Janus kinase 2 V617F mutation is detectable in spleen of patients with chronic myeloproliferative diseases suggesting a malignant nature of splenic extramedullary hematopoiesis

Extramedullary hematopoiesis occurs in patients with a variety of hematologic diseases, and the spleen is a common site. Extramedullary hematopoiesis is very common in chronic myeloproliferative diseases and myeloproliferative/myelodysplastic diseases. The pathogenesis of extramedullary hematopoiesis is unknown. Using JAK2 V617F mutation as a molecular marker, we assessed paired spleen and bone marrow samples of 15 patients with various types of chronic myeloproliferative diseases and myeloproliferative/myelodysplastic diseases. The diagnosis was chronic idiopathic myelofibrosis (n=8), polycythemia vera (n=3), and chronic myelomonocytic leukemia (n=4). DNA was extracted from fixed, paraffin-embedded tissue and assessed for JAK2 V617F by real-time polymerase chain reaction assay followed by melting curve analysis. Concordant JAK2 mutation was detected in the paired samples in 7 patients. A discordant result with JAK2 V617F found in the spleen but not bone marrow was noted in 1 patient. These results indicate that extramedullary hematopoiesis in patients with chronic myeloproliferative diseases and myeloproliferative/myelodysplastic diseases is a clonal process and lend support to the theory that the cells of extramedullary hematopoiesis are carried from the bone marrow.     

Recruited peripheral blood monocytes participate in the liver extramedullary hematopoietic milieu

The hematopoietic microenvironment has been investigated and well defined in the bone marrow. However, there is a lack of studies on the extramedullary hematopoietic milieu such as in the liver, to which hematopoietic stem cells migrate and there commence hematopoiesis under pathological conditions such as bone marrow failure. We induced extramedullary hematopoiesis by phenylhydrazine in the adult mouse liver and investigated the immunohistochemical, ultrastructural, and molecular changes within this organ. Using an intravital lectin injection technique, we found numerous monocytes attached to the central vein prior to hematopoietic foci formation. These cells were later incorporated into the hematopoietic foci. An increase in the mRNA expressions of the monocyte attracting chemokine CCL-2 (MCP-1) was noted in the central vein region as well as in cells within the hematopoietic foci. Together with local liver components, we regard these monocytes as components of the extramedullary hematopoietic milieu. We conclude that the recruitment of extra-hepatic monocytes is an important event during extramedullary hematopoiesis in the liver and that these monocytes participate in the liver hematopoietic microenvironment.     

Fine-needle aspiration biopsy diagnosis of intrathoracic extramedullary hematopoiesis presenting as a posterior mediastinal tumor in a patient with sickle-cell disease: Case report

Extramedullary hematopoiesis (EMH) is a rare cause of an intrathoracic mass. Fine-needle aspiration biopsy (FNAB) has been only occasionally documented as a useful tool in diagnosing EMH tumor. We report a case of posterior mediastinal extramedullary hematopoietic mass in an 80-yr-old man with sickle-cell anemia. The mass was revealed incidentally on chest X-ray. The definitive diagnosis of this mass lesion was achieved by FNAB. The cytologic smears showed hematopoietic elements with erythroid hyperplasia. A correct cytologic diagnosis can thus help to avoid unnecessary surgical intervention, particularly in an asymptomatic patient.     

Morphologic and immunohistochemical evaluation of splenic hematopoietic proliferations in neoplastic and benign disorders.

