Testicular myeloid sarcoma: a relapse of acute myeloid leukaemia after allogeneic peripheral blood stem cell transplantation- a rare presentation.

Myeloid sarcoma is an uncommon pathological diagnosis of proliferation of blasts of one or more of the myeloid lineages in regions other than the blood and bone marrow. Myeloid sarcoma of the testis after allogeneic bone marrow stem cell transplantation is very rare and only few cases are reported in the literature. It is usually misdiagnosed as malignant lymphoma, particularly with large cell lymphoma, due to similar histological morphology. Due to difficulty in diagnosis, it is suggested that an appropriate panel of immunohistochemical marker studies be performed in conjunction with clinical correlation to avoid misleading diagnosis and improper treatment of patients. We report an interesting case of a 49-year-old man with a diagnosis of acute myelogenous leukaemia. He had undergone allogeneic peripheral blood stem cell transplantation, achieved complete molecular remission and later relapsed with myeloid sarcoma of the testis.