Examination of cutaneous macroglobulinosis by immunoelectron microscopy

Abstract

Cutaneous macroglobulinosis is a rare cutaneous manifestation of Waldenström's disease. Lesions are though to result from accumulation of macroglobulin in the dermis and are therefore called IgM storage papules. Ultrastructural findings in the previously reported cases were contradictory and the nature of the deposits was not established by electron microscopy. The purpose of this study was to analyse such deposits by the use of immunoelectron microscopy. A 60-year-old woman had multiple erythematous papules for 1 year. The histopathological changes consisted of plasmocytic infiltration of the dermis and eosinophilic deposits. The skin changes and other investigations led to a diagnosis of Waldenström's disease. Samples from normal and diseased skin were analysed by electron microscopy and by immunogold labelling with anti-IgM antibodies, after Lowicryl K4M embedding. An extracellular electron dense granular and filamentous material was observed in the mid- and upper dermis, between and within the collagen bundles. No periodicity was noted and no deposits were seen at the dermoepidermal junction. Immunoelectron microscopy showed a positive labelling located only on these deposits, in both normal-appearing skin and in lesions. In this patient, immunoelectron microscopy clearly demonstrated the presence of large amounts of IgM in the dermis, which were found in the lesions of cutaneous macroglobulinosis and in normal skin. These results suggest that the IgM storage papules result from a greater density of deposits rather than a site-specific accumulation.

Schnitzler syndrome: heterogeneous immunopathologicalfindings involving IgM-skin interactions

“…Skin biopsies were embedded at − 30 °C in Lowicryl K4M as described elsewhere. 13 Lowicryl ultrathin sections were collected on Formwar carbon‐coated nickel grids and floated on phosphate‐buffered saline (PBS) containing 1% normal goat serum (NGS). Grids were then floated overnight on PBS containing rabbit antihuman IgM antibodies (Dako).…”

Waldenström Macroglobulinemia–Induced Bullous Dermatosis

“…The presence of antibody along the dermoepidermal junction, as demonstrated by immunofluorescence and immunogold electron microscopy in this patient's skin, supports this. To our knowledge, this is the first case of a bullous eruption in Waldenströ m macroglobulinemia studied with electron microscopy and the immunogold technique, although Lipsker et al 19 used this method to study storage papules of this condition. …”

Firm Papules on Lower Extremities of 52-Year-Old Male

“…5 The deposits are PAS positive, diastase resistant, but do not stain with Congo red. 2,4,6 In one case, deposits appeared to contain fibrils, but this appears to be an exception. In the appropriate clinical setting, definitive diagnosis can be achieved with immunohistochemistry and immunofluorescence with anti-IgM antibodies and electron microscopy.…”