DP21 Thymoma and the skin: manifestations of multiorgan autoimmunity

Abstract We present three patients who developed distinct cutaneous manifestations of thymoma: a rare mediastinal tumour. A 25-year-old man was treated for myasthenic crisis. Past medical history included thymectomy in 2016. Admission imaging confirmed recurrence thymoma. He red–brown macular rash affecting the trunk, back and thighs. Biopsy showed florid lichenoid dermatitis consistent with graft-versus-host disease (GVHD). After resolution steroids mycophenolate mofetil, he subsequently Stevens–Johnson syndrome/toxic epidermal necrolysis-like eruption erythroderma loss. Unfortunately, multiorgan failure died shortly afterward. 43-year-old presented to emergency dermatology clinic 4-month blistering chest limbs. His previous significant thymoma 2008 2013. Skin biopsy demonstrated changes suggestive bullous pemphigoid, repeat computed tomography Enzyme-linked immunosorbent assay testing positive pemphigoid 180. has responded well prednisolone doxycycline. 51-year-old woman reviewed 2020 2021 pruritic hyperpigmented patches face, trunk Her past several relapses occurrence 2002 2007, 2008, 2011, 2015 2021. June features GVHD. She received ruxolitinib tapering thymoma-associated autoimmunity (TAMA)-like GVHD had remarkable improvement her skin disease. Thymoma is described as neoplasm, up 34% thymomas are thought be accompanied by symptoms autoimmunity. The most frequently syndromes include myasthenia gravis, pure red blood cell aplasia hypogammaglobulinaemia. Other reported presentations panencephalitis, enterocolitis autoimmune hepatitis. have been previously described, often association two syndromes: TAMA paraneoplastic syndrome (PAMS). Both conditions demonstrate variability clinical phenotype, driven activation humoral cellular immune responses. Clinically, may spectrum disease, including GVHD-like exanthems, lichen planus-like pemphigus-like pemphigoid-like lesions. Our case series demonstrates heterogeneous thymoma-induced also describe extremely phenomena accompanying thymomas: PAMS. suggest that there much crossover between these definitions require further review. This highlights importance wider multidisciplinary team managing complexities their