Is pyoderma gangrenosum associated with solid malignancies? Insights from a population-based cohort study

Background: The question of whether solid malignancies (SMs) are associated with pyoderma gangrenosum (PG) remains to be conclusively answered. Objective: To evaluate the risk of SM among patients with PG and the odds of PG after a diagnosis of SM. Methods: A population-based retrospective cohort study was conducted to study the risk for SM in patients with PG (n = 302) as compared with age-, sex- and ethnicity-matched control subjects (n = 1799). A case-control design was used to estimate the odds of PG in those with a preexisting history of SM. Results: The prevalence of a preexisting SM was comparable in patients with PG and controls (7.5% vs. 8.8%, respectively; P = 0.490). The odds of having PG following a diagnosis of a SM was not statistically increased (OR, 0.85; 95% CI, 0.53-1.36). The incidence of SM was 6.8 (95% CI, 3.5-12.2) and 7.9 (95% CI, 6.1-10.1) per 1000 person-years among patients with PG and controls, respectively. Patients with PG were not more likely to develop SM as compared to controls (HR, 0.86; 95% CI, 0.44-1.69). Patients with a dual diagnosis of PG and SM were older and had more frequent comorbid conditions and increased mortality. Conclusions: SM is not associated with provoking PG, and patients with PG are not at an increased risk of developing SM. A thorough routine screening for SM in patients with new-onset PG is an unnecessary approach based on the study findings.