Unravelling chloroma: review of imaging findings

A case of relapsed acute myeloid leukemia mimicking acute otomastoiditis

Key Clinical Message

Identifying myeloid sarcoma in rare locations is a diagnostic challenge and requires careful evaluation. The optimal management of extramedullary disease requires further investigation, but tissue biopsy and a personalized approach are crucial.

Abstract

Herein, we describe an unusual case of acute myeloid leukemia presenting with an isolated involvement of the temporal bone after a complete remission of systemic disease for more than a year. The clinical, radiological, and pathological features are discussed, highlighting the importance of considering differential diagnoses and appropriate management.

Intracranial Myeloid Sarcoma Mimicking Hypertensive Intracerebral Hemorrhage

We herein report a case of intracranial myeloid sarcoma mimicking hypertensive intracerebral hemorrhage. A 71-year-old man with a history of acute myeloid leukemia was admitted with acute-onset dysarthria. A hematoma-like lesion was found on computed tomography in the left putamen. Magnetic resonance imaging (MRI) and cerebrospinal fluid cytology confirmed the diagnosis of intracranial myeloid sarcoma. The patient showed a favorable response to chemotherapy, and follow-up MRI revealed shrinkage of the tumor. Since the computed tomography findings resemble those of intracerebral hemorrhage, it is important to suspect intracranial neoplasm, particularly in cases with a history of hematologic diseases.

Muscular and hepatosplenic candidiasis in a patient with acute myeloblastic leukemia: A case report and literature review

Key Clinical Message

Muscular and subcutaneous candidiasis is a rare entity in immunocompromised patients, but it should be kept in mind when we see multiple cystic soft tissue masses in addition to target-shaped hepatosplenic lesions in neutropenic patients. US and MRI are useful imaging modalities for the diagnosis and follow-up of these patients.

Abstract

Soft tissue candidiasis is an opportunistic infection in immunocompromised patients and must always be diagnosed and treated as soon as possible. In this case report, the patient is a 14-year-old boy with acute myeloid leukemia M3-type who presented with numerous soft tissue and hepatosplenic candidal abscesses.

Paraplegia as a Rare Clinical Presentation of Relapsed Acute Myeloid Leukemia

Myeloid sarcoma, also known as granulocytic sarcoma or chloroma, is an extra-medullary accumulation of malignant myeloid blast cells, leading to a solid tumor formation. Herein, we report a rare presentation of a case with acute myeloid leukemia (AML), whose disease relapse was clinically evident as acute flaccid paraplegia with a certain sensory level. On thoracic spine magnetic resonance imaging (MRI), an epidural mass compressing the spinal cord at the level of the thoracic spine segment 4 (T4) was found. The mass histology confirmed the diagnosis of myeloid sarcoma.

Myeloid Sarcoma: A Primer for Radiologists

ABSTRACT

Myeloid sarcoma (MS) is a rare extramedullary neoplasm that can present in association with acute myeloid leukemia, most commonly in children younger than 15 years. This unique extramedullary malignancy may involve a variety of different organ systems and can present following, preceding, simultaneous with, or in insolation to acute myeloid leukemia. Common areas of extramedullary involvement include soft tissues, bones, lymph nodes, and the peritoneum. Imaging plays a critical role in the diagnosis and management of MS, with commonly used modalities including positron emission tomography-computed tomography, magnetic resonance imaging, computerized tomography, and ultrasound. The purpose of this review article is to provide radiologists with a comprehensive guide summarizing the relevant imaging and clinical features of MS, with emphasis on the role of imaging in the diagnosis, treatment, and follow-up of patients with MS. The relevant pathophysiology, epidemiology, clinical presentations, and differential diagnosis of MS will be reviewed. The relevance of different imaging modalities in diagnosis, monitoring of treatment response, and assessment of treatment-related complications will also be outlined. Through summarizing these topics, this review article aims to provide radiologists with a guide for understanding the existing knowledge of MS in the literature and the current role of imaging in the management of this unique malignancy.

