A unique case of mantle cell lymphoma with an aberrant [CD5.sup.-]/[CD10.sup.+] immunophenotype and typical morphology.
Abstract: Mantle cell lymphoma (MCL) is a non-Hodgkin lymphoma with a poor prognosis that may be confused with less aggressive diseases, such as small lymphocytic lymphoma and follicular lymphoma. In many cases immunophenotyping, particularly analysis of reactivity for CD5 and CD10, is an important adjunct to morphology that usually distinguishes MCL from follicular lymphoma; the former is [CD5.sup.+]/[CD10.sup.-], whereas follicular lymphoma is the reverse. We report a case of MCL, initially diagnosed as follicular lymphoma, that at presentation expressed neither CD5 nor CD10. At relapse, it was still [CD5.sup.-], but CD10 was now detected. Studies for a t(11;14) translocation and CYCLIN D1 protein expression, however, permitted a revised diagnosis of MCL. An MCL with this immunophenotype and classical morphology has not been previously reported.
Article Type: Disease/Disorder overview
Subject: Phenotype (Identification and classification)
Immunopathology (Research)
Mantle cell lymphoma (Development and progression)
Mantle cell lymphoma (Care and treatment)
Morphology (Research)
Authors: Sriganeshan, Vathany
Blom, Thomas R.
Weissmann, David J.
Pub Date: 08/01/2008
Publication: Name: Archives of Pathology & Laboratory Medicine Publisher: College of American Pathologists Audience: Academic; Professional Format: Magazine/Journal Subject: Health Copyright: COPYRIGHT 2008 College of American Pathologists ISSN: 1543-2165
Issue: Date: August, 2008 Source Volume: 132 Source Issue: 8
Topic: Event Code: 310 Science & research
Geographic: Geographic Scope: United States Geographic Code: 1USA United States
Accession Number: 230246797
Full Text: Mantle cell lymphoma (MCL) is a moderately aggressive B-cell non-Hodgkin lymphoma (NHL) that was first distinguished in the 1990s from morphologically similar lymphomas, such as small lymphocytic lymphoma (SLL) and follicular lymphoma (FL). Its characteristic immunophenotype includes coexpression of B-cell markers, CD5, and FMC-7 and absence of CD23, whereas the translocation t(11;14)(q13;q32) confirms the diagnosis. Occupying the middle ground between low- and high-grade lymphomas, MCL permits neither a long survival, like SLL and FL, nor a cure with aggressive chemotherapy, like large cell lymphoma. Thus, it has a poor overall and failure-free survival rate, in contrast to the good survival anticipated with most low-grade B-cell lymphoma subtypes. No current therapy is curative.

It is particularly important to distinguish MCL from SLL and FL, all of which are composed of small cells with clumped chromatin and scant cytoplasm. Cytomorphology and low-power architecture can differentiate the 3 lymphomas on many occasions, but most pathologists will immunophenotype a suspected MCL. Although both MCL and SLL are positive for CD5, MCL also expresses FMC-7 but not CD23, and bright (as opposed to dim) CD20 and surface immunoglobulin. Mantle cell lymphoma is also negative for CD10 which, along with CD5 positivity, distinguishes it from FL. (1)

The strongest confirmation of a suspected MCL is identification of t(11;14) by cytogenetic or fluorescent in situ hybridation (FISH) techniques, but these studies are not always performed, and immunophenotyping is the most useful adjuvant to morphology. It is important to recognize, however, that there are exceptions to the [CD5.sup.+]/ [CD10.sup.-] immunoprofile of most MCLs. Various combinations of positivity and negativity for these markers have been described in the literature, but to our knowledge there has never been a report of [CD5.sup.-] MCL with classic morphology that converted from [CD10.sup.-] to [CD10.sup.+] without progression to the blastoid variant. We herein report such a case with proven cyclin D1 positivity and review the literature about the expression of these markers in MCL and their implications for diagnosis.


A 71-year-old woman presented to our institution with a swelling on the left side of her neck. Her stated history of follicular lymphoma was based on a biopsy of a left supraclavicular lymph node performed at an outside institution 4 years prior to this admission. The presumptive low-grade lymphoma prior to the diagnosis of mantle cell lymphoma was treated intermittently with chlorambucil when her nodes in the cervical chain became symptomatic. More aggressive treatment was not attempted because of the indolent pattern of her disease and a poor performance status from pelvic abscesses, intermittent small bowel obstruction, and associated surgical procedures.

At the time of the second and current biopsy, physical examination revealed a left neck mass measuring 4 X 6 cm that was clinically suspicious for recurrent lymphoma. An excisional biopsy revealed a lymph node with complete effacement of architecture by a predominantly diffuse infiltrate with focal nodularity, composed of small cells with irregular nuclei (Figure 1, A and B). Scattered epithelioid histiocytes created a "starry sky" pattern.

By cytofluorimetric analysis, these cells were positive for CD19, CD20, CD10, and monoclonal [lambda] light-chain expression but were negative for CD5. By immunohistochemistry, they were positive for CD79a, PAX-5, CD10 (Figure 2, B), Bcl-2, and cyclin D1 (Figure 2, C), and were weakly positive for Bcl-6 and MUM-1 but negative for CD5 (Figure 2, A). Staining for Ki-67 showed a high proliferation index of 50%.

A diagnosis of MCL with an unusual immunophenotype was considered, based on the morphology and positive nuclear staining with cyclin D1. A FISH study was positive for t(11;14) involving CCND1 and IgH genes in 112 of 200 interphase cells examined. Additional FISH studies were negative for t(14;18) and any c-myc rearrangement.

