[The prognosis and immunohistochemical evaluation of five perianal Paget's disease cases]

Perianal Paget's disease is categorized as Paget's disease, which is epidermotropic neoplasm arising from the apocrine glands of perianal region, or Pagetoid spread invaded from rectal or anal canal cancer. It has been reported that the immunohistochemical staining of GCDFP15, the marker of the apocrine epithelium, and CK20 is used to be distinguished between Paget's disease and Pagetoid spread. Five patients with perianal Paget's disease who underwent a surgical operation had been treated in our department between 1997 and 2006. We analyzed the clinical findings and the treatment of these patients and investigated the expression of GCDFP15 and CK20 by immunohistochemical staining. All cases presented the redness around perianal regions, and 2 cases were recognized a tumor at the anal canal. We preoperatively diagnosed these cases as Pagetoid spread and others without tumor regions as Paget's disease. Surgical treatment was performed for all patients. As a result of immunohistochemical staining, 2 cases of Pagetoid spread were negative for GCDFP15, and positive for CK20. It was compatible with the preoperative diagnosis. Only one of 3 Paget's disease cases was positive for GCDFP15 and negative for CK20 resulting in the diagnosis of perianal Paget's disease. Based on the expression of negative for GCDFP15 and positive for CK20, others were seemed to be Pagetoid spread. A treatment strategy including surgical operation and chemotherapy is different between patients with Paget's disease and those with Pagetoid spread. Therefore, it is essential to investigate the expression pattern of GCDFP15 and CK20 using the tissue from the biopsy to identify the disease for appropriate treatment.