“Nonsecretory” Plasma Cell Myeloma: Observations on Seven Cases with Electron Microscopic Studies

Abstract

Azar, Henry A., Zaino, Edward C., Pham, Tuan Due, and Yannopoulos, Kaity: “Nonsecretory” plasma cell myeloma: Observations on seven cases with electron micoscopic studies. Am. J. Clin. Pathol. 58: 618–629, 1972. Seven cases of “nonsecretory,” but otherwise typical, plasma cell myeloma are reported. All were characterized by extensive osteolytic lesions and septic complications. In every instance, there was a moderate hypogammaglobulinemia with no detectable serum M-component or Bence Jones proteinuria. One patient had generalized amyloidosis. The “nonsecretory” myeloma cells were indistinguishable morphologically, including study by electron microscopy, from myeloma cells associated with monoclonal gammapathy. There was an abundance of rough, endoplasmic reticulum of the lamellar type or with variable degrees of cisternal dilatation. Because of the lack of differentiating features, and because of the finding of amyloid in one case, it was postulated that “nonsecretory” myeloma may produce protein fragments in amounts which are not identifiable as immunoglobulins or Bence Jones polypeptides by our present methods.