| Abstract|| |
The term, "myeloid sarcoma" refers to an extramedullary collection of immature myeloid cells. Rarely may it precede peripheral blood or bone marrow involvement, presenting as a diagnostic challenge. We report here a case of myeloid sarcoma in a 45 year-old man, who presented with a painful right orbital swelling of one month's duration. Fine needle aspiration cytology (FNAC) was performed and a diagnosis of myeloid sarcoma was offered. Subsequently, a complete blood count revealed 60% blasts in the peripheral blood and a diagnosis of acute myeloid leukemia (AML) was confirmed on bone marrow examination. This case is being documented to emphasise the utility of FNAC in making the correct diagnosis of this entity in a case of unsuspected AML.
Keywords: AML; Auer rod; FNAC; myeloid sarcoma; orbit.
|How to cite this article:|
Tangri R, Prakash N, Khurana A. Myeloid sarcoma of the orbit. J Cytol 2008;25:111-2
| Introduction|| |
Myeloid sarcoma (MS) is a tumor mass of myeloblasts or immature myeloid cells occurring in an extramedullary site or in bone.  It occurs in patients of acute myeloid leukemia (AML) as well as in patients with myeloproliferative and myelodysplastic disorders. These may present as diagnostic dilemmas where a prior diagnosis of leukemia is not established. The tumorous masses can occur anywhere in the body and have to be differentiated from other causes of solid collections such as carcinomas, lymphomas, or infectious processes. In this report, we describe a case that presented primarily with orbital swelling, and was cytologically diagnosed as myeloid sarcoma.
| Case Report|| |
A 45 year-old man presented with a gradually increasing swelling of one month's duration in the right orbit which was associated with pain and redness of the eye. He also complained of hoarsening of his voice and fever. On examination, the mass was found to be firm, measuring 10 cm across its largest diameter, and was found to involve the periorbital area and forehead. The patient was referred for fine needle aspiration cytology (FNAC), which yielded a hemorrhagic aspirate. Giemsa-stained smears showed scattered, singly placed, malignant, round cells with a high nuclear-cytoplasmic ratio, prominent nucleoli, scanty basophilic cytoplasm, and pink cytoplasmic granules in a few cells [Figure 1]. After a more careful and intense search, Auer rods More Details were observed in a few cells [Figure 2]. Myeloperoxidase (MPO) staining confirmed the myeloid nature of these cells [Figure 3] and a diagnosis of MS was offered. A complete blood count revealed 60% blasts in the peripheral blood and a diagnosis of AML M1 was made on bone marrow examination.
| Discussion|| |
The term, "myeloid sarcoma" refers to the presence of tumorous collections of immature myeloid cells at sites other than the bone marrow. Originally, the term, "chloroma" was applied to these tumors because of their characteristic green color. As the tumor mass are not always green in color, they are also sometimes known as "granulocytic sarcomas" and are now termed as "myeloid sarcoma".  The most common sites of occurrence are the subperiosteal bone structures of the skull, paranasal sinuses, sternum, ribs, vertebrae, and the pelvis.  The peripheral smear and subsequent bone marrow examination can confirm the diagnosis in almost all the cases, except those where extramedullary involvement precedes the leukemic presentation. In these cases, cytological preparations give us better morphological detail of blasts; the identification of Auer rods and MPO stain can help clinch the diagnosis of an undetected AML. Our case report demonstrates the clinical utility and accuracy of FNAC in making the diagnosis of MS from an extramedullary site. The visualization of an Auer rod is possible only in cytological material, so it would be much easier to make diagnoses based on FNAC and imprint smears rather than in histological sections. The work-up of these masses can be aided by the use of cytochemistry (MPO, Sudan Black, nonspecific esterase) and immunophenotyping.
The correct diagnosis of MS is a must for adequate therapy. The treatment is similar to that for AML, even in cases of isolated tumors with no blood or bone marrow involvement. Radiotherapy has been proposed in association with chemotherapy for patients with massive tumors. 
In patients with AML, the progression of myeloid sarcoma has the same prognosis as the underlying leukemia. The patients with an AML associated with t (8;21) and presenting with myeloid sarcoma have a low rate of complete remission, and overall survival is poor. This appears to be in contrast to the better prognosis generally seen in AML with t (8;21). In patients with chronic myeloproliferative and myelodysplastic syndromes, myeloid sarcoma defines a blastic transformation often associated with a short survival. ,
In conclusion, we may state that the present case was cytologically evaluated and interpreted as MS. The correct recognition of this entity and differentiating it from other mimics are crucial to proper patient management and appropriate follow-up.
| References|| |
|1.||Brunning RD, Matutes E, Harris NL, Flandrin G, Vardiman J, Bennett J et al . Acute myeloid leukemias. In: World Health Organization classification of tumors. Pathology and genetics of tumours of hematopoietic and lymphoid tissues. Lyon: IARC Press; 2001. p. 75-107. |
|2.||Wiernik PH, Serpick AA. Granulocytic sarcoma (Chloroma). Blood 1970;35:361-9. |
|3.||Imrie KR, Kovacs MJ, Selby D, Lipton J, Patterson BJ, Pantalony D, et al . Isolated chloroma: The effect of early antileukemic therapy. Ann Intern Med 1995;123:351-3. |
|4.||Byrd JC, Edenfield WJ, Shields DJ, Dawson NA. Extramedullary myeloid cell tumors in acute nonlymphocytic leukemia: A clinical review. J Clin Oncol 1995;13:1800-16. |
|5.||Byrd JC, Weiss RB, Arthur DC, Lawrence D, Baer MR, Davey F, et al . Extramedullary leukemia adversely affects hematologic complete remission rate and overall survival in patients with t(8;21)(q22;q22): Results from Cancer and Leukemia Group B 8461. J Clin Oncol 1997;15:466-75. |
98 SFS Flats Phase - 4, Ashok Vihar, Delhi - 110 052
Source of Support: None, Conflict of Interest: None
[Figure 1], [Figure 2], [Figure 3]