Presentation of Chloromas in B-Mode Ultrasound and Contrast-Enhanced Ultrasound

Chloromas, also referred to as myeloid sarcomas, describe rare extramedullary tumor aggregates of malignant myeloid progenitor cells. The aim of this study was investigate the diagnostic features and characteristics of chloromas using contrast-enhanced ultrasound (CEUS). Between July 2007 and April 2021, 15 patients with 20 myeloid neoplasms and suspected chloroma manifestations were examined using B-mode US (B-US) and CEUS. Clinical data and B-US (echogenicity, border, size) and CEUS (hyper-, iso-, hypo- or complex enhancement) characteristics were retrospectively analyzed. Absolute and relative frequencies were determined. In B-US, the chloromas were most frequently hypo-echoic (n = 15, 75%). In addition, a hyperechoic (n = 2, 10%) or echocomplex (n = 3, 15%) presentation was observed. On CEUS, 7 chloromas (35%) had an arterial hyperenhancement, 8 (40%) an iso-enhancement and 3 (15%) a complex enhancement. Two chloromas (10%) did not exhibit any enhancement. We describe for the first time CEUS and B-US patterns of chloromas. They are typically hypo-echoic on B-US and have a strong iso- or hyperenhancement on CEUS, which may help in the differential diagnosis of some unclear masses (e.g., hematoma, abscess) in patients with myeloid neoplasias. Nevertheless, histology is necessary for a reliable diagnosis.

Bilateral Orbital Myeloid Sarcomas: A Unique Presentation of Acute Myeloid Leukemia

Myeloid sarcomas (MS) are solid manifestations of acute myeloid leukemia (AML) and are commonly present in children. These tumors can arise in many tissues including bone, soft tissue, or skin, and are commonly seen in the orbit. As practically all MS will, if left untreated, eventually present as AML, early diagnosis and initiation of treatment are imperative. We highlighted a case of bilateral orbital MS in a pediatric patient that presented concurrently with AML and the steps taken to diagnose and initiate treatment. Our case highlights the potentially occult presentation of AML as well as myeloid sarcoma and, therefore, the importance of swift workup and diagnosis. Epidemiology, radiographic features, diagnosis, and treatment for myeloid sarcoma and AML were discussed.

Hyperostosis in orbital rhabdomyosarcoma

Rhabdomyosarcoma is the most common soft-tissue sarcoma in paediatric patients and may arise as a primary orbital neoplasm. Imaging studies show a unilateral solitary orbital lesion. With larger tumours, erosion of the adjacent orbital walls is a common accompanying bony change. We present an unusual case of rhabdomyosarcoma in a preschool girl with proptosis and temporal bossing. Imaging studies showed a homogeneous, well-delineated, extraconal mass of the right orbit with hyperostosis of the adjacent sphenoid bone. After excision of the mass and debulking of the sphenoid bone, histopathology showed embryonal rhabdomyosarcoma with no malignant infiltration of the adjacent bone. This is the first reported case of hyperostosis associated with rhabdomyosarcoma. Periosteal reaction is the proposed underlying mechanism.

Myeloid sarcoma of the skull base: A case report and systematic literature review

Background:

Myeloid sarcoma (MS), or chloroma, is a rare extramedullary malignant tumor that consists of undifferentiated granulocytic cells, and it is most commonly associated with acute myeloid leukemia (AML). Intracranial MS accounts for 0.4% of MS cases, and involvement of the skull base and visual dysfunction is rarely reported. However, the optimal treatment and response to treatment of skull base MS in the presence of visual symptoms is unknown.

