[Reticular erythematous mucinosis in a young woman with type 1 diabetes mellitus].

We report on an 18-year-old woman who presented to our clinic with chronic, persistent, brownish reticular skin changes. Her medical history revealed slightly elevated, erythematous, mildly scaly plaques that developed dark discoloration over time and became flatter. On full-body examination, confluent, extensive, ill-defined, brownish macules with a reticular pattern were observed bilaterally in the lumbosacral region and on the abdomen. Clinically, reticular erythematous mucinosis (REM syndrome) was suspected in the context of her known type 1 diabetes mellitus. Differential diagnoses included, among others, urticarial vasculitis, confluent and reticulated papillomatosis, and a late stage of prurigo pigmentosa, as these conditions may also present with reticular and/or hyperpigmented skin changes. Laboratory investigations revealed no evidence of vasculitis. Dermatohistopathological examination demonstrated predominantly subepithelial mucin deposition on alcian blue staining, confirming the suspected diagnosis of REM syndrome. Using this unusual case of an 18-year-old woman, we discuss the differential diagnoses and potential treatment options for REM syndrome.