Granulocytic Sarcoma Mimicking HSV Encephalitis

Treatment Outcomes of Intracranial Myeloid Sarcomas: A Meta-Analysis

OBJECTIVE

Intracranial myeloid sarcomas (IMS) are rare central nervous system manifestations of malignant hematopoietic neoplasms of myeloid origin such as acute myeloid leukemia and chronic myeloid leukemia. Reported cases in the literature are limited to primarily case reports. We present a systematic review of this rare central nervous system tumor, characterizing the clinical presentation, tumor location, histopathology, and available treatment modalities. We correlate these variables with mortality, recurrence, and complications to suggest optimal management strategies for IMS.

METHODS

A systematic literature search was performed across Ovid MEDLINE, Scopus, and Embase using 14 search terms in accordance to Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. This systematic review examines variables such as patient age, tumor location, size, presenting symptoms, treatment modality, extent of resection, and mortality. We performed descriptive analyses to identify bivariate associations between patient characteristics, treatment, and outcomes.

RESULTS

The mean age at diagnosis was 34.8 years, and the most common etiology was acute myeloid leukemia (68.8%). The most common presenting symptoms were headache (45.5%), vision complaints (27.3%), and weakness/motor symptoms (21.2%). IMS were most commonly located in the temporal lobe (10.1%), cerebellum (10.1%), or falcine/parasagittal (10.1%) region. Patients who received radiotherapy (P < 0.001) or chemotherapy (P < 0.001) had lower rates of mortality versus those who did not. Surgical treatment and extent of resection were not significantly associated with mortality (P > 0.05).

CONCLUSION

The use of adjuvant radiotherapy or chemotherapy for IMS significantly reduces mortality, confirming IMS as a cranial manifestation of a systemic disease. Although surgical treatment is indicated for histopathologic diagnosis and to relieve mass effect, the extent of resection does not predict overall survival.

Lateralized Periodic Discharges: A Literature Review

The purpose of this article is to provide a comprehensive review of the literature about a particular EEG pattern, lateralized periodic discharges (LPDs), or periodic lateralized epileptiform discharges (PLEDs). The review will discuss the history and terminology of LPDs and provide a detailed summary of the etiologies, pathophysiology, clinical symptoms, and imaging studies related to LPDs. Current controversies about the association of LPDs with seizures and their management will be reviewed. Finally, some unanswered questions and suggestions for future research on LPDs will be discussed.

Is acute myeloid leukemia a liquid tumor?

Extramedullary manifestations of acute myeloid leukemia (AML) were described as early as the 19th century. However, the incidence, clinical significance and pathobiology of extramedullary AML remain ill defined. We reviewed case reports, retrospective case series, pilot studies and imaging studies of extramedullary leukemia (EML) to determine its frequency, characteristics, clinical presentation and significance. EML precedes or accompanies development of AML and occurs during or following treatment, even during remission. Although imaging studies are rarely conducted and the true incidence of EML has yet to be verified, authors have reported several estimates based on retrospective and autopsy studies. The incidence of EML in patients with AML of all ages is estimated to be about 9% and EML in children with AML was detected in 40% of patients at diagnosis. The combination of positron emission tomography and computed tomography were the most sensitive and reliable techniques of detecting and monitoring EML. Based on our literature review, the frequency of EML is likely underreported. The well-documented nature of EML in patients with AML suggests that AML can manifest as a solid tumor. The extent to which EML accompanies AML and whether EML is derived from bone marrow are unknown. Furthermore, questions remain regarding the role of the microenvironment, which may or may not facilitate the survival and proliferation of EML, and the implications of these interactions with regard to minimal residual disease, tumor cell quiescence and relapse. Therefore, prospective studies of detection and characterization of EML in patients with AML are warranted.