To retrospectively evaluate the significance of morphologic examination and ancillary studies performed on bilateral bone marrow biopsy specimens, 1864 bone marrow samples were studied.
To retrospectively evaluate the significance of morphologic examination and ancillary studies performed on bilateral bone marrow biopsy specimens, 1864 bone marrow samples were studied.
Bilateral bone marrow biopsy specimens included 883 specimens that were evaluated for involvement by non-Hodgkin lymphoma (NHL); 381 specimens that were evaluated for involvement by carcinoma (CA); 362 specimens that were evaluated for involvement by Hodgkin disease (HD); 94 specimens that were evaluated for involvement by sarcoma (SA); 56 specimens that were evaluated for involvement by multiple myeloma (MM); 53 specimens that were evaluated for involvement by acute and chronic leukemia, myelodysplasia, and/or myeloproliferative disorders (LEUK); and 35 specimens that were evaluated for other reasons.
Of all 1864 specimens, 410 samples (22.0%) were positive for disease, including 77% of MM samples, 58% of LEUK samples, 29.6% of NHL samples, 14% of SA samples, 9.9% of HD samples, and 6.8% of CA samples. A discrepancy between the left and right sides was identified in 48 specimens (11.7% of positive samples). The discrepancy rate was 39% for HD samples, 29% for SA samples, 23% for CA samples, and 9.2% for NHL samples. No morphologic discrepancies between bilateral samples were found in MM samples or LEUK samples. Bilateral flow cytometric studies (n = 113 samples) were positive in 11 samples (9.7%; all morphologically positive), with two discrepancies detected between bilateral samples. Bilateral cytogenetic studies (n = 74 samples) were positive in 5 samples (7%), and there were no discrepancies. Bilateral molecular studies (n = 16 samples) were positive in 7 samples (44%), and there were 3 discrepancies.
Bilateral morphologic evaluation is useful in the evaluation of patients with NHL, HD, CA, and SA and is not indicated for patients with acute or chronic leukemia, myelodysplasia, MM, and other diseases. Bilateral flow cytometric or cytogenetic studies of bone marrow did not provide additional information in this population to justify bilateral samples. The role of bilateral molecular analysis needs to be defined further, but pooled samples for molecular studies may be adequate. Cancer 2002;94:1522–31. © 2002 American Cancer Society.
Bone marrow examination is performed commonly to evaluate for the presence of possible hematologic disorders as well as focal disorders, including involvement by metastatic tumors. The bone marrow trephine and clot biopsy are particularly useful in identifying focal lesions that may be less apparent on aspirate smears alone. The bone marrow biopsy is also a common and important staging procedure that is performed routinely on patients with hematologic and nonhematologic malignancies.1–4 Because of the focal nature of some of the diseases that involve the bone marrow, routine bilateral bone marrow biopsy examination has been advocated and practiced in the staging of patients with certain hematologic and nonhematologic disorders.5–12 Morphologic examination of a second biopsy reportedly increases the detection of bone marrow involvement by 11–22%.5 The value of nonmorphologic bilateral bone marrow ancillary studies, however, has not been studied as well as morphologic examination. We report our experience with morphologic evaluation of 1864 bilateral bone marrow biopsy specimens that were reviewed at the City of Hope National Medical Center from 1989 to 2000. The results of bilateral flow cytometric, cytogenetic, and molecular genetic studies also were reviewed on these specimens to assess the utility of performing bilateral ancillary bone marrow studies and to compare these studies with the morphologic evaluation.
