Barometric indications of a resisting aether

Abstract

Myeloid sarcoma of the breast is a rare manifestation of acute myeloid leukaemia (AML). This report describes a patient who was diagnosed with AML FAB M2. Molecular analysis showed evidence of an <i>NPM1</i> mutation (subtype A) and internal tandem duplications of the <i>FLT3</i> gene (<i>FLT3</i>-ITD). Eight months after allogeneic stem cell transplantation, the patient developed a palpable mass in the left breast initially suspected as breast carcinoma. Core needle biopsy of the lesion resulted in diagnosis of myeloid sarcoma. Molecular analysis of formalin-fixed specimens of the breast tumour confirmed the known <i>FLT3</i> and <i>NPM1</i> gene mutations. Immunohistochemically, an aberrant cytoplasmic staining pattern for <i>NPM1</i> and overexpression of <i>FLT3</i> were demonstrated. The myeloid sarcoma showed complete transient resolution following treatment with the kinase inhibitor sorafenib. However, the patient developed bone marrow relapse and died in fatal cerebral haemorrhage 1 year after initial diagnosis of AML. In summary, combined molecular and immunohistochemical examination of <i>NPM1</i> and <i>FLT3</i> is helpful in the diagnosis of extramedullary manifestations of AML in core needle biopsies.