Lymphoid aggregates in bone marrow: study of eventual outcome

Lymphoid aggregates in the bone marrow biopsies of patients with myelodysplastic syndromes - A potential prognostic marker?

Background

Lymphoid aggregates (LA) are occasionally seen in bone marrow biopsies (BMB) of myelodysplastic syndromes (MDS) patients. Our aim was to evaluate their incidence and association with prognosis.

Methods

We compared BMB reports of MDS patients treated at the Tel Aviv Sourasky Medical Center (2011-2018), and controls (2015-2017, normal BMB), and examined the charts of the MDS patients (LA+ and LA-). Categorical, normally and non-normally distributed continuous variables were compared using Fisher's exact, independent t and Mann-Whitney tests respectively. Adjusted [age, gender, lymphocytes, white blood cells (WBC) and diabetes mellitus (DM)] Cox proportional hazard model examined survival at 12 and 24 months.

Results

MDS patients (N=140) were older than controls (N=38; 74.1 vs 69.2 years, p=0.005); 34 MDS (24.3%) and 5 controls (13.2%) had LA+ (P=0.141). CD20/CD3 staining suggested LA polyclonality. MDS/LA+ (vs MDS/LA-) patients were younger, with a trend (not statistically significant) towards poor prognostic parameters: lower Hb, WBC, and platelets, higher LDH, BM cellularity, and IPSS-R score. The incidence of cardiovascular disease was similar, but MDS/LA+ had twice the incidence of DM (38.2% vs 19.0%, p=0.022). Similar trend for cancer (26.5% vs 14.3%, p=0.102). Twelve-month survival: 24/34 (70.6%) MDS/LA+; 88/106 (83.0%) MDS/LA- (p=0.140). This trend, seen in Kaplan-Meier curves, disappeared at 24 months. The hazard ratio for LA was 2.283 (p=0.055) for 12 months.

Conclusion

These preliminary data suggest LA are relatively common (24%) in MDS BMB, and might indicate poor prognosis. This may reflect involvement of the immune system in MDS. Future studies will examine larger groups, to clarify the incidence, significance and the pathophysiology.

Automated enumeration of lymphoid and plasma cells in bone marrow to establish normal reference ranges

Aims

The number of precursor and mature lymphoid cells and plasma cells in normal bone marrow trephine (BMT) biopsies throughout the human lifespan is unknown. Reference ranges have been established from aspirated marrow, but due to haemodilution errors, these do not accurately reflect the native marrow milieu. We aimed to define age-specific, normal reference ranges for lymphoid and plasma cells in BMT biopsy specimens using a combined immunophenotyping and digital enumeration approach.

Methods

Morphologically normal BMT biopsy specimens (n=483) were obtained from patients aged 1 month to 90 years of age. Immunohistochemistry was performed to identify lymphoid progenitors , T-lymphocytes (CD3), B-lymphocytes (CD20) and plasma cells (CD138 and MUM1). Positive cells were counted using digital enumeration software, and the percent positivity for each antigen was determined per case. Mean values were generated for specific age groups, and age-defined reference ranges were determined for each antigen using normalised data.

Results

A mean of 16 609 cells (range: 7210–34 097) were counted per biopsy. Infant marrows showed a predominance of immature lymphoid progenitors and B cells. With increasing age, an increase in mean T cell and plasma cell numbers were observed. The results showed the same trends to flow cytometry references for aspirate material although the absolute values differed.

Conclusions

Combined immunohistochemistry and automated enumeration gives an accurate, reproducible number of antigen-positive cells and has generated normal reference ranges for these cell types in BMT biopsies. The method and ranges we have established have the potential to be applied in routine clinical practice.

