Myeloid sarcoma is a rare manifestation of acute myeloid leukaemia where myeloid blasts form a nodule, often in the mediastinum but can occur at any extramedullar site.
The disease is a rare manifestation of AML and therefore occurs at a similar age range.
Patients may present with mass effect related to the tumour, occasionally prior to clinical presentation with AML; this nearly always follows shortly thereafter.
Tumour/Normal Tissue Features
Macroscopically the tumour forms a mass. Microscopically, the tumour comprises myeloblasts and promyelocytes in the most common form (granulocytic sarcoma). Other forms may consist of myeloblasts only.
It seems to occur more commonly from myeloid leukaemia that has translocation of chromosomes 8 and 21.