Patients were identified by a computer search of specimens in the pathology files of the City of Hope National Medical Center from 1989 to 2000. All patients from City of Hope with bilateral biopsy material reviewed were included. Results of morphologic review and ancillary testing were obtained by review of the original pathology report. For each patient, right and left trephine biopsy specimens as well as available Wright–Giemsa-stained bone marrow aspirate and peripheral blood smears were evaluated in the original specimen work-up for involvement by malignancy. The trephine biopsies were fixed in formalin or B5, and 4–5-μm sections were stained routinely with hematoxylin and eosin. Each specimen was considered positive only if it could be diagnosed as involved unequivocally with the neoplastic process on trephine or clot biopsy material. Bone marrow specimens were evaluated for involvement by non-Hodgkin lymphoma (NHL) based on previously established criteria; specimens were defined as positive, negative, or indeterminate/suspicious.13 Diagnostic groups were determined by the clinical suspicion raised at the time of the bone marrow examination and by a review of previous and subsequent diagnostic material from the patient.
Results of bilateral ancillary studies on aspirate samples taken at the time of bilateral biopsy, including flow cytometric studies, molecular genetic analyses (polymerase chain reaction and/or Southern blot analysis), and classic or molecular (fluorescence in situ hybridization [FISH]) cytogenetic studies, also were evaluated. Flow cytometric studies were performed on separate cell suspensions of the bilateral bone marrow aspirates as described previously.14, 15 Older samples were analyzed using two-color flow cytometric analysis, whereas, after 1995, samples were analyzed by three-color analysis with CD45 gating.16 Bilateral molecular genetic studies were performed originally by Southern blot analysis and later using the polymerase chain reaction directed against gene rearrangements or balanced cytogenetic translocations specific for the tumor type.17, 18 Banded chromosomes were analyzed using standard methods and were identified using GTG banding. At least 20 metaphases were examined from each sample. Karyotyping and clonal definitions followed the International System for Cytogenetic Nomenclature 1995 criteria.19 Normal male or female karyotypes and constitutional abnormalities were considered negative. FISH studies were performed on selected samples using probes specific for a given tumor.20
One thousand eight hundred sixty-four bone marrow biopsy specimens with bilateral biopsies were identified. These included 883 specimens that were submitted for evaluation of bone marrow involvement by NHL, 381 specimens that were evaluated for involvement by carcinoma (CA), 362 specimens that were evaluated for involvement by Hodgkin disease (HD), 94 specimens that were evaluated for involvement by sarcoma (SA), 56 specimens that were evaluated for involvement by multiple myeloma (MM), 53 specimens that were evaluated for involvement by acute and chronic leukemia/myelodysplasia/myeloproliferative disorders (LEUK), and 35 specimens that were evaluated for other reasons (the Other group). The morphologic and bilateral ancillary findings are summarized in Tables 1–7.
A total of 410 bone marrow biopsy specimens (22.0%) were involved by malignancy, and 45 specimens (2.4%) were considered to have areas suspicious or indeterminate for disease (Table 1). Unilateral involvement was identified in 48 specimens (23 right-sided specimens and 25 left-sided specimens), representing 2.6% of all specimens and 11.7% of positive specimens. There were 20 specimens with only unilateral areas suspicious for disease (10 right-sided specimens and 10 left-sided specimens), representing 44% of all suspicious/indeterminate specimens.
