| [ Summary ] |
Perianal Pagetʼs disease is rare. There are two types of Pagetʼs disease. Primary cutaneous malignancy is designated as the primary symptom of extramammary Pagetʼs disease (EPD). A secondary disease associated with adjacent visceral invasive carcinoma is secondary EPD, known as the Pagetoid phenomenon. Despite similarities in clinical appearance, there is a significant difference in the prognoses for these conditions. It is difficult to distinguish between primary and secondary EPD based on clinical or routine/histological findings. Therefore, immunohistochemical analysis of CK7/CK20/GCDFP-15 expression is very useful in differentiating primary from secondary EPD. Secondary EPD exhibits the immunophenotype CK7+or-/CK20+/GCDFP-15-, primary EPD exhibits the CK7+/CK20-/GCDFP-15+.
A 76-year-old man presented with a primary complaint of pruritus and skin rash in the perianal region. Colonoscopic examination revealed no masses in the anal canal. Histological examination of skin biopsies taken from the perianal erosion revealed the presence of Pagetʼs cells. To determine the origin of these Pagetʼs cells, immunohistochemical analysis of CK7/CK20 expression was performed. These immunohistochemical studies reveled that the rectal adenocarcinoma was composed of CK20 but not for CK7. We diagnosed the lesion as being a Pagetoid phenomenon, associated with anal canal carcinoma. |