Graft-versus-host disease-like erythroderma: a manifestation of thymoma-associated multiorgan autoimmunity.

Thymoma associated multiorgan autoimmunity is a rare paraneoplastic disorder, clinicopathologically similar to graft versus host disease, which is thought to be mediated by dysfunctional negative thymocyte selection and abnormally low levels of Tregs. We report a 50 year old Chinese women with a history of malignant thymoma and myasthenia gravis who developed graft versus host disease- like erythroderma after instituting chemotherapy and undergoing myasthenia crisis. Clinically her rash presented as erythematous scaly papules, which evolved to psoriasiform patches and plaques with foci of vitiligo. Histopathologically the biopsy showed a predominantly interface dermatitis with necrotic keratinocytes extending to the upper levels of the epidermis, and florid basket weave orthokeratosis. Clinical and laboratory work-up ruled out common inflammatory or infectious causes, eventually favoring the diagnosis of TAMA with GVHD-like erythroderma. Unfortunately, the patient underwent multi-organ compromise and death due to respiratory failure from myasthenia crisis. Patients with TAMA have a poor clinical outlook; rare successful treatments include high dose oral steroids and additional modalities including bone marrow transplant and chemotherapeutic or biologic agents. As the predominant findings are in the skin, dermatologists and dermatopathologists are in a unique position to enable the early diagnosis and treatment of this unusual disease.