[Borrelia-associated lymphocytoma cutis]. / Le lymphocytome borrélien du lobe de l'oreille.

We describe a 6-year-old boy who developed Borrelia burgdorferi-associated lymphocytoma cutis on the ear. Lymphocytoma is a benign polyclonal B-cell lymphoproliferative process; it is defined as a subacute manifestation of early disseminated borrelial infection. Clinical history, physical examination, and serodiagnosis tests are often sufficient to establish diagnosis, but sometimes, histopathologic analysis is needed to exclude malignant cutaneous lymphomas. The outcome is always favorable but after antibiotic therapy, the lesion disappears promptly.

MUC1 (EMA) expressing plasma cells in bone marrow infiltrated by plasma cell myeloma.

MUC1 (also called: epithelial membrane antigen, EMA) represents a mucin molecule strongly expressed in various epithelia and epithelial neoplasms. Its expression correlates with clinical and pathological factors as well as prognosis in some tumor types. Additionally, MUC1 was detected in normal haematopoietic cell lines and neoplasms, especially subgroups of human lymphomas including plasma cell myeloma. Therefore, the expression of MUC1 in trephine biopsies exhibiting infiltrates of plasma cell myeloma were investigated immunohistochemically. An immunoreactivity of two monoclonal antibodies (EMA and HMFG-2) was observed in about 50% of the cases. In cases exhibiting a so-called packed marrow, EMA immunoreactivity was reduced. However, MUC1 positivity did not correlate with the cytologic grade of differentiation, the fibre content of the marrow, or survival probability of the patients. However, its strong expression in a certain percentage of cases of plasma cell myeloma may be of therapeutic impact, since new therapeutic strategies include the enrichment of MUC1-specific T cells or MUC1 vaccination.