Myeloid sarcoma in children – diagnostic and therapeutic difficulties

Abstract

Myeloid sarcoma (MS) is a malignant extramedullary tumour, which consists of immature cells of myeloid origin. It may occur de novo, concurrently or precede the diagnosis of acute myeloid leukemia (AML), myelodysplastic syndrome (MDS) or chronic myeloid leukemia (CML). MS can also be a manifestation of the relapse of the disease. The more frequent sites of involvement are the skin, orbit, bone, periosteum, lymph nodes, gastrointestinal tract, soft tissue, central nervous system and testis. Because of its different localization and symptoms, and the lack of diagnostics algorithm, myeloid sarcoma is a real diagnostic challenge, in particular in patients without initial bone marrow involvement. The correct diagnosis of MS is important for adequate therapy, which is often delayed because of a high misdiagnosis rate. In the paper, the role of immunohistochemistry, cytogenetic and molecular genetic analyses is emphasized as well as the breadth of unclear aspects of this disorder in children.

Progressive cranial neuropathy and uterine involvement in myeloid sarcoma

“…The first issue of interest is the pathological diagnosis. Myeloid sarcoma is a rare extramedullary tumour of immature myeloid cells that is most commonly seen in patients with acute myeloid leukaemia (AML) 1. Nonetheless, myeloid sarcoma can also occur, as in the present case, in the absence of blood or bone marrow involvement.…”

RUNX1-RUNX1T1-positive acute myeloid leukaemia presenting as bilateral proptosis and multiple cranial nerve palsy

“…Incidence of extramedullary involvement in paediatric AML ranges from 6.7% to 23.3% 4. An extramedullary myeloid tumour is referred to by varying nomenclature including myeloid sarcoma (MS), granulocytic sarcoma and chloroma 1.…”

“…An extramedullary myeloid tumour is referred to by varying nomenclature including myeloid sarcoma (MS), granulocytic sarcoma and chloroma 1. Skin and orbit are the most common sites of manifestation of paediatric MS, in addition to bones, lymph nodes, gastrointestinal tract and CNS 4. CNS involvement in AML can occur in 6%–29% of children with AML 5.…”

A New Complex Karyotype Involving a <b><i>KMT2A</i></b>-r Variant Three-Way Translocation in a Rare Clinical Presentation of a Pediatric Patient with Acute Myeloid Leukemia

“…This is more common in children than in adults (accounting for 40 vs. 2-5% of cancers in these respective populations) and is associated with different subtypes of AML, including megakaryoblastic and monoblastic subtypes. In patients with the RUNX1-RUNX1T1 gene fusion, orbital myeloid sarcoma is relatively common, whereas patients with the CBFB-MYH11 fusion have more diverse patterns, including involvement of the central nervous system [Yilmaz et al, 2013;Samborska et al, 2016]. KMT2A-ELL fusions have been associated with myeloid sarcomas in infants, being rare in older ages, but with no specific site of disease involvement [de Rooij et al, 2015;Panagopoulos et al, 2016;Samborska et al, 2016].…”

“…In patients with the RUNX1-RUNX1T1 gene fusion, orbital myeloid sarcoma is relatively common, whereas patients with the CBFB-MYH11 fusion have more diverse patterns, including involvement of the central nervous system [Yilmaz et al, 2013;Samborska et al, 2016]. KMT2A-ELL fusions have been associated with myeloid sarcomas in infants, being rare in older ages, but with no specific site of disease involvement [de Rooij et al, 2015;Panagopoulos et al, 2016;Samborska et al, 2016]. Because myeloid sarcoma occurs in association with karyotypes that reflect favorable outcomes, it is unlikely to be an independent prognostic indicator.…”