Asteroid bodies in mature cystic teratomas

Sir: I read the article ‘Cutaneous ciliated cyst: a case report and immunohistochemical comparison with fallopian tube’l with great interest. The authors proposed that cutaneous ciliated cyst is a distinct entity, occurring in females during the reproductive period, and that its histological and immunohistochemical similarity to the fallopian tube suggests a derivation from heterotopic Miillerian epithelium. We have found S-100 protein antigen expression in the lining cells of fallopian tubes removed for ectopic pregnancy. However, no immunoreactivity with S-100 protein antibody was observed in fallopian tube segments removed for sterilization or hydrosalpinx. Nakamura et aL2 also reported S-100 protein immunoreactivity in the glands within decidua and in endocervical polyps during early gestation. These results suggest a possible relationship between pregnancy hormones and S-1 00 protein expression. Thus, immunostaining for S100 protein in a cutaneous ciliated cyst in a woman with complex gynaecological history may also be the result of such an association. However, the authors have not mentioned in how many fallopian tubes S-100 protein was expressed and what the indications were for tubectomy. S-100 protein expression in the cutaneous cyst, in view of the above observation, supports its histogenesis from heterotopic Miillerian epithelium.