|Diagnosis||No evidence of malignancy in bone marrow||Suspicious/indeterminate for malignancy in bone marrow biopsies||Malignancy present on bone biopsies||Total no. of specimens|
|Non-Hodgkin lymphoma (%)||583||39 (9R, 9L, 21B) (4.4%)||261 (12R, 12L, 237B) (29.6%)||883|
|Carcinoma||355||None||26 (4R, 2L, 20B) (6.8%)||381|
|Hodgkin disease||320||6 (1R, 1L, 4B) (1.7%)||36 (5R, 9L, 22B) (9.9%)||362|
|Sarcoma||81||None||13 (2R, 2L, 9B) (14%)||94|
|Multiple myeloma||13||None||43 (0R, 0L, 43B) (77%)||56|
|Leukemia/myelodysplasia||22||None||31 (0R, 0L, 31B) (58%)||53|
|Total (%)||1409 (75.6)||45 (2.4)||410 (22.0)||1864|
Eight hundred eighty-three specimens to rule out bone marrow involvement by NHL were evaluated. The patients had previously diagnosed NHL disease categories that included follicular lymphoma (187 patients), diffuse large cell lymphoma (170 patients, including 18 patients with immunoblastic disease), mantle cell lymphoma (71 patients), peripheral T-cell lymphoma (51 patients), Burkitt-like/Burkitt lymphoma (33 patients), small lymphocytic lymphoma/chronic lymphocytic leukemia (26 patients), lymphoblastic lymphoma (24 patients), marginal zone B-cell lymphoma (21 patients), hairy cell leukemia (4 patients), lymphoplasmacytic B-cell lymphoma (2 patients), and composite lymphoma (1 patient), and 293 specimens were submitted to rule out malignant lymphoma, not otherwise specified (NOS). Of the 883 patients, 583 had no evidence of lymphoma involvement in bilateral bone marrow specimens. Bone marrow involvement was found in 261 specimens (29.6%), with 237 specimens (90.8%) bilaterally positive and 24 specimens (9.2%) unilaterally positive only (Tables 1 and 3). A discrepancy between the two sides, therefore, was identified in 24 specimens by morphologic evaluation (Tables 3 and 4). In addition, 39 specimens (4.4% of total; 21bilateral specimens, 9 right-sided specimens, and 9 left-sided specimens) were suspicious/indeterminate for bone marrow involvement (Table 1). Bone marrow involvement was most common in patients with small lymphocytic lymphoma/chronic lymphocytic leukemia (92%), mantle cell lymphoma (58%), and follicular lymphoma (44.4%), and unilateral involvement was most common in patients with peripheral T-cell lymphoma (15% of positive specimens), follicular lymphoma (8%), and mantle cell lymphoma (7%) (Table 2).
|Disease type||No.||Total no. positive (%)||No. unilateral positive (% of total; % of positive results)|
|Follicular lymphoma||187||83 (44.4)||7 (0.4; 8)|
|Large cell lymphoma||170||28 (16.5)||1 (0.6; 4)|
|Mantle cell lymphoma||71||41 (58)||3 (4; 7)|
|Peripheral T cell lymphoma||51||13 (25)||2 (4; 15)|
|Burkitt lymphoma||33||3 (9)||0|
|Small lymphocytic lymphoma/chronic lymphocytic leukemia||26||24 (92)||0|
|Lymphoblastic lymphoma||24||6 (25)||0|
|Marginal zone lymphoma||21||6 (29)||0|
|Breast||355||21 (5.9)||5 (1.4; 24)|
|Others (nonbreast)||26||5 (19)||1 (4; 20)|
|Small blue round cell sarcomasb||81||14 (17)||4 (5; 29)|
|Diagnosis||Bilateral (%)||Unilateral (%)||Total positive||Percentage of total|
|Non-Hodgkin lymphoma||237 (90.8)||24 (9.2)||261||29.6|
|Carcinoma||20 (77)||6 (23)||26||6.8|
|Hodgkin disease||22 (61)||14 (39)||36||9.9|
|Sarcoma||9 (64)||4 (29)||13||14|
|Total||362 (88.3)||48 (11.7)||410||22.0|
|Diagnosis||Right side||Left side|
|Diffuse large cell lymphoma||2||0|
|Mantle cell lymphoma||0||4|
|Small lymphocytic lymphoma/chronic lymphocytic leukemia||1||0|
|Peripheral T-cell lymphoma||1||0|
|Lymphoma, not otherwise specified||5||2|
|Not otherwise specified||0||2|
Of the 362 patients with HD, 320 patients (88.4%) had no evidence of bone marrow involvement by HD on bilateral bone marrow specimens. Tables 1 and 3 show that HD involvement was found in 36 specimens (9.9%), with 22 specimens (61%) showing bilateral bone marrow involvement and 14 specimens (39%) showing only unilateral bone marrow involvement (5 right-sided specimens and 9 left-sided specimens) (Tables 1–4. Six specimens (1.7% of all) (four bilateral specimens, one right-sided specimen, and one left-sided specimen) were suspicious/indeterminate for bone marrow involvement by HD (Table 1).
