SALIVARY-GLAND LYMPHOID INFILTRATES ASSOCIATED WITH LYMPHOEPITHELIAL LESIONS - A CLINICOPATHOLOGICAL, IMMUNOPHENOTYPIC, AND GENOTYPIC STUDY

The criteria for distinguishing benign lymphoepithelial lesions (BLEL) from low grade B-cell lymphomas of mucosa-associated lymphoid tissue (MALT) type in salivary glands and the significance of genotypically d ocumented clonality in this setting are controversial. In addition, th e clinical implications of a neoplastic diagnosis are unclear. The his topathologic features of 68 specimens from 49 patients with at least o ne salivary gland biopsy with LEL together with available clinical dat a were, therefore, reviewed. Paraffin section immunohistochemical (MC) stains for kappa, lambda, CD3, CD20, and CD43; in situ hybridization (ISH) for kappa and lambda; and polymerase chain reaction (PCR) for im munoglobulin (Ig) HC rearrangement were performed. The 61 salivary gla nd specimens were classified as BLEL-13, BLEL with monocytoid B-cell ( MBC) halos (BLEL-halo-8), low grade B-cell lymphoma of MALT type with confluent zones of MBC or other atypical lymphocytes (ML-MALT-24), lo tv grade B-cell lymphoma of MALT type with monoclonal plasma cells (ML -MALT-PC-12), and high grade B-cell lymphoma of MALT type (MALT-high g rade-4). Soft tissue and perineural invasion was not observed in BLEL and was most common in the MALT lymphomas. Lymph node involvement was identified in six patients at the time of their salivary gland MALT ly mphomas but in none with BLEL. CD43 + B cells were seen most commonly in hit-MALT but were present in all other categories except MALT-high grade. Clonal B cells were identified by PCR in 5 of 12 BLEL, 5 of 8 B LEL-halo, 17 of 22 ML-MALT, 6 of 10 ML-MALT-PC, and 3 of 3 MALT-high g rade biopsies. All ML-MALT-PC were clonal by ISH or IHC. Repeat biopsi es in 14 patients most commonly showed a BLEL/ML-MALT lesion in an ips ilateral or contralateral salivary gland with one transformation to a MALT-high grade. Although only a few patients are known to have receiv ed chemoradiation or radiation therapy, most patients with low-grade l esions have pursued an indolent course. These data show the presence o f two types of borderline lesions within the spectrum of lymphoid prol iferations associated with salivary gland LEL. One has clonal B cells without histological features of neoplasia and the other nonconfluent MBC extending beyond the confines of LEL (''halos''). They share some features with the infrequent nonneoplastic BLEL and others with the mo re common low-grade B-cell lymphomas of MALT. A few high-grade B-cell lymphomas of MALT were also identified including a rare example of tra nsformation from a low- to high-grade lesion. The optimal therapeutic approach for the borderline and low-grade lesions and the reason why s o many of the lymphoproliferative lesions associated with LEL remain l ocalized to the neck remain to be defined. HUM PATHOL 28:850-861. Copy right (C) 1997 by W.B. Saunders Company.