Granulocytic sarcoma of mesentery in acute myeloid leukemia with CBFB/MYH11 fusion gene but not inv(16) chromosome: Case report and review of literature

Myeloid sarcoma

PURPOSE OF REVIEW

Myeloid sarcoma; also known as granulocytic sarcoma and chloroma, often occurs concomitantly with AML, and rarely without bone marrow involvement. In this article, we review the recent literature on myeloid sarcoma, focusing on treatment approach for this rare disease, and addressing the prognostic and therapeutic role of molecular and cytogenetic aberrations.

RECENT FINDINGS

Molecular testing and cytogenetics are important adjunct to conventional diagnostic methods. The significance of cytogenetic and molecular abnormalities in myeloid sarcoma is not completely established, but testing for targetable mutations on myeloid sarcoma cells is feasible, imperative, and may guide treatment decisions. Outcomes in myeloid sarcoma largely depend on the background of its development. Almost all patients with myeloid sarcoma eventually develop AML typically in a short period after its diagnosis; therefore, remission induction treatment using AML type chemotherapy has been the standard of care. Postremission therapy is controversial; allogenic SCT, radiotherapy or consolidation chemotherapy should be considered according to patient risk.

SUMMARY

Further research is required to understand the nature of myeloid sarcoma, and inclusion of patients with this condition in clinical trials should be considered to better identify the best diagnostic, prognostic, and therapeutic approach in managing this rare disease.

Myeloid Sarcoma With CBFB-MYH11 Fusion (inv(16) or t(16;16)) Prevails in the Abdomen

OBJECTIVES

Myeloid sarcoma with CBFB-MYH11 fusion may be enriched in abdominal sites. The clinicopathologic features of 11 cases are reported.

METHODS

We collected clinical features, morphology, immunophenotype, and bone marrow (BM) involvement of myeloid sarcoma cases with CBFB-MYH11 fusion.

RESULTS

Eleven of 29 total myeloid sarcoma cases were CBFB-MYH11 positive and all 11 involved abdominal sites. The blastic infiltrate was associated with eosinophils in four of 11 cases and plasmacytoid dendritic cell (pDC) nodules in four of six cases. CD34, CD117, and myeloperoxidase were expressed in eight of nine, 10 of 10, and 10 of 10 cases, respectively. Ten of 10 cases showed no BM involvement.

CONCLUSIONS

Our current series, combined with a literature review, identifies a compelling series of 31 (94%) of 33 cases of myeloid sarcoma with CBFB-MYH11 fusion showing a marked predilection for abdominal sites. In addition, the lack of obvious associated eosinophils, presence of pDC nodules, and lack of concurrent BM involvement suggest that "myeloid sarcoma with CBFB-MYH11 fusion" may represent a unique phenomenon.

Leukemia in gastrointestinal organs as cause of treatment failure: 378 cases analyzed

Leukemia growing as tumors in gastrointestinal organs is an under-investigated cause of treatment failure and death. These present with symptoms often mistaken for common toxicities but may grow large before symptoms. To synthesize experience available only in case reports, 378 were analyzed. Invasive and metastatic behavior typical of solid GI tumors was revealed even when marrow was uninvolved. Within 3 months of diagnosis, 33% had died, 47% within 1 year. Survivals of 4 to 18 years after involvement suggest cure is possible. Evidence is presented that combined local and systemic therapy has successfully treated GI leukemic tumors when identified early.

Peritoneal Myeloid Sarcoma in a Patient Treated for a Testicular Seminoma

BACKGROUND Myeloid sarcoma is a rare extramedullary soft tissue neoplasm composed of myeloblastic cells, usually associated to hematologic tumor disorders and a poor prognosis. Its diagnosis is very difficult as radiological images are not specific. Histology and immunohistochemistry are necessary for an accurate diagnosis. CASE REPORT We report the case of 46-year-old, Caucasian, non-smoker male, treated in 2014 by orchiectomy and systemic chemotherapy for a stage IIB testicular seminoma. Considering the rapid increase of lactate dehydrogenase (LDH) levels without any evident medical reason, a computed tomography/positron emission tomography (CT/PET) scan was performed and revealing a diffuse, nodular, peritoneal tumor infiltration associated with multiple mesenteric and mediastinal adenopathies. Laparoscopy confirmed a diffuse tumor infiltration of the peritoneum. Histology and immunohistochemistry were consisted with the diagnosis of a myeloid monoblastic sarcoma. Cytology of bone marrow documented an monocytic acute myeloid leukemia. The patient started a systemic induction chemotherapy with high dose cytarabine and idarubicin that was complicated by an infectious pneumonia and colitis, and a grade IV thrombocytopenia leading to a brain subdural hemorrhage and quickly to patient's death. CONCLUSIONS We describe a rare, peritoneal, myeloid sarcoma in a young patient who had been treated by systemic chemotherapy for testicular seminoma 4 years earlier. The patient was clinically asymptomatic and presented only elevated LDH levels without any evident clinical reason. Considering the persistence of this biochemical abnormality, more investigations were performed leading to a diagnosis of peritoneal myeloid sarcoma associated with monocytic acute myeloid leukemia, probably secondary to the past chemotherapy.