Three hundred eighty-one patients were evaluated for bone marrow involvement by different CA types, including possible bone marrow involvement by breast CA (355 patients), small cell CA of the lung (8 patients), adenocarcinoma of the prostate (2 patients), ovarian CA (2 patients), germ cell tumor (2 patients), carcinoid (1 patient), colorectal CA (1 patient), neuroendocrine CA (1 patient), and CA of unknown origin (9 patients). Of these, 26 patients (6.8%) showed morphologic evidence of bone marrow metastasis, with 20 specimens (77% of positive specimens) showing bilateral bone marrow involvement and 6 specimens (23% of positive specimens) showing only unilateral bone marrow involvement (4 right-sided specimens and 2 left-sided specimens) (Tables 1–4. Of the positive bone marrow samples, 21 samples involved breast CA (18 samples involved infiltrating ductal CA, and 3 samples involved infiltrating lobular CA), 2 samples involved small cell CA of the lung, 2 samples involved CA unknown sites, and 1 sample involved prostatic adenocarcinoma.
Ninety-four patients who were evaluated for involvement by various types of SA were identified. These included neuroblastoma (31 patients); Ewing SA (22 patients); rhabdomyosarcoma (13 patients); SA, NOS (7 patients); primitive neuroectodermal tumor (6 patients); medulloblastoma (5 patients); Wilms tumor (2 patients); malignant fibrous histiocytoma (2 patients); and 1 patient each with desmoplastic small round blue cell tumor, epithelioid SA, ganglioneuroblastoma, leiomyosarcoma, glioblastoma multiforme, and synovial SA. Of the 94 SA specimens, 81 specimens (86%) had no evidence of bone marrow involvement. In 13 patients (14%), metastatic SA was found in bone marrow specimens by morphologic evaluation. Of the positive bone marrow samples, eight were neuroblastomas, three were Ewing SAs, one was medulloblastoma, and one was rhabdomyosarcoma. Nine of 13 morphologically positive specimens (69%) were bilateral, including 6 neuroblastomas, 2 Ewing SAs, 1 medulloblastoma, and 1 rhabdomyosarcoma. The remaining four specimens (31%), which included three with neuroblastoma and one with Ewing SA, were involved only unilaterally (two specimens on each side) (Tables 1–4.
A total of 56 patients with MM were identified, and 43 patients (77%) had biopsy specimens that demonstrated bone marrow involvement. All showed bilateral involvement by morphologic examination (Tables 1–4.
Fifty-three patients were identified in the LEUK group. These included patients with specimens submitted for the evaluation of involvement by acute myeloid leukemia (17 patients), acute lymphoblastic leukemia (15 patients), chronic myelogenous leukemia (7 patients), myelodysplasia (9 patients), and other myeloproliferative disorders (5 patients). Morphologic evidence of disease was found in 31 specimens (58%), and all were involved bilaterally.
Thirty-five other patients had bilateral bone marrow examination performed to evaluate for the presence of nonneoplastic disorders, including biopsies for aplastic anemia (5 patients), anemia (3 patients), hypereosinophilia (3 patients), lymphadenopathy (3 patients), idiopathic thrombocytopenic purpura (3 patients), acquired immunodeficiency syndrome (1 patient), cystic fibrosis (1 patient), Schwachman–Diamond syndrome (1 patient), infection (1 patient), and 14 patients with unknown diagnoses. No morphologic evidence of malignancy was seen in any of the specimens from these patients, although features consistent with nonneoplastic disease changes were identified in some specimens.
A total of 113 patients had bilateral flow cytometry studies, with 11 positive results (9.7%) (Table 5). All positive results were found in specimens that were positive by morphology; 41% (11 of 27 specimens) of morphology positive specimens with bilateral flow cytometry performed were positive according to this latter technique.
