Myeloid sarcoma: An overview

Myeloid Sarcoma (MS) is a high grade, hematological malignancy defined as an extramedullary tumor mass of myeloid blasts with or without maturation that effaces tissue architecture. It is a highly heterogenous condition that represents a variety of myeloid neoplasms. This heterogeneity of MS, together with its rarity, have greatly hampered our understanding of the condition. Diagnosis requires tumor biopsy, which should be accompanied by bone marrow evaluation for medullary disease. It is presently recommended that MS be treated similar to AML. Additionally, ablative radiotherapy and novel targeted therapies may also be beneficial. Genetic profiling has identified recurrent genetic abnormalities including gene mutations associated with MS, supporting its etiology similar to AML. However, the mechanisms by which MS homes to specific organs is unclear. This review provides an overview of pathogenesis, pathological and genetic findings, treatment, and prognosis. Improving the management and outcomes of MS patients requires a better understanding of its pathogenesis and its response to various therapeutic approaches.

Myeloid sarcoma with NPM1 mutation may be clinically and genetically distinct from AML with NPM1 mutation: a study from the Bone Marrow Pathology Group

Myeloid sarcoma (MS) is currently considered equivalent to de novo acute myeloid leukemia (AML); however, the relationship between these entities is poorly understood. This retrospective multi-institutional cohort study compared 43 MS with NPM1 mutation to 106 AML with NPM1 mutation. Compared to AML, MS had more frequent cytogenetic abnormalities including complex karyotype (p = .009 and p = .007, respectively) and was enriched in mutations of genes involved in histone modification, including ASXL1 (p = .007 and p = .008, respectively). AML harbored a higher average number of gene mutations (p = .002) including more frequent PTPN11 mutations (p < .001) and mutations of DNA-methylating genes including DNMT3A and IDH1 (both p < .001). MS had significantly shorter overall survival (OS) than AML (median OS: 44.9 vs. 93.2 months, respectively, p = .037). MS with NPM1 mutation has a unique genetic landscape, and poorer OS, compared to AML with NPM1 mutation.

Impact of a Modified HistoGel Method for Processing Endocervical Curettage Specimens on Diagnostic Yield

OBJECTIVES

Endocervical curettage (ECC) specimens may be limited by scant tissue. We evaluated whether a cellular concentration processing method could improve their diagnostic quality.

METHODS

Between October 2018 and June 2019, ECC specimens were assigned chronologically to one of two groups: nonconcentrated ECC (NECC) or concentrated ECC (CECC). NECC specimens underwent routine histologic processing. CECC specimens were processed using a published HistoGel-based cell block method. We reviewed diagnoses for ECCs, concurrent cervical biopsies and/or loop electrosurgical excision procedures (LEEPs), and preceding Papanicolaou (Pap) smears. We performed multivariate logistic regression analyses to evaluate the impact of processing method on ECC adequacy and discordance between Pap smear and worst tissue diagnoses.

RESULTS

NECC and CECC adequacy was 88.2% and 84.7% (P = .06). ECC adequacy was greater if concurrent biopsy/LEEP was performed (odds ratio [OR] = 1.76, P < .01). Discordance between Pap smear and worst tissue diagnoses was 9.5% and 13.3% (P = .04) for cases with NECC and CECC processing, although processing method was not significant in multivariate analysis (OR = 0.74, P = .11). Adequate ECC sampling and concurrent biopsy/LEEP were independently associated with concordance between Pap smear and worst tissue diagnosis (OR = 0.46, P < .01 and OR = 0.65, P = .02).

CONCLUSIONS

ECC processing method did not significantly affect either specimen adequacy (P = .06) or diagnostic discordance (P = .11) when controlled for other factors.