Apocrine acrosyringeal keratosis in association with syringocystoadenoma papilliferum

We report the clinical and histopathological features of a keratosis that d eveloped in association with syringocystadenoma papilliferum. This tumour s hows a pinkish, pedunculated, spherical nodule with a cerebriform surface a nd visible keratinous plugs. In addition to the typical features of syringo cystadenoma papilliferum, the tumour shows many hyperkeratotic columns surr ounded by acanthotic epidermis with the characteristics of trichilemmal ker atinization and keratohyalin granules. This keratosis seems to be derived f rom the middle to lower portion of the apocrine acrosyringium, based on the distribution of keratohyalin granules and the direct connection with the a pocrine acrosyringium in an early lesion. Accordingly, we propose to identi fy this rare keratosis as apocrine acrosyringeal keratosis.