Five hundred twenty-eight of the patients who were evaluated for the presence of NHL had flow cytometry studies. Bilateral flow cytometry samples were submitted for 88 patients, including 64 bilateral morphologically negative samples, 19 bilateral morphologically positive samples, 3 unilateral morphologically positive samples, and 2 unilateral morphologically suspicious/indeterminate samples. All 64 morphologically bilateral negative samples showed no abnormal bilateral flow cytometric findings. Nine of 19 bilateral, morphologically positive samples (47%) also were positive according to flow cytometric analyses, with 8 of 9 positive samples in bilateral flow cytometric specimens. There was one specimen of follicular lymphoma with bilateral morphologic involvement that was positive only unilaterally according to flow cytometry. In addition, there were three specimens with unilateral morphologic bone marrow involvement studied by bilateral flow cytometry, and all were negative by bilateral flow cytometry.
None of the 104 samples that were submitted to rule out HD by flow cytometry studies demonstrated diagnostic abnormalities. This included 11 bilateral, morphologically negative samples.
Of 24 patients who underwent flow cytometric studies in the LEUK group, 4 patients had bilateral flow cytometric studies, which resulted in 2 morphologically negative samples and 2 morphologically positive samples. None of the two morphologically negative samples showed bilateral flow cytometric abnormalities. Both of the bilateral, morphologically positive samples showed flow cytometric abnormalities, with bilateral flow cytometric abnormalities detected in one samples and only unilateral abnormalities detected in the other sample.
Of the 20 patients with MM who underwent flow cytometric studies, only 2 patients had bilateral flow cytometric studies (both morphologically positive). Neither showed flow cytometric abnormalities.
There were two samples in the CA group (both morphologically negative) and three samples (two morphologically negative and one morphologically positive) in the SA group that were submitted for bilateral flow cytometric studies. In addition, flow cytometry studies were performed in a total of 19 samples from in the Other group, of which only 3 samples were analyzed with bilateral flow cytometry. No diagnostic abnormalities were identified in any of these samples.
A total of 16 patients had bilateral molecular studies, and 7 patients (44%) had positive results. Three of 6 patients had morphologically positive results, and 4 of 10 patients had morphologically negative results (Table 6).
Of 205 specimens that were obtained to rule out NHL and were studied by molecular analysis, 13 specimens underwent bilateral molecular studies. These included nine bilateral, morphologically negative specimens; three bilateral, morphologically positive specimens; and one unilateral, morphologically positive specimen. Of the four morphologically positive specimens, one specimen showed both bilateral morphologic and molecular abnormalities, and a second specimen showed bilateral morphologic involvement but only unilateral positivity in bilateral molecular studies. In contrast, bilateral molecular abnormalities were detected in two of nine bilateral, morphologically negative specimens, and only unilateral molecular abnormalities were detected in two bilateral, morphologically negative specimens.
In the LEUK group, bilateral molecular studies were performed on only one bilateral, morphologically positive specimen, and no molecular abnormality was identified. Bilateral molecular analysis was performed on only one bilateral, morphologically positive MM specimen, in which clonal immunoglobulin heavy-chain gene rearrangements were demonstrated on both sides.
In the SA group, the results of bilateral molecular analysis were available for only one bilateral, morphologically negative specimen, and no abnormal finding was identified. No bilateral molecular studies were performed on any of the specimens that were evaluated in the HD group, the CA group, or the Other group.
A total of 74 specimens had bilateral cytogenetic studies. Of these, five specimens (7%) were positive, all of which were bilateral (Table 7) and were positive by morphology. These represented 5 of 16 morphologically positive specimens (31%).
Cytogenetic studies were performed in a total of 509 specimens from the NHL group, and 24 specimens from this group had bilateral cytogenetic studies. These latter 24 specimens included 5 bilateral, morphologically positive specimens; one unilateral, morphologically involved specimen; and 18 bilateral, morphologically negative specimens. Only 1 of 6 morphologically positive specimens (17%) showed cytogenetic abnormalities, whereas 0 of 18 morphologically negative specimens showed bilateral cytogenetic abnormalities.
