An Evaluation of Paraffin Sections of Aspirated Bone Marrow in Malignant Lymphomas

Examination of serial paraffin sections of bone-marrow aspirations has increased the known incidence of marrow involvement in malignant lymphomas. The results of this study can be seen in the table. In the 72 cases reviewed here, lesions compatible with malignant lymphoma were seen in paraffin sections in 22 cases. In 12 cases this was the only material available for diagnosis at the time. In an additional seven cases paraffin sections were considered suggestive of malignant lymphoma and in five of these a diagnosis could be made on the basis of examination of both smear and paraffin section. This procedure is particularly helpful in Hodgkin’s disease and reticulum cell sarcoma, where marrow smears are only rarely diagnostic.

In general, the patients in whom lesions were found in the bone marrow tended to have more advanced disease than those in whom lesions were not found, and abnormalities in the peripheral blood were more common. This was especially true of patients with Hodgkin’s disease, less so in those with reticulum cell sarcoma. Patients with lymphosarcoma, lymphocytic type, did not show this difference, either in the extent of the disease or in findings on examination of peripheral blood.

Diagnosis was most difficult in patients who had lymphocytic lymphosarcoma, since it was occasionally difficult to distinguish between the benign aggregations of lymphocytes which are not infrequently found in a large number of unrelated conditions and those aggregations which represented malignancy. Differentiation was made on the basis of number of aggregations, degree of circumscription, presence or absence of reaction centers and the cytologic appearance of the cells. Examination of the smears of the marrow is most helpful in these cases.

Seven patients in this series (9.7 per cent) had granulomatous lesions in the marrow. In five of these the final diagnosis was Hodgkin’s disease, in one reticulum cell sarcoma and in one follicular lymphoma. Although these lesions were not specific, the incidence is high enough to make the finding of a granuloma of some significance in any patient suspected of having malignant lymphoma.

The importance of thorough examination of any material obtained in an apparent dry tap and the value of repeated marrow-examinations is emphasized by three cases in this series.

Since in many cases diagnostic lesions are found in only one portion of the material, examination of only one section of the paraffin sections of aspirated bone marrow is not sufficient for proper evaluation. This fact is emphasized by the greater incidence of positive findings in this report than in that of Cooper and Watkins.

Studies of bone marrow should be particularly helpful in instances in which the diagnosis of malignant lymphoma is suggested by clinical features but cannot be proved by biopsy of peripheral nodes or other readily accessible tissue.