Suspected Pulmonary Metastasis of Actinic Cutaneous Squamous Cell Carcinoma.

Introduction. It is rare for actinic or squamous cell carcinoma (SCC) in situ to metastasize. Case Presentation. A 67-year-old male had a significant medical history including severe psoriatic arthritis treated with UVB, methotrexate, and rapamycin. He had twenty-five different skin excisions of actinic keratosis four of which were invasive SCC. Our patient developed shortness of breath necessitating a visit to the emergency department. A CT scan of his chest revealed a mass in the right lower lung. A subsequent biopsy of the mass revealed well-differentiated SCC. He underwent thoracoscopic surgery with wedge resection of the lung lesion. Discussion. Actinic keratosis (AK) is considered precancerous and associated with UV exposure. It exists as a continuum of progression with low potential for malignancy. The majority of invasive SCCs are associated with malignant progression of AK, but only 5-10% of AKs will progress to malignant potential. Conclusion. In this case, a new finding of lung SCC in the setting of multiple invasive actinic cutaneous SCC associated with a history of extensive UV light exposure and immunosuppression supports a metastatic explanation for lung cancer.