Abstract
Background : Myeloid sarcoma (MS) is defined as an extramedullary tumor consisting of myeloblasts. Here we report a non-leukemic patient with MS associated with left pleural and pericardial effusion occurring at the mediastinum and pelvic space.
Case : A 32-year old female with the complaints of a fever and chest pain was admitted at our hospital. Computed tomography scan revealed mediastinal, pelvic masses, left pleural and pericardial effusion. Malignant lymphoma (ML) was initially diagnosed with cytologic examination of the left pleural effusion. However, lymphocyte markers for lymphocytes were negative. When we reviewed the cytology specimens stained with Papanicolaou or Giemsa, we found the characteristic of atypical cells that had a large, round nucleus with fine granular chromatin and also azurophil granules in the cytoplasm, including 11% of all atypical cells that had a highly curved nucleus. The cell block specimen or tissue specimens obtained from the mediastinal tumor showed immunohistochemical positivity for myeloperoxidase. Therefore we finally diagnosed MS in this case.
Conclusion : Because the cell morphology of MS is similar to that of ML, it can be easily misdiagnosed as ML even in tissue specimens. The characteristics of cytology of MS presented in this case may be helpful for the early diagnosis.