Three cases of fever of unknown origin (FUO) with acute multifocal non-bacterial osteitis (NBO) as reactive osteomyelitis

Evaluation for fever of unknown origin (FUO) requires a long list of studies. Recently, the validity of PET scan in FUO evaluation has been approved for screening and qualification. Non-bacterial osteitis (NBO) refers to non-bacterial and non-specific inflammation of bone, which is usually chronic, and involves multiple bony sites. We have experienced 3 cases of FUO associated with increased symmetric multiple fluorodeoxyglucose uptake preferentially at the epiphysis of the femur and tibia on fusion Positron emission tomography/Computed tomography (PET/CT). Patients were young women, who complained of intermittent fever lasting several months, which was associated only with neutropenia and relative lymphocytosis. Bone biopsies revealed increased lymphocytes and histiocyte infiltration of the cortical bone with reactive bone marrow. With no evidence of infection, the fever showed spontaneous remission within 2 weeks of conservative treatment. We report on 3 cases of FUO with self-limited acute NBO as reactive osteomyelitis and suggest that this unique pattern on PET/CT would be helpful for FUO evaluation.

Histopathology of femoral head donations: a retrospective review of 6161 cases

BACKGROUND

Although total hip arthroplasty is one of the most common orthopaedic surgical procedures, it remains unclear whether histopathological examination of the excised femoral head adds to the quality of patient care. We propose that assessment of femoral heads resected during total hip arthroplasty and donated for allograft use may provide a profile of femoral head pathology that benefits total hip arthroplasty patients and bone donors.

METHODS

We retrospectively analyzed the histological findings reported for 6161 femoral heads donated for allograft use between 1993 and 2006. Specimens obtained during total hip arthroplasty and specimens donated at death were reviewed. Follow-up investigations that resulted from abnormal histopathological findings were also reviewed. The Western Australian Cancer Registry was used to determine whether patients with a suspected neoplasm were subsequently diagnosed with such a disease. A retrospective review of the histopathological findings was conducted to evaluate and reclassify all previous observations of abnormalities.

RESULTS

One hundred and five femoral heads demonstrated abnormal or reactive histopathological features not reported prior to surgery and were rejected for allograft use. A reactive lymphocytic infiltrate, most likely due to osteoarthritis, was the most commonly identified feature (forty-five cases). Other features observed in twenty-seven cases were also most likely due to the presence of severe osteoarthritis. Ten femoral heads demonstrated plasmacytosis, which may have been related to osteoarthritis. Two patients were diagnosed with Paget's disease, and two, with rheumatoid arthritis. Nineteen patients had a suspected neoplasm. Of these nineteen, eight cases of non-Hodgkin's lymphoma or chronic lymphocytic leukemia and one case of myelodysplastic syndrome were confirmed on further investigation. One subsequently confirmed malignancy was detected per 770 femoral heads examined.

CONCLUSIONS

Our findings indicate that, even with a detailed medical history and careful physical examination, clinically important diseases including neoplasms and Paget's disease are observed in patients diagnosed with osteoarthritis prior to total hip arthroplasty. Histological examination plays an integral role in quality assurance in femoral head banking, and it also represents a possible early diagnostic test for bone and bone-marrow-related diseases in patients undergoing total hip arthroplasty.

T and B lymphocyte abnormalities in bone marrow biopsies of common variable immunodeficiency

In common variable immunodeficiency (CVID) defects in early stages of B-cell development, bone marrow (BM) plasma cells and T lymphocytes have not been studied systematically. Here we report the first morphologic and flow cytometric study of B- and T-cell populations in CVID BM biopsies and aspirates. Whereas the hematopoietic compartment showed no major lineage abnormalities, analysis of the lymphoid compartment exhibited major pathologic alterations. In 94% of the patients, BM plasma cells were either absent or significantly reduced and correlated with serum immunoglobulin G levels. Biopsies from CVID patients had significantly more diffuse and nodular CD3(+) T lymphocyte infiltrates than biopsies from controls. These infiltrates correlated with autoimmune cytopenia but not with other clinical symptoms or with disease duration and peripheral B-cell counts. Nodular T-cell infiltrates correlated significantly with circulating CD4(+)CD45R0(+) memory T cells, elevated soluble IL2-receptor and neopterin serum levels indicating an activated T-cell compartment in most patients. Nine of 25 patients had a partial block in B-cell development at the pre-B-I to pre-B-II stage. Because the developmental block correlates with lower transitional and mature B-cell counts in the periphery, we propose that these patients might form a new subgroup of CVID patients.

