Guidelines for subtyping small B-cell lymphomas in bone marrow biopsies

Abstract

In this review, we summarise the patterns of bone marrow involvement by small B-cell lymphomas. Both our own experience and the literature reports on the subject show that each subtype of lymphoma can be recognised from a distinct combination of a suggestive growth pattern and a particular cytological composition. A predominantly paratrabecular infiltrate composed of centrocytes is characteristic of follicle centre cell lymphoma. In mantle cell lymphoma, prominent intertrabecular nodules, each consisting of a monotonous proliferation of small to intermediate-sized lymphoid cells with an irregular nucleus, are the most frequent finding. Marginal zone cell lymphoma displays similar intertrabecular nodules, but the infiltrates are rather loose and polymorphic, whereas the lymphoid cells exhibit monocytoid features. Diffuse infiltrates composed of small lymphocytes with clumped chromatin, of plasma cells with Dutcher bodies and of mast cells are observed in most cases of lymphoplasmacytoid lymphoma/immunocytoma. Although chronic lymphocytic leukaemia / small lymphocytic lymphoma can present with a comparable pattern of bone marrow involvement, an interstitial infiltrate of small lymphoid cells is usually observed. A comparable interstitial pattern also prevails in hairy cell leukaemia. This lymphoma subtype, however, can be readily identified by the abundant clear cytoplasm of the neoplastic cells, erythrocyte extravasation and associated abnormalities in the haematopoietic series.

Nódulos linfóides medulares

“…15,19,20,21 Ocasionalmente alguns marcadores adicionais podem ser necessários, como anticorpos contra cadeias leves de Ig nas proliferações plasmocitóides, CD5 ou ainda ciclina D1 para o diagnóstico de linfoma de células do manto ou de pequenas células B. West e colaboradores demonstraram que um painel composto por CD20, CD5, CD10 e bcl-2 é útil para a distinção entre agregados linfóides medulares benignos e neoplásicos 22 (Tabela 3).…”

“…10 Nos linfomas de curso indolente, o envolvimento da medula óssea pode ser observado num percentual significativo de casos, alcançando em algumas séries 90%. 13,14,15 O linfoma folicular representa o tipo que mais freqüen-temente invade a medula óssea. Pequenos infiltrados, no entanto, são potencialmente obscurecidos por outras células medulares e podem passar despercebidos.…”

Diagnosis and Classification of Malignant Lymphoma and Related Entities in the Bone Marrow Trephine Biopsy

“…BM infiltration by malignant lymphoma is not a random process but is influenced by characteristics of the neoplastic cells as well as microenvironmetal features, leading to a characteristic pattern of marrow involvement for many lymphoma subtypes [4,6,7,13] . These infiltration patterns, though not absolutely specific, may provide diagnostic clues both for the discrimination of benign and malignant infiltrates as well as for NHL subtyping.…”

“…In lymphoma patients, the trephine biopsy renders important diagnostic information which cannot be obtained from BM aspirates, namely on architectural features of the infiltrate and its topographic distribution as well as the amount of marrow space occupied by a malignant infiltrate [4,6,7] . Furthermore, assessment of marrow involvement by histology is not impeded by fibrosis, which is a frequent finding in lymphomatous infiltrates and may lead to false-negative results in BM aspirates due to sampling error [8][9][10] .…”

“…The development of a broad range of antibodies suitable for paraffin-embedded tissues, in conjunction with decalcification techniques, which are non-detrimental for most relevant antigens, has increased the diagnostic value of the BM biopsy further and has made it complementary, and in many instances superior to flow cytometric immunophenotyping of BM aspirates [6,7,13] . The present review gives an overview of the practical issues in the diagnostic evaluation of BM trephines in patients with malignant lymphoma and related disorders and critically reviews the role of ancillary techniques.…”