Mucicarminophilic histiocytosis. A polyvinylpyrrolidone (PVP) storage disease simulating signet-ring cell carcinoma

In Taiwan, a peculiar type of cell with mucicarmine-positive bubbly or vacuolated cytoplasm was sporadically observed in a variety of surgical specimens removed for neoplastic or non-neoplastic conditions. They closely mimicked signet-ring cell carcinoma. Study of 14 such cases and review of the related literature led to the conclusion that the peculiar cells were storage histiocytes containing polyvinylpyrrolidone (PVP). Because they were shown to be mucicarmine-positive, we designated them 'mucicarminophilic histiocytes'. Particulate bodies sometimes observed in association with mucicarminophilic histiocytes were believed to be the extracellular counterpart of the cytoplasmic vacuoles. Our survey also revealed that PVP-containing intravenous injection fluids had been used in Taiwan as recently as 5 years ago. For surgical pathologists, PVP-containing mucicarminophilic histiocytes should not be mistaken for signet-ring cell carcinoma or signet-ring cell lymphoma. Mucicarminophilic histiocytes can be identified by the positive mucicarmine, colloidal iron, Gomori methenamine silver, Congo red, Suden black B, Fontana-Masson argentaffin, and Victoria blue; but negative periodic acid-Schiff, alcian blue, and Giemsa stains.