Megakaryocyte-bone marrow stromal cell aggregates demonstrate increased colony formation and alkaline phosphatase expression in vitro

Bone marrow stromal cells (BMSCs) possess certain stem celllike properties and can differentiate to adopt a number of mesenchymal phenotypes. BMSCs are usually investigated in vitro as homogeneous single-cell suspensions; however, these preparations lose much of their osteogenic capacity. Using the fibroblastic colony-forming unit assay, we have compared the proliferation and capacity to express alkaline phosphatase of BMSC-containing aggregates of bone marrow cells with single-cell suspensions of bone marrow cells from the same source. Aggregates were separated from single cells by density gradient centrifugation or cell sieving. The aggregate and single-cell preparations gave rise to similar numbers of colonies; however, the colonies produced by the aggregates were larger and expressed higher levels of alkaline phosphatase. When the aggregates were dissociated, colonies still formed; however, they expressed negligible levels of alkaline phosphatase. Immunomagnetic selection and immunofluorescent staining for CD61, N-methyl-D-aspartate (NMDA) receptor subunit 1, and acetylcholinesterase showed that the majority of the aggregates giving rise to osteoblastic colonies contained megakaryocytes. These data demonstrate that removing BMSCs from their normal environment reduces their osteoblastic capacity and that to achieve their maximal differentiation, BMSCs require direct physical contact with accessory cells such as megakaryocytes. These findings may be of direct relevance to the use of BMSCs for tissue-engineering purposes.

A comparison of flow cytometry, bone marrow biopsy, and bone marrow aspirates in the detection of lymphoid infiltration in B cell disorders

AIMS

To evaluate the diagnostic value of bone marrow aspirates, trephine biopsies (BMB), and flow cytometry (FC) in the assessment of bone marrow infiltration in chronic lymphoid disorders.

METHODS

Investigations were carried out in 110 diagnostic and follow up specimens from B cell disorders, namely: chronic lymphocytic leukaemia (CLL; 65), non-Hodgkin's lymphoma (NHL; 39), and hairy cell leukaemia (HCL; 6). A selected panel of monoclonal antibodies was used both for FC and immunohistochemistry.

RESULTS

In CLL there was agreement between the three investigations in 71% of samples and in 88% when only FC and BMB were compared. In nine of 65 samples, FC and BMB were positive, although the aspirate was reported as negative. Four BMB negative samples had minimal residual disease (MRD) detected by FC, whereas two samples were positive both on BMB and aspirate but showed no evidence of disease on FC. In NHL, there was agreement between the three investigations in 22 of 39 cases, and in 27 of 39 cases there was agreement between FC and BMB. In eight of 39 NHL cases, FC was negative but the BMB was either positive (five) or uncertain (three), whereas in three of 39, FC was positive but BMB was either negative (one) or uncertain (two). In three of five uncertain BMB, no clonal population was detected by the polymerase chain reaction, whereas in the remaining two cases the nodular aggregates disappeared on further sectioning.

CONCLUSIONS

Both BMB and FC are better than bone marrow aspirates for the detection of infiltration in B cell disorders. FC might be slightly more sensitive than BMB to detect MRD in CLL, whereas BMB may be slightly better than FC in NHL.