Decrease of TET2 expression and increase of 5-hmC levels in myeloid sarcomas

BACKGROUND

Myeloid sarcoma is a tumor mass that consists of myeloblasts or immature myeloid cells at an extramedullary site. Pathological diagnosis is very difficult based on morphology if systemic signs of disease are absent. The subtype of myeloid sarcoma is also minimally identifiable in the histological picture.

FINDINGS

We investigated 18 paraffin-embedded myeloid sarcoma samples, and our immunohistochemical data confirmed the relevance of some key markers for the diagnosis and subclassification of myeloid sarcoma. CD34 was found as a marker in 67% of the myeloid sarcoma cases, and CD34 was positive in all immature types of myeloid sarcoma. CD68 was found in 83% of the myeloid sarcoma cases, but CD68 was most identified in the differentiated type of myeloid sarcoma. Myeloperoxidase (MPO) was positive in all myeloid sarcomas. Notably, the reactivity of MPO in the blastic subtype was much lower in myeloid sarcomas. CD117 reactivity was found in 67% of myeloid sarcomas. Ten-eleven translocation 2 (TET2) protein exhibited significant negative reactivity in 88% of the cases, and 5-methylcytosine (5-hmC) was significantly positive in the nucleus in 100% of the cases.

CONCLUSIONS

Our findings indicated that an immunohistochemical panel that included MPO, CD68 and CD34 could be used for the detection of blastic, differentiated and immature types of myeloid sarcoma. Changes in novel epigenetic regulators, including the loss of TET2 and gain of 5-hmC, as characteristics of myeloid malignancies may be useful novel markers of myeloid sarcoma.

Extramedullary Manifestations of Myeloid Neoplasms

OBJECTIVES

This session of the 2013 Society of Hematopathology/European Association for Haematopathology workshop focused on extramedullary manifestations of myeloid neoplasms.

METHODS

We divided the submitted cases into four subgroups: (1) isolated myeloid sarcoma (MS); (2) MS with concurrent acute myeloid leukemia (AML), with a focus on karyotypic and molecular findings; (3) extramedullary relapse of AML, including relapse in the posttransplant setting; and (4) blast phase/transformation of a myeloproliferative neoplasm or chronic myelomonocytic leukemia.

RESULTS

Establishing a diagnosis of isolated MS requires a high index of suspicion and use of immunophenotypic methods. Recurrent cytogenetic abnormalities or gene mutations that occur in MS mirror those known to occur in AML.

CONCLUSIONS

In the era of targeted therapy and sophisticated risk stratification, every attempt must be made to perform a complete workup on MS cases (or concurrent AML) since the diagnosis of MS, in itself, is no longer adequate for patient management. Cases of blastic plasmacytoid dendritic cell neoplasm were also included and discussed in this session.

Primary oral myeloid sarcoma: Report of a case

Myeloid sarcoma is defined as a tumor mass of immature myeloid cells that may be observed in a variety of locations including bone, skin, lymph nodes and soft tissues. However, oral involvement of myeloid sarcoma is extremely rare. These tumors are considered as specific lesions of acute myeloid leukemia. We present a case of a myeloid sarcoma of the upper vestibular gingiva in a 29-year-old woman who has no hematologic disease history. Multiple metastases were found in floor of the nasal cavity, left breast, and left lacrimal gland 12 months after primary diagnosis.

Clinical significance of granulocytic sarcoma in adult patients with acute myeloid leukemia

To investigate the clinical significance of granulocytic sarcoma (GS) in adults with acute myeloid leukemia (AML), 434 consecutive patients with AML were analyzed retrospectively. Forty-five patients (10.4%) with GS at diagnosis were younger (P < 0.001), presented with higher white blood cell counts (P = 0.03) and were more likely to conform to French-American-British M4 (P = 0.001) and M5 (P = 0.045) classifications than those without GS. In contrast, no significant difference in frequency of cytogenetic abnormalities was found between the GS and non-GS groups. Treatment outcomes in 260 patients (40 with GS) who underwent intensive chemotherapy, excluding patients with acute promyelocytic leukemia, were investigated. Complete remission rates did not differ significantly between the GS and non-GS groups (75.0% vs 79.1%; P = 0.192, respectively) or the 5-year overall survival (OS) rates (39.9% vs 38.7%; P = 0.749, respectively). However, the GS group had a significantly higher relapse rate than the non-GS group (74.2% vs 55.3%; P = 0.048) and a significantly lower 5-year disease-free survival rate (8.2% vs 25.7%, respectively; P = 0.005). When considered together with the results of multivariate analysis, which identified the presence of GS as an independent predictor for disease-free survival time, these findings indicate that GS might identify a high-risk subset of patients with AML.

