Klinefelter's syndrome with lupus encephalitis and retroperitoneal teratoma

We report a case of a middle-aged male who presented with pyrexia of unknown origin, oral ulcers, rash and bicytopenia. His past medical history included unexplained proteinuria, infertility and joint pain. Initial workup showed a large retroperitoneal soft tissue mass, which has appeared stable for 10 years. He subsequently developed neuropsychiatric symptoms with imaging findings of meningoencephalitis. Concurrent investigations showed elevated ANA, anti-double-stranded DNA (dsDNA) and ESR levels, as well as low complement levels. Bone marrow aspirate samples revealed karyotype of chromosome 47, XXY. The unifying diagnosis was therefore Klinefelter's syndrome (KS) with retroperitoneal teratoma and systemic lupus erythematosus (SLE), with manifestations of cytopenias, myositis, serositis, cutaneous vasculitis, encephalitis and nephritis. Upon commencing immunosuppressive therapy, there was dramatic improvement in his mental state and resolution of imaging findings. This case illustrates that males with KS may develop severe SLE manifestations; hence, increased diagnostic vigilance of KS in males with SLE is important in order to recognize effects of hypogonadism and other associations with KS such as retroperitoneal teratoma.