Discussion & Conclusion
Psoriasis is a systemic immune-mediated and genetic disorder defined by overgrowth and differentiation of keratinocytes. Environmental stimuli trigger the process of disease in susceptible individu­als. This pathologic interaction occurs among skin cells, immunocytes and numerous biologic signaling molecules. Through activation of TH1, TH17, TH22 cells, these cells cause a chronic inflammatory state, alter proliferation of keratinocytes and release of several interleukins responsible for development of psoriasis.1 Increased risk of malignant cancer development in patients with psoriasis has been investigated recently. In several studies, the total cancer incidence rate was higher than general population. Subsequently SCC was the second most prevalent cancer among psoriatic patients.2, 3 However it is still unclear whether the correlation of SCC with psoriasis is due to underlying genetic basis of disease or its treatments. Phototherapy, immunosuppressive therapy and other well-known therapeutic methods have made it challenging to estimate the baseline risk of SCC incidence in psoriatic patients. So far several studies showed positive association of such therapies on development of SCC. And the effect of certain psoriasis treatments on incidence of SCC has been proven.4 A systematic literature review conducted by E. Archier et al. showed an increased risk of SCC following oral psoralen and ultraviolet A (PUVA), a considerable and advantageous therapeutic method.5 Systemic non-biologic therapies such as methotrexate and cyclosporine have also been associated with higher risk of malignancies. These two agents are associated with increased risk of SCC in psoriatic patients, elevated by PUVA therapy. Moreover tumor necrosis factor-a Inhibitors (anti-TNFa) were associated with considerably higher risk of SCC development in psoriatic patients, increased by primary PUVA exposure and/or immunosuppressive therapy.4 However since most studies include treated and untreated patients together, we have no available data on potential risk of SCC development in patients without any well-defined therapy. In this article we report a 45‑year‑old male patient with psoriasis who have been treated with topical agents and multiple tumoral lesions developed over his scalp eight years after his first initial diagnosis. This case states that the potential risk of SCC development in patient with psoriasis is probably not just due therapeutic side effects. Further investigations are needed to clarify underlying pathobiology of SCC development in these patients. Moreover periodic screening for prevalent cancers such as SCC is warranted in patients with psoriasis.