Spleen is a common site of extramedullary hematopoiesis. Extramedullary hematopoiesis seen in non-neoplastic conditions can occasionally be extensive and raise concerns for a myeloid neoplasm. We compared the morphologic and immunohistochemical features of splenic hematopoietic proliferations seen in neoplastic myeloid disorders (eg chronic myeloproliferative disorders, myelodysplastic/myeloproliferative disorders and acute myeloid leukemias) to extramedullary hematopoiesis seen in a variety of reactive conditions. In all, 80 spleen specimens were reviewed. The presence of each marrow-derived lineage, dysplasia and immunohistochemical results were evaluated (CD34, CD117, myeloperoxidase, CD68, p53, TdT, CD42b and hemoglobin). Neoplastic hematopoietic proliferations in chronic myeloproliferative disorders are characterized by trilineage hematopoiesis with significant dysplasia in all cell lineages. Acute myeloid leukemia showed an increase in immature forms, which were highlighted by immunohistochemistry. Reactive extramedullary hematopoiesis showed variability in histologic features. Post-bone marrow transplant and thrombotic thrombocytopenic purpura/hemolytic-uremic syndrome spleens showed extramedullary hematopoiesis with some morphologic features of immaturity, which could simulate chronic myeloproliferative disorder. However, they lacked characteristic immunohistochemical features of neoplastic myeloid disorders such as positivity for CD34 or CD117.     

Extramedullary hematopoiesis presented as solitary renal mass: a case report with review of literature

In this article, we described a case of extramedullary hematopoiesis (EMH) in a 12-year-old boy with the clinical and hematological features of hemolytic anemia of unknown cause. The patient presented with a solitary well circumscribed mass in right kidney. Ultrasound guided fine-needle aspiration cytology showed myelocytes, metamyelocytes, megakaryocytes, and immature erythroid cells. A cytological diagnosis of EMH was made.     

Extramedullary hematopoiesis in the liver in sudden infant death syndrome

Liver extramedullary hematopoiesis was examined in 54 victims of sudden infant death syndrome and in 21 infants who died of other causes in an attempt to confirm Naeye's findings of increased extramedullary hematopoiesis in cases of sudden infant death syndrome. Our data showed greater extramedullary hematopoiesis in victims of sudden infant death syndrome (F = 23.52), supporting Naeye's hypothesis that victims of sudden infant death syndrome have suffered a subtle, chronic hypoxemic condition before death.     

Tumor-simulating retrorectal heterotopia of bone marrow.

A retrorectal tumor-simulating mass of extramedullary hematopoiesis was discovered during work-up for uterine bleeding in a 40-year-old woman. It was excised in toto. The only hematologic abnormality at the time was iron deficiency, which was corrected. Six years later the patient is free of recurrence or any hematologic abnormality. It is suggested that this case represents heterotopic marrow arising either as a remnant of embryonic hematopoiesis or from activated primitive cells retaining the embryonic potentiality of hematopoiesis. The difficult diagnostic problems, pathogenesis and treatment are discussed, and the importance of recognizing the trilineage of hematopoiesis using Wright's-stained imprints of the mass is emphasized.     

37-year-old woman with multiple intracranial masses

Extramedullary hematopoiesis (EMH), defined as the presence of hematopoiesis outside bone marrow and peripheral blood, occurs asa compensatory phenomenon in several hematologic disorders and bone marrow dysfunction. EMH predominantly affects reticuloendothelial system including the spleen, liver and lymph nodes. Here,we report a rare case of multiple intracranial meningeal EMH. A37-year-old woman was anemic with gradually worsening vision for 8 months. Multiple extra-axial masses were found on imaging and the patient underwent the biopsy for the left frontotemporal lesion.Final diagnosis was multiple intracranial meningeal EMH. Treatment of fractionated external beam radiotherapy resulted in marked symptomatic improvement. This case indicates that although the diagnosis of meningeal EMH is difficult, there is a need to consider EMHin the differential diagnosis of anemic patients with tumor-like mass lesions in extramedullary sites.     

Alveolar airspace and pulmonary artery involvement by extramedullary hematopoiesis: a unique manifestation of myelofibrosis

Pulmonary extramedullary hematopoiesis is a rare manifestation of myelofibrosis. We encountered a unique case of pulmonary extramedullary hematopoiesis occurring in a 59-year-old white man, where in addition to the typical foci of interstitial hematopoietic cells, a surgical lung biopsy showed airspace and arterial wall involvement. Airspace foci were associated with acute and organizing alveolar hemorrhage, while within arteries the hematopoietic elements had a striking predilection for the vascular intima. The hematopoietic foci included erythroid precursors, myeloid precursors, and megakaryocytes, which were immunoreactive with hemoglobin, myeloperoxidase, and CD61, respectively. Whether extramedullary hematopoiesis represents in situ embryonic stem cell differentiation or a compensatory seeding of hematopoietic cells from the bone marrow remains to be elucidated. However, familiarity with these findings in the lung could be helpful in uncovering occult hematological disorders accompanied by extramedullary hematopoiesis. Extramedullary hematopoiesis should also be considered as a cause of pulmonary hemorrhage, especially in the setting of myelofibrosis.     

