Prominent Plasmacytic Differentiation in the Recurrence of a Parotid Immunocytoma. A Morphologic and Immunohistochemical Study

Abstract

We report and discuss a case consisting of 2 lesions that developed at different times in the same parotid gland. Although the first lesion showed morphologic features similar to those of the benign lymphoepithelial lesion, a monotypic IgM/K pattern was also revealed by the immunoperoxidase method in its lymphoid infiltrates. Thus, on cytologic grounds, the first lesion was classified as lymphoplasmacytic immunocytoma (according to Kiel criteria). In the second lesion, which recurred 3 years later, the prominent feature was a marked predominance of plasma cells with the same monoclonal IgM/K as the preceding lymphoma. These findings suggests that a B-lymphomatous cell monoclone may undergo morphologic maturation along the lineage of its competence. Secondly, they indicate that every case of benign lymphoepithelial lesion of the salivary glands should undergo thorough immunologic evaluation to exclude the possibility of signs of precocious lymphomatous transformation.

Extramedullary plasmacytoma of the parotid gland: Report of a case and review of the literature.

“…The previous reports (Vainio-Mattila 1965;Koop and Carley 1966;Pascoe and Dorfman 1969;Gromer and Duvall 1973;Wiltshaw 1976;Pahor 1977;Ferlito et al 1980;Palestro et al 1983) and our new case are summarized in Table 1. In the absence of monoclonal immunoglobulins in the serum and/or urine, immunohistochemical studies to confirm a monoclonal proliferation are essential for the diagnosis of PEMP (Regezi et al 1983).…”

“…Received December 24, 1984; accepted for publication May 1, 1985May 1, . 469 1969Gromer and Duvall 1973;Wiltshaw 1976;Pahor 1977;Ferlito et al 1980;Palestro et al 1983) has revealed only 9 cases of PEMP in the salivary glands, including our new case and inadequate ones. The purpose of this report is to describe a new case of PEMP involving the parotid gland which was examined by immunologic methods, and to summarize these 9 cases in order to discuss problems connected with the clinical, pathological and therapeutic aspects of PEMP with special regard to the rare parotid location.…”

Monoclonal gammopathy after low‐grade MALT lymphoma: Evidence for a second neoplasm

“…Palestro et al reported a case of a lymphoplasmocytic immunocytoma of the parotid gland that 3 years later showed a marked predominance of plasma cells with the same monoclonal IgM/j as the preceding lymphoma. The authors suggested that a B-lymphocytic clone may undergo morphologic maturation along the lineage of its competence [18]. In follicular lymphomas, Frizzera et al described several cases with an abundant plasma cell component [19].…”

Primary extramedullary plasmacytoma of the salivary glands

“…Salivary gland PEMP's are challenging to the pathologist because they have variable histological features, can be poorly differentiated, and can have clinical and histological features similar to other lesions. Frozen and permanent sections of these tumours have been mistaken for sarcoid (Pahor, 1977), undifferentiated carcinoma (Pascoe and Dorfman, 1969) and inflammatory lesions (Koop and Carley, 1976;Palestro et al, 1983) resulting in incorrect initial histological diagnoses in 36 per cent (5/14) of cases.…”

“…Histological differential diagnosis of these lesions would include other malignant processes such as lymphoma, undifferentiated carcinoma, and melanoma (Kapadia etal., 1982;Palestro et al, 1983); and benign processes such as plasma cell granuloma and pseudolymphoma. Electron microscopy and immunohistochemical stains that detect the monoclonal antibodies produced by these tumours are invaluable for differentiating plasmacytomas from these other conditions (Kapadia etal., 1982).…”