Granulocytic sarcoma (GS, also known as chloroma) was first discovered by Allen Burns, a British physician, in 1811. The term chloroma was first used by King to address the greenish appearance of the tumor due to myeloperoxidase. The association of the GS with acute myeloid leukemia (AML) was first recognized by Dock in 1902. GS can be classified into two categories based on its co-occurence with other malignancies. Infiltration of the tumor with myeloblasts is the main characteristic of the tumor on H&E stain. GS rises from primitive precursors of granulocytes. The disease is an extramedullary manifestation of myeloid diseases, however, it can occur as a primary disease. Aggregation of myeloblasts, promyelocytes and myelocytes outside of the bone marrow presents itself as these solid tumors. Tumors can occur at any site and can appear as green, gray, white or brown masses. GS must be differentiated from other diseases that can present as extramedullary solid tumors. All patients with GS must be evaluated for concurrent or future malignancies as GS can occur in the course of or prior to other malignancies. The prevalence of GS is approximately 2 per 1,000,000 individuals worldwide. The most important risk factor for development of GS is genetic mutations and susceptibility. Symptoms of GS may include the following: Symptoms due to mass effect such as deafness, ptosis, altered vision, intestinal obstruction, headache, neck pain, abdominal pain, and constitutional symptoms. Chemotherapy is the main stain of treatment in patients with GS. Even patients with isolated GS must receive systemic treatment to better the prognosis.
Historical Perspective
Plain radiograph of femur in a patient with GS. Courtesy of image: pathology outlines (http://www.pathologyoutlines.com/topic/bonemyeloidsarcoma.html)Granulocytic sarcoma (GS, also known as chloroma) was first discovered by Allen Burns, a British physician, in 1811 [1].
The term chloroma was first used by King to address the greenish appearance of the tumor due to myeloperoxidase.
Majority of GS tumors are found in the soft tissues such as the peritoneum, lymph nodes, CNS and skin. They are also found in bone and periosteum.
Early clinical features include weight loss, fatigue. Other manifestations of the tumor depend on its size and location.
Prognosis of GS depends on its association with other malignacies. In cases of isolated GS the prognosis is good. However, GS associated with myeloproliferative disorders has poor prognosis.
Prognosis of isolated GS with chromosome 8 abnormalities is worse than other cases of isolated GS.
Diagnosis
Diagnostic Criteria
There are no predefined criteria for diagnosis of granulocytic sarcoma.
Granulocytic sarcoma must be suspected in patients with AML or myelodysplastic syndromes. Diagnosis must be confirmed with histopathologic study of the specimen.
Symptoms
Symptoms of GS may include the following:
Symptoms due to mass effect such as deafness, ptosis, altered vision, intestinal obstruction, etc.
Headache, neck pain, abdominal pain,etc. based on the site of the tumor
Constitutional symptoms such as fever, fatigue, etc.
Physical Examination
Patients with GS can present with varying presentations.
Hyperdense/isodence to brain/muscle in CT scan without enhancement
Isointense/hyperintense on T2-weighted MRI
Isointemse/hypointense on T1-weighted MRI
Histopathologic micrograph of GS. Infiltration with myeloblasts which can be seen in the course of AML. Courtesy of image: Wikipedia (By Nephron - Own work, CC BY-SA 3.0, https://commons.wikimedia.org/w/index.php?curid=15893726)
Abdominal plain radiogram can reveal obstruction, intussusception, etc.
Echocardiogram may reveal mobile masses in any heart chamber in cases of heart involvement.
Chest radiographs can show lymph node enlargement and consolidation.
Other Diagnostic Studies
Peripheral blood smear can reveal circulating blasts.
Histopathologic analysis of GS lesions reveals high infiltration with myeloblasts.
Treatment
Medical Therapy
Chemotherapy is the main stain of treatment in patients with GS. Even patients with isolated GS must receive systemic treatment to better the prognosis.
Patients receiving cytarabine have better prognosis[4].
Patients with chemotherpeutic regimens accepted for AML had longer period of progression to AML.
Radiation can be considered as an adjunctive therapy[7].
Combination of chemotherapy and radiotherapy can be considered in patients with CNS involvement or when rapid regression of symptoms is required.
Surgery
Surgery alone is not a good treatment strategy for GS.
Surgery can be considered prior to chemotherapy in patients where debulking can better the prognosis and help with symptom relief.[8]
Surgery can also have a diagnostic role in cases where excision of the mass provides specimen for histopatjologic diagnosis.
Prevention
There are no primary preventive measures available for GS.
References
↑Burns, Allen. "Observations of surgical anatomy, in Head andNeck". London, England, Royce, 1811: 364–366.
↑Dock G, Warthin AS. "A new case of chloroma withleukemia". Trans Assoc Am Phys, 1904. 19:64: 115.
↑Rappaport H (1967). Tumors of the hematopoietic system, inAtlas of Tumor Pathology, Section III. Washington: Fascicle 8. ArmedForces Institute of Pathology. pp. 241–247.
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