Myeloid Sarcoma in Myelodysplastic Syndrome : Review

Introduction: Myeloid sarcoma (MS), Granulocytic sarcoma (GS), or Chloroma is defined in the World Health Organization (WHO) classification as a tumor mass consisting of myoblasts with or without maturation and involving any anatomic site other than the bone marrow. Myeloid sarcoma usually founds either concurrently or following a previously recognized (acute myeloid leukemia) AML. Common sites of occurrence are skin, sinuses, bone, and others. It rarely involves the central nervous system and Spinal cord involvement usually manifests as epidural mass causing cord compression.

Methodology: A literature search was performed for English language articles using PubMed, Scopus, and Google Scholar, for any date up to June 2022. The following keywords were used "MDS and/or Myeloid sarcoma (granulocytic sarcoma) or Chloroma." Search results were initially reviewed by title and abstract, and articles were selected for more in-depth analysis if deemed relevant. Pertinent articles were examined in-depth for this report.

Results: We reviewed 73 articles from the year 1981 to 2021. Males were almost twice the females, with 46 males and 24 females with aThe median age was 67 years. Median complete blood count (CBC) showed hemoglobin (Hgb) of 9.2 g/dL, white blood cells (WBC) of 7.45 x10⁹/L, and platelets of 82 x10⁹/L. The different subtypes of MDS reported were; 11 (15%) patients with CMML, 3 (4%) with del 5q-, and 1 patient had MDS with hypoblastic bone marrow. The most common site of involvement was the skin in 33 (45%) of the patients, followed by lymph nodes in 10 (13%) patients, spinal/para-spinal in 8 (10%) patients, face or ear-nose-throat (ENT) in 7 (9%) patients, Gastrointestinal area I in 6 (8%) patients. Other involved areas include prostate in three patients, bladder in three patients, breast in three patients, brain in two patients, and testicular, bronchial, mediastinum, and vaginal involvement in one patient each (some patients have more than one site involved). Twenty-six (35%) patients were treated with chemotherapy alone or in combination with surgery or radiotherapy, 14 (19%) patients underwent local surgical resection, while 12 (16%) patients received radiation therapy alone or in combination. In addition, two patients underwent an allogeneic bone marrow transplant. On the other hand, 17 (23%) patients did not receive any treatment. Eighteen (24%) patients progressed to acute myeloid leukemia (AML). For overall survival, 35 (47%) patients died.

Conclusion: Myeloid sarcoma (MS) is rare with MDS. However, it should be thought of and kept in mind as a differential diagnosis with an initial investigation by imaging and biopsy. Multiple sites can be involved with or without the involvement of the bone marrow with a considerable number of patients progressing to to AML and die. There are no guidelines for treatment up to now. The use of new MDS risk stratification scores, along with cytogenetics and mutations profile, might help to predict who is at risk in the future.

No relevant conflicts of interest to declare.