Case Description:

A 30-year-old male with a history of AML presented with rapidly progressive vision loss and a sellar and parasellar mass with bilateral cavernous sinus and optic nerve encasement. The patient underwent endoscopic endonasal transsphenoidal biopsy revealing intracranial MS. He was treated postoperatively with high-dose intravenous and intrathecal cytarabine and had complete restoration of his vision by postoperative day 11. A systematic review of the literature identified six cases of skull base MS, five of whom presenting with visual symptoms. All patients underwent systemic chemotherapy with cytarabine and/or cyclophosphamide, with infrequent use of intrathecal chemotherapy or radiation. Those with reported visual outcomes were diagnosed 4 months or longer after symptom onset and demonstrated no visual improvement with treatment.

Conclusion:

Skull base MS is a rare disease entity with a high prevalence of visual dysfunction. Our patient’s complete disappearance of intracranial disease and resolution of visual symptoms with systemic and intrathecal chemotherapy highlight the importance of timely diagnosis and appropriate treatment without a need for direct surgical decompression.

Unusual presentations of central nervous system myeloid sarcoma

Myeloid sarcoma (MS), also termed 'chloroma' or 'granulocytic sarcoma', is a tumour mass consisting of myeloid blasts occurring at an anatomical site other than the bone marrow. MS occurs in up to 8% of patients with acute myeloid leukaemia. While MS typically involves the skin or lymph nodes, almost any tissue can be affected, and symptoms largely depend on the organ involved and subsequent mass effect. We present a case series of patients that presented to a tertiary hospital with MS affecting the central nervous system over a 4-month period. These three cases demonstrate the vast spectrum of clinical presentations of MS and, furthermore, show rare examples of intramedullary spinal cord involvement and disseminated intraparenchymal brain disease.

Extramedullary Infiltration in Pediatric Acute Myeloid Leukemia on Surveillance Magnetic Resonance Imaging and its Relationship With Established Risk Factors

PURPOSE

Extramedullary infiltration (EMI) is a rare condition defined by the accumulation of myeloid tumor cells beyond the bone marrow. The clinical significance is still controversial. This study was aimed to evaluate the incidence, characteristics, and prognostic significance of EMI on complete magnetic resonance imaging (MRI) investigation in newly diagnosed pediatric acute myeloid leukemia (AML) patients who are asymptomatic without clinical evidence to suspect EMI.

MATERIALS AND METHODS

Retrospective clinical and radiologic review of 121 patients with MRI examination at the time of initial diagnosis of AML without any clinical evidence suggestive of EMI was performed. Patients were divided into 2 groups according to the presence or absence of EMI, and the relationship between EMI and established risk factors was analyzed. Initial white blood cell count, the occurrence of an event (including relapse, death, and primary refractory disease), survival status, and detailed information on cytogenetic/molecular status was performed by a thorough review of electronic medical records system. All patients underwent full imaging evaluation with the contrast-enhanced whole body and some regional MRI at the time of initial diagnosis.

RESULTS

The median age at diagnosis was 10.77 years (range, 0.37 to 18.83 y). Based on the risk stratification system of AML, 36, 45, and 40 patients are classified as low-risk, intermediate-risk, and high-risk groups, respectively. MRI at the time of the initial diagnosis of AML revealed 35 of 121 patients (28.9%) with EMI. The most common site of EMI was a skull, followed by the lower extremity bone and meninges of the brain. The median age at diagnosis was significantly younger in patients with EMI (7.87 vs. 11.08 y, P=0.0212). Low incidence of FLT3/ITD mutation, low incidence of AML-ETO gene rearrangement, and the larger extent and more severe degree of bone marrow involvement was related with EMI. However, there was no significant prognostic difference in event-free survival and overall survival regardless of the presence of EMI in the overall patient population and each risk group. The location of EMI occurrence was also not related to prognosis.

CONCLUSIONS

Even if EMI symptoms are not evident, surveillance MRI scans at the initial diagnosis of pediatric AML patients are very helpful in detecting a significant number of EMIs. Younger age, some molecular features, and more severe bone marrow involvement of AML patients were related with EMI. However, there was no significant prognostic difference between patients with or without EMI regardless of risk group. Further prospective investigation is necessary to validate the prognostic effect of EMI in a larger group of patients with different risk groups.

