Abstract
Thymoma-associated multi-organ autoimmunity has rarely been reported to produce cutaneous lesions that mimic those seen in acute graft-versus host disease. We report a case of a sixty-five-year-old female with a history of myasthenia gravis and associated untreated malignant thymoma who presented from an outside hospital with a generalized erythrodermic and desquamative rash as well as pseudomonal bacteremia. The rash was predominantly on her trunk and extremities, consisting of erythroderma with scale and crusted areas of macerated erythematous papules, along with severe mucositis. Punch biopsies from her left knee demonstrated a lichenoid interface dermatitis with marked pigment incontinence and apoptotic keratinocytes in all levels of the epidermis. Direct immunofluorescence and serology studies (anti-smith, anti-Ro, anti-La) as well as paraneoplastic pemphigus panel were negative. She had no documented history of blood transfusions or prior stem cell or solid organ transplant. Given these findings, the diagnosis of graft-versus-host-disease-like erythroderma, a manifestation of the rare paraneoplastic disorder Thymoma-associated multi-organ autoimmunity, was favored. Although these patients have a poor prognosis due to increased risk of infection-related morbidity, the patient had near-complete resolution of her rash and was discharged within 2.5 weeks of admission following a course of oral steroids.