Intracranial hematopoiesis in a patient with aids-related central nervous system lymphoma and severe pancytopenia

Report of a Rare Case of Intracranial Extramedullary Hematopoiesis Mimicking a Brain Tumor

Failure of the bone marrow to maintain adequate blood cell production to match blood metabolic demand incites the production of cell lines outside the bone marrow, which is known as extramedullary hematopoiesis. Herein, we are reporting an 80-year-old male patient who presented with two weeks of worsening headaches and behavioral changes. Labs showed thrombocytosis and imaging showed a large right-sided hemorrhagic brain mass. No evidence of malignancy was seen elsewhere. Brain mass biopsy showed intracranial extramedullary hematopoiesis (IEMH) and bone marrow biopsy confirmed the diagnosis of essential thrombocythemia (ET)/myelofibrosis. This case adds to a few reported cases of IEMH, and to the best of our knowledge, this is the first reported case of IEMH in association with ET. It helps remind clinicians to keep IEMH in the differential diagnosis of those presenting with signs and symptoms of elevated intracranial pressure (ICP) and a newly found brain mass on the background of previously diagnosed or suspected myeloproliferative neoplasms.

The Quantification and Significance of Extramedullary Hematopoiesis Seen on Liver Biopsy Specimens

OBJECTIVES

Extramedullary hematopoiesis (EMH) may occur in the liver and is often considered pathologic in adults. Many hematologic and nonhematologic disorders are associated with the development of EMH. However, it is unclear whether the presence of EMH is always pathologic. At present, no formal grading system for EMH in the liver exists.

METHODS

We reviewed 42 liver biopsy specimens with EMH and developed a novel grading system to quantify the degree of EMH from 1 to 3 based on the number of EMH foci in 10 high-power fields.

RESULTS

Most patients had nonhematologic conditions (n = 25). Seventeen patients had a hematologic condition, most frequently a myeloproliferative neoplasm (n = 9). Patients with an underlying hematologic condition had a significantly higher EMH grade compared with those without a hematologic condition (P < .0001). All patients with grade 3 EMH had an underlying hematologic diagnosis, and most (86%) patients with grade 1 EMH had a nonhematologic disorder.

CONCLUSIONS

Our data suggest that EMH grading in the liver is feasible and can identify patients who may have an underlying hematologic condition, which can guide further diagnostic workup.

The mechanisms of pathological extramedullary hematopoiesis in diseases

Extramedullary hematopoiesis (EMH) is the expansion and differentiation of hematopoietic stem and progenitor cells outside of the bone marrow. In postnatal life, as a compensatory mechanism for ineffective hematopoiesis of the bone marrow, pathological EMH is triggered by hematopoietic disorders, insufficient hematopoietic compensation, and other pathological stress conditions, such as infection, advanced tumors, anemia, and metabolic stress. Pathological EMH has been reported in many organs, and the sites of pathological EMH may be related to reactivation of the embryonic hematopoietic structure in these organs. As a double-edged sword (blood and immune cell supplementation as well as clinical complications), pathological EMH has been widely studied in recent years. In particular, pathological EMH induced by late-stage tumors contributes to tumor immunosuppression. Thus, a deeper understanding of the mechanism of pathological EMH may be conducive to the development of therapies against the pathological processes that induce EMH. This article reviews the recent progress of research on the cellular and molecular mechanisms of pathological EMH in specific diseases.

Paraspinal extramedullary hematopoiesis in hereditary spherocytosis with a concurrent follicular lymphoma: case report and review of the literature

We report an unusual case of a 70-year-old male with history of hereditary spherocytosis (HS) and secondary paraspinal extramedullary hematopoiesis with a concurrent follicular lymphoma. The lesion presented as a thoracic paraspinal mass of 9 cm, extending longitudinally between T6 and T9 vertebral bodies. Incisional biopsy revealed that this mass included mature hematopoietic tissue compatible with extramedullary hematopoiesis (EMH). The tissue also presented an extensive and diffuse infiltration by an atypical lymphoid population composed predominantly by small cells. The immunohistochemical study revealed that the atypical lymphoid population had a germinal center phenotype, consistent with the diffuse variant of follicular lymphoma (FL). The simultaneous presence of both EMH and FL in the same lesion made the interpretation and the final diagnosis of this case difficult. The presence of EMH in this clinical context may eclipse the diagnosis of the underlying lymphoproliferative neoplasm. The close association between the tumor cells and extramedullary hematopoietic tissue in the absence of lymphadenopathies or other tissue involvement suggests a relationship of this tumor with the recently described primary FL of the bone marrow.

Intracranial extramedullary haematopoiesis: A case report

Extramedullary haematopoiesis (EMH) is an ectopic production of blood cells to compensate for ineffective haematopoiesis. We report a rare symptomatic presentation of intracranial EMH and discuss its investigation and management. EMH should be considered a differential diagnosis in patients with haemoglobinopathies, haemolytic anaemias and myeloproliferative disorders, who present with symptoms of raised intracranial pressure.

An intracranial extramedullary hematopoiesis in a 34-year-old man with beta thalassemia: a case report

INTRODUCTION

Extramedullary hematopoiesis occurs in approximately 15% of cases of thalassemia. Intracranial deposits of extramedullary hematopoiesis are an extremely rare compensatory process in intermediate and severe thalassemia.

CASE PRESENTATION

We present an unusual case of an intracranial extramedullary hematopoiesis with a choroid plexus origin in a 34-year-old Caucasian man with beta thalassemia intermedia, who presented with the complaints of chronic headache and rapid progressive visual loss.

CONCLUSION

An intracranial extramedullary hematopoiesis, although extremely rare, should be considered as a potential ancillary diagnosis in any thalassemic patient and therefore appropriate studies should be performed to investigate the probable intracranial ectopic marrow before any surgical intervention.