ALUMINUM AND INJECTION SITE REACTIONS

Aims-To alert pathologists to the spectrum of histological appearances that mag be seen in injection site reactions related to aluminium. Me thods-Four cases of injection site reaction were examined microscopica lly using routine staining with haematoxylin and eosin, electron micro scopy and by electron probe microanalysis. Results-As in previous repo rts, all four cases included collections of histiocytes which containe d faint granular brownish refractile material within their cytoplasm; ultrastructural examination showed this to be aluminium. Two cases sho wed a prominent inflammatory reaction with numerous lymphoid follicles and a notable eosinophilic infiltrate. Two cases showed unusual featu res not described previously. In one, there was a sclerosing lipogranu loma-like reaction with unlined cystic spaces containing crystalline m aterial. The other case presented as a large symptomatic subcutaneous swelling which microscopically showed diffuse and widespread involveme nt of the subcutis by a lymphoid infiltrate with prominent lymphoid fo llicles. Conclusions-This report highlights the changes encountered in aluminium injection site reactions and emphasises that the lesions ha ve a wider range of histological appearances than described previously .