An unusual form of chronic myeloproliferative disorder. Aleukemic basophilic leukemia

A 52-year-old Japanese man manifested various clinical signs and symptoms such as vomiting, high fever, dyspnea, cough, sweating, palpitation, eosinophilic leukocytosis and hepatosplenomegaly. These histamine-related clinical manifestations showed a dramatic response to steroid therapy. After 10 months of hospitalization, he suddenly succumbed to candidal septicemia at the end of the third cycle of steroid therapy. Autopsy revealed neoplastic proliferation of immature basophils in various internal organs without involvement of the skin. The neoplastic cells, positive immunohistochemically for leukocyte common antigen, possessed lobulated nuclei and weakly metachromatic cytoplasmic granules, predominantly of the basophil type, which exhibited weak naphthol ASD-chloroacetate esterase activity. Mast cell-type granules were also observed ultrastructurally. The neoplastic infiltration was associated with fibrosis in the liver, spleen and bone marrow and with extramedullary hematopoiesis in the liver, spleen, lymph nodes and perihypophyseal tissue. The bone marrow showed uneven and multifocal involvement. Despite the lack of leukemic manifestations and the results of chromosomal analysis, the most suitable diagnosis was aleukemic basophilic leukemia within the category of chronic myeloproliferative disorder. Kinship of this neoplasia to systemic mastocytosis is discussed.     

Hepatic sinusoidal fibrosis in agnogenic myeloid metaplasia

Autopsy studies in two patients who had agnogenic myeloid metaplasia of long duration revealed significant extramedullary hematopoiesis in the liver associated with significant hepatic perisinusoidal/sinusoidal fibrosis. Fibrosis was nonzonal and irregularly distributed throughout the livers. Early changes were found in areas with normal parenchymal architecture and showed significant thickening of collagen fibers surrounding the liver cell plates. In areas with extensive fibrosis, coarse collagen fibers filled the sinusoidal space and resulted in the loss of hepatocytes, but nodular regeneration was absent. Hepatic perisinusoidal/sinusoidal fibrosis in livers with extensive extramedullary hematopoiesis may be more common than previously recognized.     

T-cell-rich B-cell lymphoma presenting in the spleen: a clinicopathologic analysis of 3 cases

We review the clinical, pathologic, and molecular genetic features of 3 splenic T-cell-rich B-cell lymphomas and discuss their differential diagnosis. All patients presented with symptomatic splenomegaly and underwent diagnostic/therapeutic splenectomy. Microscopically, the spleen in all cases showed a micronodular proliferation of lymphoid cells. A proportion of the nodules demonstrated central hyalinization or sclerosis. There was also an exuberant extramedullary hematopoiesis. On immunohistochemical stain, the nodules consisted predominantly of small T cells with scattered large atypical B cells. The clonal nature of the atypical B cells was confirmed by polymerase chain reaction assays for immunoglobulin heavy-chain gene rearrangement. In the H&E sections, the differential diagnoses included Hodgkin's lymphoma, follicular lymphoma, peripheral T-cell lymphoma, and nonneoplastic granulomatous process. The presence of exuberant extramedullary hematopoiesis also raised the possibility of a chronic myeloproliferative disorder. The combined morphologic, immunohistochemical, and molecular genetic data are essential for a correct diagnosis of splenic T-cell-rich B-cell lymphoma.     