Follicular pattern of bone marrow involvement by follicular lymphoma

Five patterns of bone marrow infiltration by non-Hodgkin lymphoma or Hodgkin lymphoma are currently recognized, but a true follicular pattern of bone marrow involvement by follicular lymphoma has not been described. In 260 bone marrow trephine biopsy specimens involved by follicular lymphoma, we identified 12 cases with a follicular pattern of bone marrow involvement. The paratrabecular pattern was not present at all in 9, and it accounted for less than 10% of tumor burden in 3 cases. Malignant follicles in the bone marrow were similar to malignant follicles in the respective lymph nodes. Follicular dendritic cells were identified by immunohistochemical analysis. The true follicular pattern of bone marrow involvement by follicular lymphoma seems to be more frequent in women than in men. It is important to recognize this pattern of follicular lymphoma in the bone marrow because it is possible to misinterpret interstitial lymphoid aggregates as benign in the absence of the more characteristic paratrabecular pattern.

Bone marrow lymphoid aggregates in myelodysplastic syndromes: incidence, immunomorphological characteristics and correlation with clinical features and survival

Lymphoid aggregates (LA) are a common finding in bone marrow biopsies but little is known about their clinical implications and biological significance. We found LA in 51/206 patients with myelodysplastic syndromes (MDS). There was no correlation with age, disease progression or overall survival. The group with LA had lower hemoglobin values (P=0.03), and was associated with an increase in reticulin fibres (P=0.01). Although they were more frequent in RAEB, this did not reach statistical significance. Most LA had a benign morphology and showed CD20 expression in three distinct patterns: central, perinodular or diffuse. No evidence of an association with lymphoproliferative disease was observed. LA probably represent an ongoing immune stimulation and are probably related to an altered bone marrow microenvironment, with no impact on prognosis.

Bone marrow manifestations of infections and systemic diseases observed in bone marrow trephine biopsy review

Bone marrow modifications resulting from infections and systemic diseases can be studied by analysis of morphology and aetiology. Two types of lesions or modifications can be observed, those occurring in the connective tissue comprising inflammatory processes, acute and chronic, as well as immune reactions, and those involving the normal haematopoietic cell lines, with possible hyperplastic or aplastic changes in one or more cell lines. The main lesions are described (oedema, haemorrhage, necrosis, suppuration, granulomas, lymphoid nodules and hyperplasia, immunoblastic or plasmacytic hyperplasia), as well as the main aetiologies. In association, the three main haematopoietic cell lines show hyperplasia, hypoplasia, aplasia of one or all of the cell lines, sometimes with dysmyelopoiesis. The stroma and vessel reactions comprise myelofibrosis, gelatinous transformation or amyloid deposits. The methods for identifying aetiological agents are emphasized. It should also be stressed that malignant neoplasias of different types involving the bone marrow can be responsible for such inflammatory or immune reactions.

Can polymerase chain reaction help distinguish benign from malignant lymphoid aggregates in bone marrow aspirates?

OBJECTIVE

Although morphologic and immunologic clues are helpful in distinguishing benign from malignant lymphoid aggregates in bone marrow biopsies, there remain some cases in which it is not possible to arrive at a definitive diagnosis. Since the malignant aggregates are monoclonal B-cell proliferations, we sought to determine whether performing polymerase chain reaction for the immunoglobulin heavy-chain locus would be helpful in distinguishing these 2 entities.

METHODS AND RESULTS

Scrapings from unstained bone marrow aspirate smears or touch preparations of bone marrow biopsies from 15 patients with benign bone marrow lymphoid aggregates and 18 patients with malignant lymphoid infiltrates were analyzed for rearrangements of the FR3 region of the immunoglobulin heavy-chain gene locus by a heminested polymerase chain reaction procedure. All specimens had amplifiable DNA, as shown by amplification of the ras proto-oncogene. None of the 15 cases of benign bone marrow lymphoid aggregates demonstrated clonality upon amplification of the immunoglobulin heavy-chain gene locus. In contrast, 8 of the 18 malignant samples were positive (P =.01 by chi(2) test; sensitivity, 44%; specificity, 100%; positive predictive value, 100%; negative predictive value, 60%). There was a tendency for there to be more lymphocytes in stained bone marrow aspirate smears from the cases of malignant lymphoid aggregates with a positive polymerase chain reaction result than in those without demonstrable clonality (36.0 +/- 35.4% vs 9.8 +/- 8.0%, P =.13).

