Malakoplakia and malakoplakialike lesions of the upper gastrointestinal tract.

This report describes the clinical and pathologic features of 3 cases of unusual lesions that bear a striking similarity to malakoplakia. The lesions were located in the stomach, submental region, and oropharyngeal soft tissues. The cellular infiltrates were composed of sheets of mononuclear cells with abundant, granular, eosinophilic cytoplasm. Nuclei were small and bland, and mitoses were extremely rare. Lymphocytes and plasma cells were present in varying numbers. Ultrastructural studies revealed unusual crystalline structures within dilated cisternae of rough surfaced endoplasmic reticulum of plasmacytoid cells in all 3 cases. The 3 cases may represent a morphologic spectrum of chronic immunologic stimulation, with the crystalline structures limited to stimulated lymphocytes of gastrointestinal tract lesions.