Radiation Oncology/Chloroma

Chloroma

Also called Granulocytic sarcoma.

Background
References:


 * A chloroma is a rare, extramedullary tumor of immature myeloid cells.
 * Name "chloroma" coined in 1853 by King because of its green color ("A case of chloroma" Monthly J Med 1853;18:97)
 * Green color caused by the presence of myeloperoxidase.
 * The term "granulocytic sarcoma" was used by Rappaport to describe tumors of granulocytic origina. However, the term is now used more generally and applied to any tumor related to acute nonlymphocytic leukemia or myelodysplastic syndrome.

Epidemiology
References:
 * Most frequently develop in the setting of AML but can occur with CML and MDS.
 * Incidence of 2.5-9.1% in AML.
 * Most common locations: skin, soft tissue, bone, periosteum, lymph nodes.

Treatment

 * MSKCC; 2012 (1990-2010) PMID 21962486 -- "Radiation therapy for chloroma (granulocytic sarcoma)." (Bakst R, Int J Radiat Oncol Biol Phys. 2012 Apr 1;82(5):1816-22.)
 * Retrospective. 38 pts; 22 treated with RT, 16 without. RT median dose 20 Gy at 2 Gy/fx.
 * For RT pts: LC 97%. PFS (for overall disease) 39% and OS 43% at 5 yrs. 4 pts developed chloromas at other sites.
 * Conclusion: RT resulted in excellent local control and palliation of symptoms. Propose using 24 Gy in 12 fractions.


 * Stanford; 1983 (1968-1980) PMID 6575971 -- "Extramedullary lesions in non-lymphocytic leukemia: results of radiation therapy." (Chak LY, Int J Radiat Oncol Biol Phys. 1983 Aug;9(8):1173-6.)
 * 33 pts, undergoing 54 courses of RT for symptomatic extramedullary involvement of non-lymphocytic leukemia, including 23 cases of granulocytic sarcoma. A dose response was seen at > 2000 rad and > 3000 rad.
 * Conclusion: suggest 3000 rad in 15 fractions.