Pagetoid bowen disease: a report of 2 cases that express cytokeratin 7.

Bowen disease is a variant of squamous cell carcinoma in situ. In some cases a pagetoid growth pattern can be observed with cytologically atypical clear cells arranged singly and in nests. The differential diagnosis of pagetoid Bowen disease includes primarily Paget disease and malignant melanoma in situ, as well as other less common entities. Two cases of pagetoid Bowen disease are described, one in a 65-year-old man with a thigh lesion and the other in a 25-year-old man with a lesion in the penile/scrotal region. Neither patient had clinical evidence of an internal malignant neoplasm. In both cases, the neoplastic cells were positive for cytokeratin (CK) 7 and CK 19 and were negative for CK 18, CK 20, carcinoembryonic antigen, GCDFP-15, c-erbB2, S100, and HMB-45. In aggregate, these findings support the diagnosis of pagetoid Bowen disease. Previously, others have shown that CK 7 is an almost invariable marker of Paget disease. Thus, we report these two cases to illustrate that CK 7 can be expressed by pagetoid Bowen disease and should not be a cause of confusion in the differential diagnosis.