- Human pathology

Home > D. General pathology > Blood and immunity > myeloid sarcoma

myeloid sarcoma

Friday 5 December 2003

chloroma, extramedullary myeloid tumor, granulocytic sarcoma

Definition: Myeloid sarcoma (MS) is a neoplasm of immature granulocytes, monocytes, or both involving any extramedullary site.

Extramedullary accumulation of myeloblasts or immature myeloid cells form tumors called myeloid sarcoma in the WHO classification. Such tumors develop in lymphoid organs, bone (skull, orbit, etc.), skin, soft tissue, various mucosae and organs, and the CNS. The correct diagnosis of MS is important for adequate therapy, which is often delayed because of a high misdiagnosis rate.

They may precede or occur concurrently with acute myeloid leukemia, or reveal blastic transformation of chronic myeloproliferative disorders or myelodysplastic syndromes. They may also reveal relapses in treated patients.


- Myeloid sarcoma: myelolasts, fine chromatin, prom nucleoli. CD45, MPO, CD43, lysozyme, CD117+. Variable CD34. monocytic: CD68+.

Microscopical synopsis

Histologically, 50% of the tumors are of the blastic type, 43.5% either monoblastic or myelomonocytic and 6.5% corresponded to different histotypes. Foci of plasmacytoid monocyte differentiation can be observed in intestinal cases carrying inv(16).

- diffuse infiltrate made up of medium-to-large cells


- CD43 (100%)
- lysozyme (100%)

CD68/KP1 is the most commonly expressed marker (100%), followed by myeloperoxidase (83.6%), CD117 (80.4%), CD99 (54.3%), CD68/PG-M1 (51%), CD34 (43.4%), terminal-deoxy-nucleotidyl-transferase (31.5%), CD56 (13%), CD61/linker for activation of T cells (2.2%), CD30 (2.2%) and CD4 (1.1%).

An immunohistochemical panel including CD43, lysozyme, myeloperoxidase (MPO), CD68 (or CD163), CD117, CD3 and CD20 can successfully identify the vast majority of MS variants in formalin-fixed paraffin-embedded tissue sections. (17974004)

- granulocytic myeloperoxidase (MPO+, CD 68+ [KP1+/-, PGM1-] lysozyme+, CD 34+/-)
- monoblastic (MPO-, CD 68+, [KP1+, PGM1+] lysozyme+, CD 34-)
- myelomonoblastic (MPO-, CD 68+, [KP1+, PGM1+] lysozyme+, CD 34-)
- megakaryoblastic (positivity for factor VIII, CD 61, CD 31).

- CD 43
- CD 7
- CD 79a
- CD 56 ( t[8;21])

- CD 99
- CD 117


De novo MS show a normal karyotype, monoblastic differentiation, and lack of CD34. (17974004)

The most common chromosomal abnormalities in MS associated with a hematopoietic disorder were trisomy 8 (18%) and inv(16) (18%). (17974004)

Chromosomal aberrations are detected in about 54% of cases: monosomy 7 (10.8%), trisomy 8 (10.4%) and mixed lineage leukemia-splitting (8.5%) were the commonest abnormalities, whereas t(8;21) was rare (2.2%).

- trisomy 8 (17974004, 12437650, 11697634)
- near-tetraploid karyotype with an isochromosome 17q (18262059)


The behavior is irrespective of presentation, age, sex, phenotype and cytogenetics. Most if not all, long survivors received bone-marrow transplantation.


- Bettio D, Venci A, Sarina B. Near-tetraploid karyotype with an isochromosome 17q as the sole structural chromosomal rearrangement in a case of testicular granulocytic sarcoma. Cancer Genet Cytogenet. 2008 Feb;181(1):69-71. PMID: 18262059

- Alexiev BA, Wang W, Ning Y, Chumsri S, Gojo I, Rodgers WH, Stass SA, Zhao XF. Myeloid sarcomas: a histologic, immunohistochemical, and cytogenetic study. Diagn Pathol. 2007 Oct 31;2:42. PMID: 17974004

- Pileri SA, Ascani S, Cox MC, Campidelli C, Bacci F, Piccioli M, Piccaluga PP, Agostinelli C, Asioli S, Novero D, Bisceglia M, Ponzoni M, Gentile A, Rinaldi P, Franco V, Vincelli D, Pileri A Jr, Gasbarra R, Falini B, Zinzani PL, Baccarani M. Myeloid sarcoma: clinico-pathologic, phenotypic and cytogenetic analysis of 92 adult patients. Leukemia. 2007 Feb;21(2):340-50. PMID: 17170724

- Audouin J, Comperat E, Le Tourneau A, Camilleri-Broet S, Adida C, Molina T, Diebold J. Myeloid sarcoma: clinical and morphologic criteria useful for diagnosis. Int J Surg Pathol. 2003 Oct;11(4):271-82. PMID: 14615822

- Fujii N, Ikeda K, Takahashi N, Kojima K, Kobayashi Y, Ashiba A, Takenaka K, Fukuda S, Shinagawa K, Ishimaru F, Niiya K, Miura I, Tanimoto M, Harada M. Multilineage involvement in hypereosinophilic syndrome terminating in granulocytic sarcoma and leukaemic transformation with trisomy 8. Br J Haematol. 2002 Dec;119(3):716-9. PMID: 12437650

- Somjee S, Borker A, Gardner R, Velez MC. Multiple granulocytic sarcomas in acute myeloblastic leukemia with simultaneous occurrence of t(8:21) and trisomy 8. Leuk Lymphoma. 2001 Sep-Oct;42(5):1139-44. PMID: 11697634