Bronchial extramedullary hematopoiesis preceding chronic myelogenous leukemia

Extramedullary hematopoiesis of the bronchus is rare. The case of a 72-year-old man in whom the right lower lobe bronchus was obstructed by extramedullary hematopoiesis is presented. Ten months after the initial presentation, Philadelphia chromosome-negative chronic myelogenous leukemia was diagnosed. Such findings have not been reported previously. The various anatomic locations of extramedullary hematopoiesis are reviewed, with an emphasis on intrathoracic and pulmonary presentations. The clinical and pathologic features and the differential diagnosis in the present case are discussed.     

An Unusual Form of Chronic Myeloproliferative Disorder Aleukemic Basophilic Leukemia

A 52-year-old Japanese man manifested various clinical signs and symptoms such as vomiting, high fever, dyspnea, cough, sweating, palpitation, eosinophilic leukocytosis and hepatosplenomegaly. These histamine related clinical manifestations showed a dramatic response to steroid therapy. After 10 months of hospitalization, he suddenly succumbed to candidal septicemia at the end of the third cycle of steroid therapy. Autopsy revealed neoplastic proliferation of immature basophils in various internal organs without involvement of the skin. The neoplastic cells, positive immunohistochemically for leukocyte common antigen, possessed lobulated nuclei and weakly metachromatic cytoplasmic granules, predominantly of the basophil type, which exhibited weak naphthol ASD-chloroacetate esterase activity. Mast cell type granules were also observed ultrastructurally. The neoplastic infiltration was associated with fibrosis in the liver, spleen and bone marrow and with extramedullary hematopoiesis in the liver, spleen, lymph nodes and perihypophyseal tissue. The bone marrow showed uneven and multifocal involvement. Despite the lack of leukemic manifestations and the results of chromosomal analysis, the most suitable diagnosis was aleukemic basophilic leukemia within the category of chronic myeloproliferative disorder. Kinship of this neoplasia to systemic mastocytosis is discussed. Acta Pathol Jpn 41: 73 81, 1991.     

Vascular proliferation as an unusual cause of hemorrhagic diathesis in myelofibrosis.

One year after splenectomy, a patient with myelofibrosis developed spontaneously large hematomas that were not due to coagulation abnormalities or functionally defective platelets. At autopsy, the liver, muscle, and skin showed extramedullary hematopoiesis associated with capillary proliferation and extravasation of blood. These findings indicate that neovascularization can be an additional cause of bleeding in myeloproliferative disorders and might be induced by neoplastic hematopoietic cells.     

Fine-needle aspiration of extranodal and extramedullary hematopoietic malignancies

There is relatively little information concerning the use of fine-needle aspiration (FNA) to diagnose extranodal and extramedullary hematopoietic malignancies. Seventy-one such cases diagnosed by FNA form the basis of this study. Seventy-one cases of FNAs performed between 1988 and 1998 on extranodal and extramedullary hematopoietic malignancies were reviewed in order to evaluate the usefulness of this technique in diagnosing these entities as well as to assess patterns of relapse. There were 45 male and 26 female patients ranging in age from 29-86 years (mean, 68 years). Sixty-six patients had a previous history of a hematopoietic malignancy. Aspirates from 65 of these patients were consistent with the patient's known primary. One aspirate of a paravertebral mass from a multiple myeloma patient showed extramedullary hematopoiesis. The remaining five aspirates were cases of multiple myeloma that first presented as soft tissue masses. The most common malignancies were lymphoma: 52 cases (73%), 48 large cell lymphomas, four mixed small and large cell lymphoma; followed by multiple myeloma: 12 cases (17%); leukemia: four cases (5.4%); Hodgkin disease: two cases (2.8%); and one case of extramedullary hematopoiesis. The aspirate sites were soft tissue: 23 cases (32%); bone: 17 cases (24%); kidney: 14 cases (20%); liver: 11 cases (15%); lung: three cases (4%); adrenal: two cases (3%); and eye: one case. The interval between primary diagnosis and FNA was 1-36 months (mean, 13 months). In conclusion, 98% of the aspirates were neoplastic in patients with a known history of hematopoietic malignancies. The most common site of involvement was soft tissue in 23 (32%) cases. In five patients with multiple myeloma, the FNA diagnosis prompted a work-up to find the primary site of involvement. FNA is a useful technique in assessing extranodal and extramedullary hematopoietic malignancies.     

