X-linked Emery-Dreifuss muscular dystrophy and vacuoles: an immunohistochemical characterization.

We report a striking abundance of rimmed vacuoles in two brothers with X-linked Emery-Dreifuss muscular dystrophy (X-EDMD) confirmed by the absence of emerin at the muscular nuclear envelope and by genetic analysis showing a new 2-bp deletion in exon 6 of the STA gene at the Xq28 region. Immunohistochemical analysis of the vacuoles revealed expression of dystrophin but not of merosin in the sarcolemma of rimmed vacuoles and absence of amyloid and membrane attack complex (MAC) deposition either in vacuoles or muscle fibers. The presence of rimmed vacuoles can be a histopathological finding in X-EDMD, and the diagnosis should not be excluded in clinically well-defined EDMD patients because of this finding.