Spinal Chloroma – Herald of blast crisis in a patient with chronic myeloid leukaemia: A case report

Myeloid sarcoma or chloroma is a localised tumour characterised by extramedullary proliferation of precursor myeloid cells. Commonly occurring in association with acute myeloid leukaemia, chloroma can occasionally be seen in myeloproliferative disorders with subsequent blastic transformation. Imaging plays an important role in the diagnosis and evaluation of this entity. A case of chloroma involving the dorso-lumbar vertebral region is presented in a patient with chronic myeloid leukaemia with subsequent blastic transformation.

Analysis of PET parameters predicting response to radiotherapy for myeloid sarcoma

Purpose

Positron-emission tomography (PET)-CT has recently been used for diagnostic imaging and radiotherapy for myeloid sarcoma, but there is little research on predicting the response of radiotherapy. The aim of this study was to analyze the association between PET-CT variables and the response to radiotherapy in patients with myeloid sarcoma.

Materials and methods

This study was conducted in myeloid sarcoma patients who received radiotherapy and PET-CT before and after radiotherapy. The response to radiotherapy was evaluated based on the European Organization for Research and Treatment of Cancer PET response criteria, and binary regression analysis was performed to assess the factors predicting reductions in the maximum standardized uptake value (SUVmax).

Results

Twenty-seven sites in 12 patients were included in the study. Complete metabolic responses were seen in 24 patients after radiotherapy, a partial metabolic response in one, and progressive metabolic disease in two patients. The prescribed dose of more than 3000 cGy₁₀ was significantly greater in the treatment control group (P = 0.024). In binary logistic regression analysis predicting reductions in the SUVmax of more than 70% after radiotherapy, the pretreatment SUVmax (≥ 7.5) and further chemotherapy after radiotherapy showed significant differences in univariate and multivariate analyses.

Conclusion

Good metabolic responses (complete or partial) to radiotherapy were achieved in 92.6% of the myeloid sarcoma patients. Radiation doses < 3000 cGy₁₀ and increased SUVmax were related to treatment failure and high SUVmax before radiotherapy was a factor influencing SUVmax reduction. Further large-scale studies are needed.

Tuberculosis in Posttransplant Recipients: Challenges in Fluorodeoxyglucose Positron Emission Tomography/Computed Tomography Reporting in Countries with a High Prevalence of Tuberculosis

Tuberculosis (TB) is a common bacterial infection in developing countries. Solid-organ and hematopoietic stem cell transplant recipients are more prone to this infection. Reactivation from previously acquired infection is the most common mode. It has to be ruled out in cases of pyrexia of unknown origin (PUO) before ruling out the other possibilities. We present two cases of incidentally detected TB in the posttransplant patients referred for the evaluation of PUO.

Radiation Therapy for Chemotherapy Refractory Gingival Myeloid Sarcoma

Gingival myeloid sarcoma (MS) refractory to induction chemotherapy is a rare clinical entity and can be treated with palliative radiation therapy (RT). However, there are few previously published reports of RT approaches for the treatment of gingival MS. We present a single institution retrospective observational study of adult patients treated with palliative RT for chemotherapy refractory gingival MS. A total of six patients diagnosed with gingival MS in the setting of relapsed or refractory acute myeloid leukemia treated with palliative RT were identified, with a median age of 66 (range 52–77). Patients were treated with radiation doses ranging from 5 to 20 Gy in 2–10 fractions. Two patients had adequate follow-up time to assess treatment response. One patient who was simulated with PET/CT experienced a local complete response, while the other patient required retreatment 2 months after initial treatment and experienced an eventual local partial response. Three patients experienced radiation mucositis, with one patient experiencing grade 5 toxicity attributed to concomitant treatment with the radiosensitizer hydroxyurea. We believe that this study can provide a practical reference point for other clinicians given the rarity of gingival MS requiring palliative radiation therapy as a clinical entity.

