Paraneoplastic erythema annulare centrifugum eruption as a cutaneous marker of squamous cell carcinoma of the lung.

Erythema annulare centrifugum (EAC) is a chronic reactive form of annular erythema characterized by annular, arciform, and polycyclic erythematous plaques. The lesion usually lasts for a few weeks to a few months, migrating centrifugally with central clearing. EAC was first described by Darier in 1916 and classified in 1978 by Ackerman into superficial and deep type. The superficial form has minimally elevated "trailing scale" while the deep form is presented by non-scaly and non-pruritic lesions with indurated borders.