Graft-versus-host disease-like erythroderma in the setting of thymoma: A rare paraneoplastic disorder

Summary: Herein we present a case of a 45-year-old female with diffuse erythroderma preceding resection of a thymoma. The patient’s course was complicated by post-operative multi-organism septicemia, including erythroderma (90% of the body surface) with crusted erythematous plaques and scaling. Histopathologic examination demonstrated epidermal verrucous acanthosis with interface vacuolar change, necrotic keratinocytes, superficial dermal lymphocytes with exocytosis, and pigment incontinence with few eosinophils (consistent with an interface dermatitis). The clinical and histologic findings aligned with the paraneoplastic entity, “Graft-versus-host disease-like (GVHD-like) erythroderma in the setting of thymoma.” GVHD-like erythroderma is an uncommon manifestation of thymoma-associated multiorgan autoimmunity (TAMA), a subtype of thymoma-associated paraneoplastic disorders (i.e. myasthenia gravis, pure red cell aplasia, etc.). Less than twenty cases of GVHD-like erythroderma have been documented in the literature, with rare cases reporting coinciding TAMA manifestations (i.e. GVHD-like colitis). Histologic manifestations may consist of an interface dermatitis; however, there remains no established diagnostic criteria and recognition is often dependent on clinicopathologic correlation. Standard treatment has yet to be established; however, the typical therapeutic regimen includes immunosuppression and narrow-band UVB phototherapy. Despite treatment, prognosis is poor with reports of mortality within 1 year of diagnosis. Our aim is to increase diagnostic awareness of this rare entity.