THYMOMA: Histological Variants (Bernatz Scheme)

							INVASIVE THYMOMA
             THYMOMA:
Histological Variants (Bernatz Scheme)


      Lymphocyte-predominant (>66%
                lymphocytes)
   Mixed lymphoepithelial (>33 and < 66%
                lymphocytes)
      Epithelial-predominant (<33%
                lymphocytes)
        Spindle-cell (subtype of epithelial-
                predominant)
DIFFERENTIAL DIAGNOSIS OF THYMOMA
 BASED ON THE BERNATZ (“AMERICAN”)
       CLASSIFICATION SYSTEM

    Lymphocyte-predominant: Small lymphocytic,
   small cleaved-cell, and lymphoblastic lymphomas;
     small cell neuroendocrine carcinoma; PNET;
             embryonal rhabdomyosarcoma
  Mixed lymphoepithelial: Mixed non-Hodgkin’s and
           Hodgkin’s lymphomas; seminoma
  Epithelial-predominant: Large cell NHL; syncitial
       NS Hodgkin’s disease; germ cell tumors;
      neuroendocrine tumors; follicular thyroid
                        neoplasms
       Spindle-cell: Fibrohistiocytic tumors;
            hemangiopericytoma; spindle-cell
                 hemangioendothelioma
   STAGING OF THYMOMA:
Still the Best Prognostic Procedure

   Scheme of Masaoka et al. (Cancer 1981) is most
     widely used and shows good predictive value:
Stage I: Tumor confined by its capsule
Stage II: Tumor invades through capsule and
  involves adjacent tissue microscopically
Stage III: Macroscopic or microscopic involvement of
  lung, great vessels, or pericardium, by direct
  extension
Stage IV: Extensive seeding of pleura or
  pericardium, or extrathoracic metastasis (<10% of
  cases overall)
THERAPY AND PROGNOSIS OF
       THYMOMA

   Complete surgical removal, if at all
                   possible
 Uniform posteroperative irradiation for
    Masaoka stage II tumors and higher
   Chemotherapy for stage IV lesions
 Survival of stage I & II tumors is >90%
 at 5 yrs; approximately 50% for stage III
        lesions and 15% for stage IV