myeloid sarcoma

A rare cause
of acute paraplegia: granulocytic sarcoma. T1-weighted sagittal MRI showed: Extensive epidural lesion extending from D4 to D10, isointense, compressing the spinal cord, associated to a diffuse low signal intensity of the vertebral bone marrow (tumoral infiltration).
www.eurorad.org • CC by-nc-sa-4.0
A rare cause
of acute paraplegia: granulocytic sarcoma. T2-weighted sagittal MRI showed: Extensive epidural lesion extending from D4 to D10, isointense, compressing the spinal cord.
www.eurorad.org • CC by-nc-sa-4.0
Granulocytic
sarcoma of the brain in an adult with chronic myeloid leukaemia. Unenhanced brain CT images. Multiple spontaneously hyperdense masses with peritumoral oedema with a supratentorial distribuition.
www.eurorad.org • CC by-nc-sa-4.0
Granulocytic
sarcoma of the brain in an adult with chronic myeloid leukaemia. Enhanced brain CT images. The masses enhances intensely and homogeneously after IV contrast administration.
www.eurorad.org • CC by-nc-sa-4.0
Granulocytic
sarcoma of the brain in an adult with chronic myeloid leukaemia. T2-weighted images. The lesions are hypointense with hyperintense surrounding oedema.
www.eurorad.org • CC by-nc-sa-4.0
Granulocytic
sarcoma of the brain in an adult with chronic myeloid leukaemia. Diffusion-weighted images (images on the left) and ADC maps (on the right). The lesions show minimal restriction to diffusion with a peripheral hyperintense halo where diffusion is facilitated due to the surrounding vasogenic oedema.
www.eurorad.org • CC by-nc-sa-4.0
Epidural
spinal cord compression as initial clinical presentation of an acute myeloid leukaemia: case report and literature review. Spine MRI showing spinal cord compression at T4-T9 level by posterior epidural mass. a Sagittal view showing a T4T9 posterior mass which is isointense on T2 weighted sequence. b Sagittal view T1 sequence showing a hypointense T4T9 posterior lésion well demarcated from the dura. c Sagittal view showing a contrast enhancement of the T4-T9 lesion. d Axial view: The lesion is hypointense on T1 weighted sequence. e Axial view: The lesion is isointense on T2 sequence at the level of T5. f Axial view showing the enhancing lesion at the level of T5 wth a good demarcation from the dura
cnjournal.biomedcentral.com • CC-by-4.0
An Unusual
Cause of Dyspnoea in a Young Patient: Myeloid Sarcoma. Axial Computed tomography pulmonary angiogram (CTPA) at the level of the pulmonary trunk. There is narrowing of both main pulmonary arteries secondary to large mediastinal soft tissue mass.
www.eurorad.org • CC by-nc-sa-4.0
An Unusual
Cause of Dyspnoea in a Young Patient: Myeloid Sarcoma. CT guided biopsy of the mediastinal mass
www.eurorad.org • CC by-nc-sa-4.0
Radiopaedia • CC-by-nc-sa 3.0 • de

Myeloid sarcomas, also called granulocytic sarcomas, chloromas, or extramedullary myeloid tumors, are rare extramedullary masses comprised of myeloid precursor cells. These tumors represent a unique presentation of acute myeloid leukemia (AML), whether in isolation to, preceding, or simultaneous with bone marrow and peripheral blood disease.

Different from leukemic infiltrates, myeloid sarcomas characteristically efface the involved tissue architecture, and are recognized as a distinct entity in the WHO classification of tumors of hematopoietic and lymphoid tissues.

Epidemiology

It is more commonly seen is in children, with ~60% occurring in individuals less than 15 years of age. There is no recognized gender predilection.

Myeloid sarcoma may develop during the course of a hematologic disorder but is seen to precede the disorder in 35% of cases.

Pathology

Myeloid sarcoma lesions are composed of immature myeloid elements and therefore represent focal accumulations of leukemic cells. In contrast to its associated entities, the lesion takes the form of a solid soft tissue mass that effaces the underlying involved tissue architecture (cf. leukemic infiltrates).

They can occur with or without relation to other forms of myeloid disorders :

  • de novo: with no prior history of myeloproliferative and myelodysplastic disorders
  • simultaneously with a myeloproliferative and myelodysplastic disorder: concomitant peripheral blood and marrow involvement
  • as a relapse of a treated myeloproliferative and myelodysplastic disorder
  • as a form of blast transformation from a prior myeloproliferative neoplasm
Location

Extramedullary involvement is a defining feature.

Almost any tissue can be affected, with skin and bone being the commonest. They have been reported in the skull, face, orbit, and paranasal sinuses. Lesions have been reported in the tonsils, oral and nasal cavities and within the lacrimal, thyroid and salivary glands. The central nervous system can also be affected.

Associations

As described in the World Health Organization classification, myeloid sarcoma is considered a unique presentation, not a subtype, of acute myeloid leukemia (AML) .

As with other forms of acute myeloid leukemia, myeloid sarcoma can evolve from myelodysplastic syndromes as well as the myeloproliferative neoplasms:

Radiographic features

Exact imaging features will depend on the location and involved organ:

  • CNS manifestations of granulocytic sarcoma
  • spinal leukemia
  • head and neck manifestations of granulocytic sarcoma
  • skeletal manifestations of granulocytic sarcoma
  • abdominal manifestations of granulocytic sarcoma
  • thoracic manifestation of granulocytic sarcoma

History and etymology

  • first described by A Burns in 1811
  • termed "chloroma" in 1853 by King due to typical forms have a green color from high levels of myeloperoxidase in immature cells
  • renamed as "granulocytic sarcoma" in 1966 by Rappaport when it was demonstrated that an estimated 30% of cells do not contain myeloperoxidase, therefore, a significant proportion of cells are not green in color
  • recently preferred to be termed "myeloid sarcoma" , as several associated types of myeloid leukemia are defined by little to no granulocytic differentiation
Siehe auch:
und weiter:
Assoziationen und Differentialdiagnosen zu Myelosarkom:
Myelodysplastisches
Syndrom
Wikipedia • CC BY-SA 4.0
Akute
myeloische Leukämie
pediatricimaging.org • CC-by-nc-sa 4.0
epidurales
spinales Myelosarkom
cnjournal.biomedcentral.com • CC-by-4.0
zerebrales
Myelosarkom
www.eurorad.org • CC by-nc-sa-4.0