Timoma quístico micronodular con hiperplasia linfoide B. Presentación de un caso Micronodular thymoma with lymphoid B-cell hyperplasia. Report of a case

SUMMARY Introduction: Micronodular thymoma with lymphoid B-cell hyperplasia is a new type of epithelial thymic neo- plasms, included in the last WHO classification. Clinical findings: The case we explain below is about a 67 years old woman presenting with a big and asynthomatic cyst in the left intrathoracic cavity, which was diagnosed by an x-ray exploration. The physical examination was absolutely nor- mal. Results: Microscopically, we observed multiples epi- thelial nodules separated by an abundant lymphocytic stro- ma with follicular germinal centres.