Of the 170 HD specimens that were subjected to cytogenetic studies, 12 specimens underwent bilateral cytogenetic analyses, including 2 bilateral, morphologically positive specimens; 1 unilateral, morphologically positive specimen; and 9 bilateral, morphologically negative specimens. Cytogenetic abnormalities were found in only one of the two bilateral, morphologically positive specimens; all of the other specimens showed no cytogenetic abnormalities.
In the LEUK group, 21 specimens were subjected to cytogenetic studies, but bilateral cytogenetic results were available for only 5 specimens. These included three bilateral, morphologically positive specimens, of which only one specimen showed bilateral cytogenetic abnormalities, and the other two did not show any cytogenetic abnormalities. The two morphologically negative LEUK specimens also were negative for cytogenetic abnormalities.
Only two specimens (one bilateral, morphologically positive specimen and one bilateral, morphologically negative specimen) in the MM group underwent bilateral cytogenetic studies. Neither specimen them showed cytogenetic abnormalities.
Cytogenetic studies were performed on 191 specimens from the CA group, 12 of which were bilateral. One unilateral, morphologically positive specimen from the CA group had a clonal cytogenetic abnormality that was detected in bilateral samples. Cytogenetic abnormalities were not detected in any of the bilateral samples of the 11 morphologically negative specimens.
Cytogenetic studies were performed on 29 specimens from the SA group, 15 of which were bilateral. Bilateral cytogenetic abnormalities were detected in 1 of 2 bilateral, morphologically positive specimens and in 0 of 12 bilateral, morphologically negative specimens.
The results of cytogenetic studies were available for 21 specimens from the Other group, including 4 bilateral samples. None of the bilateral samples showed cytogenetic abnormalities; all were negative by morphology.
In summary, for the ancillary studies, bilateral flow cytometric studies (n = 113 patients) were positive in 9.7% of samples, and there were 2 discrepancies detected between bilateral samples. All bilateral, flow cytometric positive samples also were morphologically positive. Bilateral molecular studies (n = 16 patients) were positive in 44% of samples, and there were 3 discrepancies detected between the bilateral samples. Bilateral cytogenetic studies (n = 74 patients) were positive in 7% of samples, and there were no discrepancies detected between the bilateral samples.
The value of bone marrow aspiration and biopsy examination in evaluating disease stage in patients with hematologic and nonhematologic malignancies is well established, particularly for patients with malignant lymphoma, CA, and SA.3, 4, 21, 22 Bone marrow involvement has a significant impact on treatment and overall survival in many diseases. Several studies have addressed the utility of bilateral bone marrow biopsy morphologic examination in selected disease groups. In 1975, Brunning and colleagues5 reported their experience with bilateral bone marrow biopsies in 282 patients with lymphoma and other neoplastic diseases. That study found that the second biopsy identified an additional 11–22% of involved specimens by morphologic evaluation alone that would not have been recognized with unilateral bone marrow examination. Menon and Buchanan7 also found a 26% increase in disease detection when bilateral bone marrow biopsy morphology was compared with unilateral examination in a series of 145 patients with HD and NHL. Similarly, Juneja et al.8 found a 15% increase in detection with bilateral biopsies in a series of 260 patients with NHL, with the highest discrepancy rate occurring for patients with large cell lymphoma. In a study of 368 patients with different types of NHL, Luoni et al.9 found that bilateral studies increased the yield by 4–5%, resulting in a 0.7–2.8% upgrade in stage from Stage I–II to Stage IV. Almeida and associates10 also reported a discrepancy rate of up to 21% if only unilateral bone marrow biopsies were performed in their series of 104 bilateral specimens from 89 patients with lymphoproliferative disorders. Ebie and colleagues23 found only a 2.5% discrepancy rate when bilateral bone marrow biopsies were performed in patients with intermediate grade to high-grade lymphoma, and they suggested that the use of bilateral samples should be restricted to selected patients.
