[Truss-induced macular amyloidosis].
A 80-year-old male presented with a long time history of a localized red-brown macule with superficial lichenification and slight scaling in the right groin. An earlier skin biopsy revealed the presence of amyloid deposits. The patient therefore had a complete internal checkup including a rectal biopsy for exclusion of systemic amyloidosis. However, the laboratory data did not reveal any specific abnormalities including immunoglobulins and Bence-Jones protein. The rectal biopsy was also nonspecific. After skin examination, a rebiopsy was performed at our department showing acanthosis and spongiosis of the epidermis with parakeratosis. A homogenous eosinophilic deposit was present in the upper dermis and stained positive with thioflavine. At the second visit the patient wore a truss for a right inguinal hernia, perfectly matching the area of the skin lesion. Thus, the diagnosis of a localized macular amyloidosis was confirmed very likely due to permanent local friction. The classification of localized cutaneous amyloidoses should include local trauma as a cause to avoid unnecessary and exhausting internal checkups to exclude systemic involvement.