6. Myeloid sarcoma of the testis without involvement of bone-marrow based disease

Abstract

Myeloid sarcoma is a neoplasm of immature myeloid cells occuring in an extramedullary site. It rarely occurs in the testis and if so, is almost always associated with recurrent, co-existing or is the initial presentation of bone-marrow based disease. This is usually acute myeloid leukaemia and less commonly, myelodysplastic or myeloproliferative disorders. We describe a case of myeloid sarcoma as an isolated mass in the testis of a seventy-six year old; without past or current history of acute myeloid leukaemia. We discuss the histologic, cytochemical and immunohistochemical findings that brought us to the diagnosis. The differential diagnoses considered in this case include plasmacytoma, diffuse large B-cell lymphoma, anaplastic large cell lymphoma, precursor lymphoblastic lymphoma/leukaemia and metastatic amelanocytic melanoma. The literature was reviewed in order to calculate the range as well as mean interval time between first presentation of myeloid sarcoma and acute myeloid leukaemia and to calculate how long cases defined as myeloid sarcoma isolated to testis had been followed-up. Our aim is to determine how long such a patient should be followed-up for in order to accurately diagnose the entity of myeloid sarcoma confined to testis without bone-based disease.