CONCLUSIONS

Polymerase chain reaction for the immunoglobulin heavy-chain gene locus may help distinguish benign from malignant bone marrow lymphoid aggregates. Although the presence of false-negative samples may be related to the relative lack of lymphocytes in the bone marrow aspirates, other factors, such as the lack of amplification of the FR3 region of the immunoglobulin heavy-chain gene locus in particular tumors, cannot be ruled out with certainty.

Focal lymphoid aggregates (nodules) in bone marrow biopsies: differentiation between benign hyperplasia and malignant lymphoma--a practical guideline

AIMS

To provide practical guidelines for the differentiation between benign and malignant focal lymphoid aggregates (lymphoid nodules) in routinely referred bone marrow trephine biopsies, using a synoptic approach including clinical data and histological workup.

METHODS

For easy identification of very small lymphoid infiltrates the chloroacetate esterase stain was applied as a screening procedure. This allowed the identification of 491 formalin fixed, paraffin wax embedded specimens with one or more lymphoid nodules. Examination of lymphoid infiltrates included such variables as histotopography, demarcation, cytology, reticulin fibres, and immunohistochemistry with a set of monoclonal antibodies (CD20, CD45R, CD45R0, CD3, CD43). Evaluation of clinical and morphological data was carried out independently. In case of malignant lymphomas, a correlation with corresponding lymph node findings was made.

RESULTS

352 patients had benign focal lymphoid aggregates usually associated with systemic autoimmune diseases, chronic myeloproliferative disorders, toxic myelopathy, and viral infections. Discrete nodular infiltrates of (small cell) malignant lymphomas (n = 93) simulating benign hyperplasia were found in chronic lymphocytic leukaemia, germinal centre cell lymphomas (CB-CC), and lymphoplasmacytic/cytoid lymphomas (LPI). In addition to immunoreactivity, certain histological variables proved distinctive. These were: (1) histotopography, that is, localisation of the lymphoid aggregates within the bone marrow space; (2) relation to the surrounding tissue: margination or interstitial spillage of lymphoid cells; and (3) increase in reticulin fibres.

CONCLUSIONS

A combined diagnostic procedure identifying several distinctive features, in particular histotopography and immunohistochemistry, provides a most promising way of discriminating reactive from neoplastic lymphoid nodules in the bone marrow.

Three-dimensional reconstruction of benign lymphoid aggregates in bone marrow trephines

Distinguishing between deposits of low-grade non-Hodgkin's lymphoma and benign lymphoid aggregates in bone marrow trephine sections is a recognized problem in haematopathology. To test the hypothesis that benign lymphoid aggregates do not make contact with a trabecular surface, three-dimensional models were constructed of five serially sectioned bone marrow trephines, containing a total of 19 lymphoid aggregates known to be benign. The computer-generated images showed that benign lymphoid aggregates were located in the central marrow space and did not become paratrabecular. This suggests that a paratrabecular location may help in some cases to distinguish deposits of low-grade non-Hodgkin's lymphoma from benign lymphoid aggregates.

The bone marrow trephine biopsy: a review of normal histology

Bone marrow trephine biopsies are becoming increasingly common in routine surgical pathology. Familiarity with normal marrow histology plays an important part in understanding and interpreting marrow pathology. The aim of this article is to describe the histological features of normal human bone marrow, in particular those features which are relevant to the diagnostic pathologist. The advantages and disadvantages of different technical aspects, such as choice of embedding material and type of stain, are discussed. The use of immunochemistry in identifying different cell types within the marrow is illustrated.