Although most of the studies on bilateral bone marrow examination relate to involvement by lymphoproliferative disorders, the increased yield due to bilateral examination in patients with CA and SA has been reported to be 4–25%.4, 5, 12 Those studies concluded that bilateral bone marrow biopsies should be performed routinely in the search for involvement by tumor in the bone marrow. It has been suggested that the performance of two biopsies at the same anatomic site to increase the yield of positivity is preferable to a single bone marrow biopsy,5 although the increased yield from ipsilateral examination was not as high as the yield from bilateral examination in one study.11 Therefore, routine bilateral bone marrow biopsy examination has been advocated and used by many in the search of bone marrow involvement by hematologic and nonhematologic malignancies.
The current, retrospective study found a 22.0% overall rate of bone marrow involvement by malignancy, with only unilateral disease involvement detected in 11.7% of the positive specimens. The second bone marrow biopsy increased the yield of the procedure by 4.6–19.5%. The discrepancies between bilateral samples by morphologic evaluation were 39% for HD, 29% for SA, 23% for CA, and 9.2% for NHL. For these four disease groups, there was an overall 13.3% frequency of unilateral bone marrow involvement. Assuming that random, unilateral sampling would identify only half of these specimens, bilateral biopsies would be expected to detect 19.5% more specimens with HD involvement, 14% more specimens with SA involvement, 11.5% more specimens with CA involvement, and 4.6% more specimens with NHL involvement. These findings confirm the diagnostic usefulness of morphologic evaluation of bilateral bone marrow biopsy samples in the staging process of patients with NHL, HD, CA, and SA. In contrast, we did not find discrepancies between bilateral samples in patients with MM, acute leukemia, or chronic myeloproliferative disorders by morphologic evaluation. Unilateral morphologic evaluation appears to provide sufficient information for assessing bone marrow involvement for the evaluation of these disease categories. Our results, however, do not clearly establish the frequency of unilateral or bilateral bone marrow involvement, because the clinical factors that lead to the decision to perform bilateral examination rather than unilateral biopsy were not considered. Only a prospective study with bilateral bone marrow biopsies performed on every patient with these diseases would provide a definitive incidence of the frequency of bilateral or unilateral bone marrow involvement in patients with these diseases.
Recently, the roles of flow cytometric immunophenotyping of blood and bone marrow and immunohistochemical paraffin section staining of bone marrow biopsies in the staging of tumors have been evaluated.21, 24–29 The role of bilateral bone marrow ancillary studies in the staging of malignancies has not been well studied in the literature. Flow cytometric immunophenotyping is a valuable tool in the primary diagnosis of leukemias and lymphomas, but its value in the detection of residual disease or in staging is more controversial. Comparisons of morphologic evaluation versus flow cytometry in the staging of patients with NHL generally have shown a fair correlation, with the percentage of patients with NHL detected by flow cytometry in the absence of morphologic features of disease ranging from 1.1% to 12%.26–29 We did not find any patients in whom flow cytometric detection of disease was accompanied by bilateral, morphologically negative examination. Hanson and colleagues28 compared morphologic examination with flow cytometry in 175 patients with NHL and found that 5 patients (2.8%) had negative morphologic results and positive flow cytometric results. Naughton et al.26 found a 1.1% rate of detection by flow cytometry in the absence of diagnostic morphologic evidence of disease in the staging of patients with NHL. Both of these studies concluded that routine flow cytometric studies for staging patients with lymphoma played a limited role in the evaluation of lymphoma and was not a cost-effective replacement for morphologic evaluation. In contrast, Duggan and associates29 studied 227 NHL staging samples by flow cytometry and compared them with morphologic examination. Those authors found that 12% of samples were negative in the morphologic examination and positive in the flow cytometric examination. They concluded that both flow cytometry and morphologic evaluation were needed in these types of specimens. The differences in results for staging patients with lymphoma using flow cytometry may reflect differences in methodology. Our study and most of the previously reported studies that found a limited utility for flow cytometry compared with morphology used older, two-color or three-color analysis methods. The study by Duggan et al.29 employed three-color and four-color, multiparameter flow cytometric analysis. Four-color analysis allows for more focused gating on B-cell populations and should allow for the detection of smaller clonal populations than the older gating strategies.
