Nodular amyloidosis: differentiation from colloid milium by electron microscopy.

Nodular amyloidosis is a primary cutaneous amyloidosis characterized by the deposition of amyloid L-type fibril proteins in the dermis. Clinical history and routine histology may not be sufficient to differentiate nodular amyloidosis from colloid milium. We present a case of a 45-year-old man with nodular amyloidosis, whose diagnosis was confirmed by the characteristic appearance of filaments on electron microscopy.