature of porokeratosis (PK) is the cornoid lamella. The occurrence of the cornoid lamella within the follicular infundibulum and the acrosyringium is believed to be primarily associated with specific types of PK, for example, follicular PK, porokeratotic eccrine and hair follicle nevus. We looked for such occurrence in all cases of PK. Objective: We attempted to evaluate the incidence of follicular and acrosyringeal involvement in the various clinical types of PK in our population and describe the histological features of the same. Materials and Methods: Case records in 2011 were reviewed for patients diagnosed with PK based on clinicopathological correlation. The histology was reevaluated and follicular or acrosyringeal involvement was noted. Results: In total, biopsies from 28 lesions from 16 patients were reviewed. Nine (32%) lesions were found to have follicular involvement and 12 (42%) were found to have acrosyringeal involvement on histopathology. Of these, 61% of these patients were clinically diagnosed as PK of Mibelli (PM), 14% as disseminated superficial actinic PK (DSAP), 13% as linear PK (LP), 7% cases of follicular PK (FP), and 7% as genital PK. Conclusions: Follicular and acrosyringeal involvement in PK is more frequent than expected. Though follicular PK has been described as a distinct entity, there is no correlation between the clinical subtype and the involvement of the follicular infundibulum and acrosyringium. This involvement may occur as an incidental finding and hence, histological delineation of follicular or acrosyringeal PK as distinct entities without appropriate clinical correlation appears unjustified.