Three-dimensional structure of a parameatal urethral cyst by scanning electron microscopy.

We report scanning electron microscopy (SEM) for a case of parameatal urethral cyst. A 6-year-old Japanese boy presented with a cyst on the right lateral side of the urethral meatus. Histological examination revealed a cyst lined with columnar epithelium. An immunohistochemical study showed positive staining for CK7, CK13, and CEA, and negative for CK20 in luminal cells. On SEM examination, the inner surface of the cyst showed ridges arranged in a gyrus-like manner at lower magnification. Higher magnification revealed luminal cells with short microvillus projections. Some cells showed apocrine, merocrine, and possibly holocrine-type secretions.