The issue of whether bilateral samples of bone marrow should be tested by flow cytometry has not been well studied. Our results suggest that separate bilateral samples are not necessary for flow cytometry. We consider that the submission of a unilateral sample for flow cytometry or the pooling of bilateral aspirate samples for a single flow cytometric specimen is adequate in conjunction with bilateral biopsy specimens.
The value of bilateral molecular genetic and cytogenetic studies also has not been well described in the literature. These methods provide valuable information for the classification of lymphomas and some leukemias and provide valuable prognostic information for many diseases.30–32 The use of molecular testing to evaluate post-therapy specimens for residual disease has become increasingly common.33 Coad et al.34 found an 11% rate of detection of clonal populations by molecular methods in patients with NHL and negative bone marrow morphology. Whether bilateral samples are needed to detect these abnormalities is less clear. Murphy and colleagues35 studied 140 patient samples for the evaluation of NHL with bilateral molecular studies and found a 2.9% rate of discrepancy between the two sides. Those authors recommended pooling samples rather than running samples separately. Our results from bilateral molecular studies are more limited but also suggest that molecular studies may provide information that complements morphologic examination. However, separately run bilateral samples may not be needed, and pooled samples for molecular genetic studies may be appropriate.
None of the morphologically negative specimens that underwent bilateral cytogenetic studies had cytogenetic abnormalities detected. Of the 74 specimens that underwent bilateral cytogenetic studies, no discrepancies were identified between the right-sided and left-sided cytogenetic samples, and no positive samples were identified in the absence of morphologic evidence of disease. The results, however, probably are biased, because only samples with bilateral bone marrow biopsies were included in the current study. Therefore, the percentages of samples of leukemia or myelodysplasia were relatively low in this study. Cytogenetic studies certainly play a role in the early detection of myelodysplastic syndromes that may be not be identified readily by morphology.36 Such abnormalities, however, would not require the collection of bilateral samples for detection. Therefore, we conclude that bilateral cytogenetic studies are not indicated. However, cytogenetic studies in these disease types are of value, and even the detection of a normal karyotype has prognostic implications in patients with acute leukemia.37 Unilateral samples or pooled bilateral samples appear to be adequate for most studies.
Although the false negative rate for the bilateral ancillary studies in this report appeared to be high, most of these differences were related to the focal nature of many of the diseases and the differences in specimen types (aspirates for ancillary studies and biopsies for morphology) that were compared. Because of the focal nature of bone marrow involvement in many patients with HD, NHL, metastatic CA, and SA, which comprised the great majority of disease types in this study, it is not surprising that many of these diseases were not evident in aspirate material alone.
In conclusion, our data indicate that bilateral morphologic bone marrow evaluation is useful for patients with NHL, HD, CA, and SA and is not indicated for patients with MM, acute and chronic leukemias, myelodysplasia, and other diseases. Bilateral flow cytometric or cytogenetic studies of bone marrow did not provide additional information in this population sufficient to justify separately analyzed, bilateral samples. Submission of unilateral samples for flow cytometric or cytogenetic analysis should be encouraged for patients with hematopoietic disorders, and pooling of samples, if bilateral specimens are submitted, appears to be appropriate. The value of bilateral molecular analysis in disease staging needs to be defined further, but it appears that the pooling of samples for molecular studies is a reasonable and cost-effective approach to the use of these methods.
The authors thank Ms. Gina Lewis for her secretarial assistance.