Ectopic primary type A thymoma located in two thoracic vertebras: a case report.

Background: The thymus arises in the ventral portion of the third and fourth pharyngeal pouch. It descends into the anterior mediastinum at 6th week of gestation. Any errors occurring during this process can cause dissemination of aberrant nodules that are responsible for most atypical thymomas.

Case Presentation: The authors report a unusual case of type-A thymoma located in D10 and D11 vertebral bodies.The histology showed a uniform growth of short, spindle shaped, mitotically inactive cells. A few small, normal lymphocytes were seen scattered or in small groups. The immunohistochemical investigation for neuroectodermal, neuroendocrine, vascular and muscular markers were negative. It also confirmed the presence of CD3+, CD5+ T lymphocytes and the absence of immature T-lymphocyte markers.

Conclusions: The case described shows a thymic hystogenesis for spindle cell tumours. To our knowledge no other cases of vertebral thymomas have been described in international literature.