Bowen's and non-Bowen's squamous intraepidermal neoplasia of the skin. Relationship to internal malignancy.

The relationship of Bowen's disease to internal malignancy is controversial. We have studied 72 cases of Bowen's disease and compared them with 58 cases of non-Bowen's squamous intraepidermal neoplasia (SIN). Clinical data were obtained in all cases in an attempt to identify carcinogens and to detect the occurrence of other cutaneous or internal malignancies. Internal malignancy was not found more commonly in patients with Bowen's disease than in those with other forms of SIN. However, 5.7% of all patients win SIN were found to have a concurrent internal malignancy. Other cutaneous malignancies were also more frequent in these groups and may relate to sun exposure. Evidence for arsenic ingestion was not found in most patients. We believe that SIN either as Bowen's or non-Bowen's type may serve as an important marker for the presence of internal malignancy.