Hypothyroidism Potentially Linked to Cutaneous Squamous Cell Carcinoma: Retrospective Study at a Single Tertiary Academic Medical Center.

BACKGROUND: There are multiple known risk factors for the development of cutaneous squamous cell carcinoma (SCC). OBJECTIVE: To determine whether patients with cutaneous SCC have a higher prevalence of hypothyroidism than the general US population. MATERIALS AND METHODS: A retrospective review was performed for patients seen at the University of Southern California with cutaneous SCC. Chart review was performed for the presence of hypothyroidism and thyroid replacement therapy before the diagnosis of SCC for each patient. Multiple prevalence studies were gathered from the literature for comparison, reporting the prevalence of overt and subclinical hypothyroidism in the general US population and/or elderly US population. RESULTS: Of the 265 patients diagnosed with SCC of the skin, 61 (23%) of patients were found to have a preceding diagnosis of hypothyroidism. The prevalence of hypothyroidism among the population of SCC patients was significantly greater than the prevalence of hypothyroidism (overt and subclinical) in any general and/or elderly US population reported. CONCLUSION: Patients with SCC of skin are more likely to have a history of hypothyroidism than the general population. The authors conclude that hypothyroidism may be linked to the development of cutaneous SCC.