Histology of normal haemopoiesis: bone marrow histology. I

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Incidence and prognostic significance of blood lymphocyte clonal excess in localized non-Hodgkin's lymphoma

Despite elaborate staging procedures, a substantial number of patients with localized NHL experience dissemination after local therapy, indicating that current routine methods are insufficient to detect tumour spread. We have used flow cytometric clonal excess (CE) analysis of peripheral blood in conjunction with routine staging procedures to study the occurrence of occult leukaemic spread in patients with localized NHL stages I, IE and IIE. CE in peripheral blood was a rare finding, identified in only 11% (14/130), and slightly more frequent in low-grade NHL, 20% compared to high-grade NHL, 7%. There was no correlation to any of the other major prognostic factors studied. Occult tumour spread would suggest an increased risk of relapse and possibly a decreased survival after local therapy. Among 93 patients given only local treatment there was an increased risk of relapse in those with low-grade malignant lymphomas and CE, which was not found in patients with high-grade malignant lymphomas and CE. CE in peripheral blood had no influence on survival in either of the histologic groups. A tentative explanation is that circulating lymphoma cells represent indolent populations irrespective of the histology of the primary tumour. The malignant nature of such a lymphoma spread might not be obvious during this rather limited follow-up of a median 34 months. The clinical interpretation is that the existence of CE in peripheral blood in patients with localized high-grade NHL should have no influence on the choice of therapy. In localized low-grade lymphoma the same therapeutic attitude which applies to widespread disease might be considered.

Immunohistochemical evaluation of bone marrow lymphoid nodules in chronic myeloproliferative disorders

One hundred and seventy bone marrow biopsies from patients with chronic myeloproliferative disorders (CMPDs) were evaluated for the presence of lymphoid nodules (LNs) and were immunostained using a panel of monoclonal antibodies (UCHL1, 4KB5 and L26) recognizing different lymphocyte antigens. LNs were found in 35% of cases of idiopathic thrombocythaemia, 24.6% of myelofibrosis/osteomyelosclerosis, 18.2% of polycythaemia vera 12.1% of chronic myeloid leukaemia and 19.2% of borderline cases. Varying degrees of immunohistochemical positivity for the three antibodies tested were found. LNs were always made up of variable proportions of both T- and B-lymphocytes with a prevalence of T-cells. This latter observation suggests that bone marrow LNs in CMPDs could be an expression of reactivity.

Reticulin fibre content of bone marrow infiltrates of malignant non-Hodgkin's lymphomas (B-cell type, low malignancy)--a morphometric evaluation before and after therapy

A morphometric study was performed on bone marrow infiltrates of non-Hodgkin's lymphomas (B-cell type, low malignancy) to evaluate the content of argyrophilic (reticulin) fibres in the various subtypes before and after therapy. In congruence with the corresponding lymph node lesions, subtypes consisted of lymphocytic lymphoma--chronic lymphocytic leukaemia (CLL, n = 39), centroblastic-centrocytic lymphoma (CB-CC, n = 35), lymphoplasmacytoid immunocytoma (LPI, n = 22) and finally hairy cell leukaemia (HCL, n = 21). In comparison with control specimens, morphometric measurements on trephine biopsies (initial staging procedure) disclosed a borderline or minimal increase in reticulin in CLL and moderate fibrosis in CB-CC and LPI, whereas HCL had the greatest increase in fibres. The marrow surrounding focal or patchy lymphoma infiltrates of CLL and CB-CC displayed no relevant changes in fibre density with respect to the control samples. Following chemotherapy, repeated trephine biopsies (restaging procedure) were obtainable from 38 patients. There was no significant decrease in the fibre content of CLL, CB-CC and LPI infiltrates. In HCL an incomplete reduction was recorded after interferon treatment. So-called benign lymphoid lesions may be distinguished from focal-patchy infiltrates of CB-CC and LPI not only by showing a central localization, but also by the absence of significant amounts of reticulin. However, considering the density of the reticulin fibres, a clear-cut discrimination of these lymphoid aggregates from an early nodal-central growth pattern of CLL is not feasible in many cases.