Brachial plexus chloroma as a presenting feature of relapse in a child with KMT2A-rearranged acute lymphoblastic leukemia, a case report

Approximately 30–40% of relapses in pediatric acute lymphoblastic leukemia (ALL) are extra-medullary. KMT2A gene rearrangements are common in patients with infantile ALL. Chloromas are rare tumors composed of collections of acute leukemic cells that typically involve the bone or skin. Exceptionally uncommon, chloromas invade the peripheral nervous system, a phenomenon termed “neuroleukemiosis.” We describe A 6-year-old girl with a history of pre-B ALL with CNS involvement and KMT2A rearrangement diagnosed initially at 4 months of age. During continuation therapy she developed a scalp mass that was confirmed to be a leukemic relapse. She underwent re-induction chemotherapy followed by blinatumomab with subsequent remission and proceeded to allogeneic hematopoietic cell transplant (HCT). Three years following HCT, she presented with brachial plexus palsy and was found to have a lymphoblastic chloroma invading the brachial plexus. Review of existing literature shows relapse in pediatric ALL patients presenting as brachial plexus chloroma has only been documented once before. It has long been suggested that KMT2A gene rearrangements play a role in development of chloromas in patients with AML, however it is still unclear what role KMT2A has in ALL. Here we report a rare case of ALL relapse that presented as a left arm palsy secondary to a leukemic chloroma invading the brachial plexus and aim to explore the potential role of KMT2A in the formation of ALL chloromas.

Clinical and imaging features of myeloid sarcoma: a German multicenter study

Background

Myeloid sarcoma (MS), also known as chloroma, is an extramedullary manifestation of malignant primitive myeloid cells. Previously, only small studies investigated clinical and imaging features of MS. The purpose of this study was to elucidate clinical and imaging features of MS based upon a multicenter patient sample.

Methods

Patient records of radiological databases of 4 German university hospitals were retrospectively screened for MS in the time period 01/2001 and 06/2019. Overall, 151 cases/76 females (50.3%) with a mean age of 55.5 ± 15.1 years and 183 histopathological confirmation or clinically suspicious lesions of MS were included into this study. The underlying hematological disease, localizations, and clinical symptoms as well as imaging features on CT and MRI were investigated.

Results

In 15 patients (9.9% of all 151 cases) the manifestation of MS preceded the systemic hematological disease. In 43 cases (28.4%), first presentation of MS occurred simultaneously with the initial diagnosis of leukemia, and 92 (60.9%) patients presented MS after the initial diagnosis. In 37 patients (24.5%), the diagnosis was made incidentally by imaging. Clinically, cutaneous lesions were detected in 35 of 151 cases (23.2%). Other leading symptoms were pain (n = 28/151, 18.5%), neurological deficit (n = 27/151, 17.9%), swelling (n = 14/151, 9.3%) and dysfunction of the affected organ (n = 10/151, 6.0%). Most commonly, skin was affected (n = 30/151, 16.6%), followed by bone (n = 29/151, 16.0%) and lymphatic tissue (n = 21/151, 11.4%). Other localizations were rare. On CT, most lesions were homogenous. On T2-weighted imaging, most of the lesions were hyperintense. On T1-weighted images, MS was hypointense in n = 22/54 (40.7%) and isointense in n = 30/54 (55.6%). A diffusion restriction was identified in most cases with a mean ADC value of 0.76 ± 0.19 × 10^− 3 mm²/s.

Conclusions

The present study shows clinical and imaging features of MS based upon a large patient sample in a multicenter design. MS occurs in most cases meta-chronous to the hematological disease and most commonly affects the cutis. One fourth of cases were identified incidentally on imaging, which needs awareness of the radiologists for possible diagnosis of MS.