Isolated granulocytic sarcoma of the pancreas: a tricky diagnostic for primary pancreatic extramedullary acute myeloid leukemia

We report two clinical cases of primary granulocytic sarcoma of the pancreas that were diagnosed on the surgical specimen. Atypical clinical and morphological presentations may have lead to pretherapeutic biopsies of the pancreatic mass in order to indicate primary chemotherapy. Literature review of this rare clinical presentation may help physicians to anticipate diagnostic and therapeutic strategies.

Clinical implications of acute myeloid leukemia presenting as myeloid sarcoma

In this retrospective study, we aim to analyze the characteristics, treatments, and overall survival of all patients presenting with isolated myeloid sarcoma (MS) or MS with concomitant acute myeloid leukemia (AML) compared with all patients with AML, treated during the same period. We identified patients with AML with or without MS at diagnosis, presenting to our medical center between the years 1990 and 2005. There was no statistically significant difference between the groups regarding gender, age, cytogenetic risk groups, rate of complete remission, number of cycles of chemotherapy needed to achieve complete remission, and rate of first relapse. The time to death in the MS group was not significantly different (p = 0.60) from the AML group, and radiotherapy did not affect the median time to death. Transplantation prolonged survival in both groups (p = 0.018 and p < 0.0001, respectively). Patients with MS at diagnosis might benefit from upfront aggressive treatment with hematopoietic stem cell transplantation.

Granulocytic sarcoma of abdomen in acute myeloid leukemia patient with inv(16) and t(6;17) abnormal chromosome: case report and review of literature

Granulocytic sarcoma (GS) is composed of immature granulocytic precursors and is usually found in acute myeloid leukemia (AML) patients with t(8;21). Inv(16) is rarely associated with GS comparing with t(8;21) leukemia. Here we describe an abdominal GS patient in AML-M2 with acquired translocation between chromosomes 6 and 17 and inv (16). We have also summarized 20 reported GS cases with inv(16) and found that chloroma was most often found in abdominal lesions. Intestine maybe a tissue specific target for the expression of inv(16) leukemia. Complete physical examination and molecular diagnosis are necessary for AML patients to benefit from the diagnosis and therapeutic strategy.

Detection of the CBFB/MYH11 fusion gene in de novo acute myeloid leukemia (AML): A single-institution study of 224 Japanese AML patients

The cytogenetic findings in acute myeloid leukemia (AML) are a powerful prognostic indicator. Among these abnormalities, the World Health Organization has classified inv(16)(p13q22), which is closely associated with the M4E classification in the French-American-British system, as indicating a good-risk AML. However, this chromosomal abnormality can often be difficult to detect. In this study, we used RT-PCR and FISH analysis to examine 224 Japanese adult de novo AML patients for the presence of the CBFB/MYH11 fusion transcript at the time of diagnosis. The CBFB/MYH11 fusion gene was detected in 17 patients (7.6%): eight patients had the inv(16) chromosome and in all of them it was M4E; nine patients did not have abnormalities in chromosome 16. AML with the CBFB/MYH11 fusion gene but without inv(16) was found in M2, M4, and M5, but not in M4E patients. There were no statistically significant differences in the clinical features of patients with the inv(16) and those with the cryptic inv(16) chromosome. These results indicate that even if eosinophilia is not found, molecular screening for CBFB/MYH11 fusion gene should be performed in all AML patients at the time of diagnosis to help guide disease management.

Cytogenetics detects infiltrations of a primary cutaneous acute myeloid leukemia to the kidney

Extramedullary manifestations of acute myeloid leukemia (AML) are rare and commonly involve one tissue. We report of a cutaneous acute myelomonocytic leukemia infiltrating the kidney next to the skin. A 61-year-old female patient with complex karyotype cutaneous AML FAB M4 underwent abdominal computed tomography scans. A lesion in her left kidney appeared suspicious of renal carcinoma as confirmed by histology. However, fluorescence in situ hybridization cytogenetics revealed a chromosome 11q23 abnormality in the nephrectomy specimen, which also appeared in the leukemic blasts of skin and bone marrow. Closer histomorphologic workup revealed an infiltration of the kidney with leukemia. This case report illustrates how modern diagnostic procedures can help to reveal rare sites of disease.