Cutaneous ciliated cyst: a case report with immunohistochemical evidence for dynein in ciliated cells.

Cutaneous ciliated cysts (CCCs) are rare benign lesions predominantly occurring in the lower limbs of young women. We observed such a lesion in the perineal region of a 12-year-old girl. The histogenetic interpretation of CCCs is controversial. The similarity of the epithelial lining of the cyst to the salpingeal epithelium supports the hypothesis of a Müllerian heterotopia. Strong dynein positivity observed immunohistochemically in the apical portion of CCC lining cells suggests the integrity of the ciliary apparatus. There was a marked similarity between a CCC and normal salpingeal epithelium in the mode of staining for dynein, whereas the dynein reactivity of bronchial epithelial cells showed larger cytoplasmic aggregates of positive material in proximity to the nucleus. No immunohistochemical staining for estrogen or progesterone receptors was identified in our observation, although this finding could have supported the Müllerian histogenetic hypothesis. To the best of our knowledge, this is the first time that antidynein immunohistochemistry has been applied to paraffin-embedded samples from human surgical pathology.