Introduction. Micronodular thymoma with lymphoid stroma (MNTLS) is a rare thymoma subtype characterized by distinctive histological appearance, unique clinical profile, and indolent course with good prognosis. In addition to its distinctive morphology, MNTLS may be associated with diverse histological features, such as thymic cysts and conventional thymoma, complicating the diagnostic picture further. Materials and methods. We report herein an account of 3 elderly patients (male-02; female-01), who presented with anterior mediastinal mass, and underwent robotic thymectomy. Microscopic examination revealed MNTLS in all 3 cases. In addition, 2 cases showed associated histological features in the form of a multilocular thymic cyst and conventional (type B2) thymoma, respectively. All 3 patients are doing well without recurrence or metastasis at 34, 28, and 19 months postsurgery. Conclusions. Awareness of this rare thymoma subtype is vital among pathologists to avoid misdiagnosis and ensure appropriate patient management. To date, only a few cases of this rare thymoma subtype have been reported in the literature, mostly as single case reports.
Keywords: diagnosis; histomorphology; prognosis; thymoma; treatment.