Nonsyndromatic paucity of intrahepatic bile ducts in congenital syphilis. A case report

The first case of nonsyndromatic paucity of the intrahepatic bile ducts is reported in congenital syphilis. The patient, a 2-week-old female, was born at the 31st week of gestation, weighing 1,910 g. She had a high titer of IgM antibody to Treponema pallidum and sera from both parents also showed a positive reaction in the hemagglutination test for Treponema pallidum. The patient had hepatosplenomegaly and increasing jaundice, and died of respiratory failure on the 70th hospital day. Autopsy examination revealed paucity of the intrahepatic bile ducts, prominent giant cell transformation of hepatocytes, cholestasis and extramedullary hematopoiesis of the liver. The ratio of the number of intrahepatic bile ducts to that of the portal tracts was approximately 0.2:1. There was marked proliferation of atypical bile ductules at the margin of the portal tracts. The exact relation of this paucity to Treponema pallidum remains unknown.     

Stromal-derived factor-1 and its receptor, CXCR4, are constitutively expressed by mouse liver sinusoidal endothelial cells: implications for the regulation of hematopoietic cell migration to the liver during extramedullary hematopoiesis

Stromal-derived factor (SDF)-1 is the main regulating factor for trafficking/homing of hematopoietic stem cells (HSC) to the bone marrow (BM). It is possible that this chemokine may also play a fundamental role in regulating the migration of HSC to several organs during extramedullary hematopoiesis. Because liver sinusoidal endothelial cells (LSEC) constitute an extramedullary niche for HSC, it is possible that these cells represent one of the main cellular sources of SDF-1 at the liver. Here, we show that LSEC express SDF-1 at the mRNA and protein level. Biological assays showed that conditioned medium from LSEC (LSEC-CM) stimulated the migration of BM progenitor lineage-negative (BM/Lin?) cells. This effect was significantly reduced by AMD3100, indicating that the SDF-1/CXCR4 axis is involved in the stimulatory migrating effect induced by LSEC-CM. Early localization of HSC in SDF-1-expressing LSEC microenvironment together with increased levels of this chemokine in hepatic homogenates was found in an experimental model of liver extramedullary hematopoiesis. Flow cytometry studies showed that LSEC express the CXCR4 receptor. Functional assays showed that activation of this receptor by SDF-1 stimulated the migration of LSEC and increased the expression of PECAM-1. Our findings suggest that LSEC through the production of SDF-1 may constitute a fundamental niche for regulation of HSC migration to the liver. To our knowledge, this is the first report showing that LSEC not only express and secrete SDF-1, but also its receptor CXCR4.     

Chronic myelomonocytic leukemia revealed by uncontrollable hematuria

Nephrectomy was performed for uncontrollable unilateral hematuria in an apparently healthy 72-year-old man. The suburothelial connective tissue of the kidney was infiltrated by primitive myeloid cells with associated acute vasculitis and foci of extramedullary hematopoiesis. Subsequently, the patient was shown to have chronic myelomonocytic leukemia. Although renal involvement and vasculitis have been recorded previously in chronic myelomonocytic leukemia, this is the first occasion, to our knowledge, where their concurrence resulted in such a spectacular presentation.     

Cutaneous and pericardial extramedullary hematopoiesis with cardiac tamponade in chronic myeloid leukemia

A 48-year-old woman with Philadelphia chromosome-positive chronic myeloid leukemia developed skin and pericardial extramedullary hematopoiesis. The echocardiogram revealed massive pericardial effusion with signs of tamponade. The cytocentrifuge preparation of pericardial fluid demonstrated all three hematopoietic components. Assays for the granulocyte-macrophage progenitor cells and erythroid progenitors on her pericardial fluid gave rise to colony numbers comparable to those of normal bone marrow cells. The patient was successfully treated with pericardiocentesis followed by short-term indwelling catheter drainage and administration of hydroxy-urea. There was no reaccumulation of fluid at ten months.