Subdural haematoma mimics

A subdural haematoma (SDH) is a frequently encountered pathology seen on an emergency room computed tomography (CT) head scan. An extra-axial crescentic density along the convexity of the brain or within the interhemispheric fissure is generally thought to represent a SDH; however, SDH mimics are known to occur in nature, and can be broadly classified under the subcategories of normal anatomy, artefacts, tumour, inflammation, infection, ischaemia, trauma, and iatrogenic. Understanding the typical characteristics of a SDH, knowledge of normal anatomy, close inspection of the morphology of the subdural process, changes to the adjacent structures, and rigorous attention to clinical details may reveal subtle clues that distinguish a true SDH from a mimic. This is crucial in appropriately directing clinical management. This review amalgamates most of the rare subdural processes that have been reported to mimic SDH, and discusses the imaging and clinical features that help to differentiate between them. This topic is highly valuable for radiology trainees, general radiologists, and emergency room physicians, and may serve as a refresher for the practising neuroradiologist.

Radiological and clinical patterns of myeloid sarcoma

Background Myeloid sarcoma (MS), also known as granulocytic sarcoma or chloroma, is a solid tumor of extramedullary localization composed of malignant primitive myeloid cells. The purpose of the study was to identify clinical and imaging features in a large patient sample. Patients and methods Overall, 71 cases (34 females (47.9%) and 37 males (52.1%) with a median age of 56 (± 16 years) of histopathologically confirmed myeloid sarcoma were included into this study. The underlying hematological disease, occurrence, localizations and clinical symptoms as well as imaging features on computed tomography and magnetic resonance imaging were investigated. Results In 4 cases (5.63%) the manifestation of MS preceded the systemic hematological disease by a mean value of 3.8 ± 2.1 months. In 13 cases, first presentation of MS occurred simultaneously with the initial diagnosis of leukemia, and 51 patients presented MS after the initial diagnosis of the underlying malignancy with a mean latency of 39.8 ± 44.9 SD months. The visceral soft tissue was affected in 26 cases, followed by the cutis/subcutis was affected in 21 cases. Further localizations were bones (n = 13), central nervous system (n = 9), lymph nodes (n = 4) and visceral organs (n = 9). Conclusions MS is a rare complication of several hematological malignancies, predominantly of acute myeloid leukemia, which can affect any part of the body. In most cases it occurs after the diagnosis of the underlying malignancy, and affects frequently the cutis and subcutis.

Craniofacial Manifestations of Systemic Disorders: CT and MR Imaging Findings and Imaging Approach

Many systemic diseases or conditions can affect the maxillofacial bones; however, they are often overlooked or incidentally found at routine brain or head and neck imaging performed for other reasons. Early identification of some conditions may significantly affect patient care and alter outcomes. Early recognition of nonneoplastic hematologic disorders, such as thalassemia and sickle cell disease, may help initiate earlier treatment and prevent serious complications. The management of neoplastic diseases such as lymphoma, leukemia, or Langerhans cell histiocytosis may be different if diagnosed early, and metastases to the maxillofacial bones may be the first manifestation of an otherwise occult neoplasm. Endocrinologic and metabolic disorders also may manifest with maxillofacial conditions. Earlier recognition of osteoporosis may alter treatment and prevent complications such as insufficiency fractures, and identification of acromegaly may lead to surgical treatment if there is an underlying growth hormone-producing adenoma. Bone dysplasias sometimes are associated with skull base foraminal narrowing and subsequent involvement of the cranial nerves. Inflammatory processes such as rheumatoid arthritis and sarcoidosis may affect the maxillofacial bones, skull base, and temporomandibular joints. Radiologists should be familiar with the maxillofacial computed tomographic and magnetic resonance imaging findings of common systemic disorders because these may be the first manifestations of an otherwise unrevealed systemic process with potential for serious complications. Online supplemental material is available for this article. ^©RSNA, 2018.