The authors have indicated no significant interest with commercial supporters. W e report an arc welder who developed 51 squamous cell carcinomas (SCCs) on the dorsal upper extremities after 10 years of unprotected arc welding. SCCs began to appear 27 years after he started welding. Mohs surgery and acitretin were necessary to control his disease.
Case ReportA 52-year-old Caucasian man, Fitzpatrick skin type III, was referred to our clinic in 2007 for three eruptive SCCs adjacent to two recent surgical sites in which tumor-free margins were confirmed. Past history was negative for carcinogenic exposure and immunosuppression. As a child and teenager, he participated in outdoor activities on the weekends and summers and had occasional sunburns. Other sources of significant sun exposure were not identified. He had received multiple tattoos on his upper extremities beginning approximately 30 years before his initial visit. Occupational history revealed that he had worked as a metal arc welder indoors in a boiler plant beginning 27 years before the eruption of his first SCC. He welded approximately 4 hours per day for 10 years and reported not wearing protective clothing. Typical work attire included a sleeveless shirt, jeans, and leather boots. He reported multiple small burns from molten metal spatter and feeling "sunburned" on his upper extremities after welding. Initial examination revealed multiple small circular scars and ultraviolet radiation (UVR) damage, which consisted of spotty depigmentation, hyperpigmentation, and mild erythema of the exposed face, neck, and upper extremities. A small number of fine actinic keratoses were noted on the upper extremities. Multiple multicolored and black tattoos were noted on his dorsal upper extremities. Mohs surgery was used to treat the three SCCs and two additional SCCs found on initial examination (Figure 1), with suspected metal fragments found intraoperatively. Acitretin was started at his initial visit in 2007. He continued to develop multiple keratoacanthomas (KAs) adjacent to surgical sites and SCCs at distant sites, with a halt of tumor formation in 2009. Acitretin was discontinued in 2010 after a 1-year tumor-free period. In 2012, tattoo application over preexisting tattoos (Figure 2) resulted in the formation of new eruptive SCCs and KAs within these tattoos (Figure 3). Of 54 total lifetime skin cancers, all were SCCs-51 on the dorsal upper extremities and three on the face. The location and associated factors for the 51 SCCs are depicted in Figure 4. All sites were treated using Mohs surgery. Examination for occult malignancy was negative.