A review of slides from the prior, original supraclavicular lymph node biopsy revealed architectural effacement by a nodular infiltrate composed predominantly of small lymphocytes with slightly irregular nuclei, without any admixture of larger cells (Figure 3, A and B). Flow cytometry had been reported to show a B-cell population with X light-chain restriction that was positive for CD19 and CD20 but negative for CD5, CD10, and CD23. Despite the negativity for CD10, the morphology was deemed suggestive of a low-grade follicular lymphoma. Although immunohistochemistry was not done at the time of biopsy, retrospective analysis at our institution showed that the cells were positive for cyclin D1 (Figure 4, C) and confirmed their negativity for CD5 (Figure 4, A) and CD10 (Figure 4, B).


Immunohistochemical Analysis

Immunohistochemical analysis was performed on paraffin sections of formalin-fixed, paraffin-embedded tissue with the following antibodies: CD79a, CD10, BCL-2, and Ki-67 (prediluted, Ventana, Tucson, Ariz), PAX-5 and BCL-6 (Cell Marque, Rocklin, Calif), cyclin D1 (NeoMarkers, Fremont, Calif), and MUM1 (1:25; Vector, Burlingame, Calif). Appropriate positive and negative controls were used. All slides were stained on a Ventana Medical Systems Benchmark automated immunohistochemistry system.

Flow Cytometry Analysis

Four-color flow cytometric analysis was performed with manually dispersed fresh cell suspensions. A direct antibody labeling technique was used for mouse monoclonal antibodies (CD45, CD2, CD3, CD4, CD8, CD5, CD7, CD10, CD19, CD20, CD2, CD23, FMC-7, [kappa], and [lambda]) conjugated to fluorescein isothiocyanate, phycoerythrin, phycocyanin 5, and energy-coupled dye. The antibody cocktails were prepared by Beckman Coulter (Hileah, Fla). Data acquisition was performed on a Cytomics FC500 flow cytometer (Beckman Coulter), and the data were analyzed with CXP software (Beckman Coulter). The level of antigen expression was visualized by dual histograms.

Fluorescence In Situ Hybridization

Locus-specific interphase FISH analysis was performed on 4-[micro]m sections of paraffin-embedded tissue according to the manufacturer's suggested protocol (Vysis Inc, Downers Grove, Ill). For detection of t(11;14)(q13;q32), commercially available LSI IGH/CCND1 dual-color, dual-fusion probes were used. Additional analysis for t(14;18) using IGH/BCL2 and MYC/IGH, both dual-color, dual-fusion probes, was performed. All of the probes were prepared by Vysis Inc. Positive fusion signals in more than 2% of 200 nuclei examined are reported as positive. Hybridization was done according to the manufacturer's suggested protocol (Vysis). Dual-color, dual-fusion probes were used for the following translocations: t(11;14) with the LSI IGH/CCND1 probes, t(14;18) with IGH/BCL2 probes, and c-myc rearrangements with MYC/IGH probes (Vysis). Positive fusion signals in more than 2% of 200 nuclei examined are reported as positive.


Mantle cell lymphoma is an aggressive lymphoma with morphology that may cause confusion with lower-grade diseases, such as SLL or FL. It has previously been referred to by many different names, including centrocytic lymphoma, intermediate lymphocytic lymphoma, and mantle zone lymphoma. It usually presents in elderly patients with advanced stage disease. Involvement of peripheral blood and extranodal sites, including the spleen, liver, and gastrointestinal tract (termed lymphomatous polyposis)is common.

Mantle cell lymphoma infiltrates lymph nodes in a diffuse, nodular or, rarely, mantle zone pattern. Its classic histology shows a monotonous population of small to medium-sized lymphocytes with very little cytoplasm and cleaved nuclei and rare or no admixed larger cells. The more aggressive blastoid variant comprises a spectrum of forms, including large, lymphoblastoid, or pleomorphic cells. This blastoid variant has been interpreted as a de novo lymphoma and not a histologic progression from the classic form, (1) although other authors do report cases of progression. (2)

The gold standard for the diagnosis of suspected MCL is identification of the t(11;14)(q13;q32) translocation, which places the cyclin D1 (CCND1) gene from chromosome 11 under the control of the immunoglobulin heavychain gene promoter on chromosome 14, resulting in overexpression of the proliferation protein, cyclin D1 (also called Bcl-1). (3) Routine karyotyping detects the translocation in only 65% of cases, but FISH is successful in virtually all instances. (3) Immunohistochemistry can also detect the upregulated protein product, cyclin D1, which deregulates the normal cell cycle at the [G.sub.1]-S phase.

Mantle cell lymphomas are believed to be derived from a subset of naive, [CD5.sup.+] pregerminal center cells in the primary follicle or in the mantle zone region of secondary follicles. (1,4) As such, they are usually negative for germinal center markers, like CD10 and Bcl-6, and lack somatic mutation of the immunoglobulin gene. Recent molecular studies, however, have shown the variable region of the heavy chain ([V.sub.H]) of the immunoglobulin molecule (IGHV) mutation in up to 20% to 60% of cases. (4,5) Some studies suggest that there is no difference in prognosis between the mutated and unmutated phenotype, (4) whereas others contend that the mutated phenotype conveys a more favorable prognosis, similar to CLL. (5)

CD5-negative cases of MCL, with the usual morphology and clinical behavior, have been reported in the literature, with an incidence of about 11%. (6) Such lymphomas presumably have genetic alterations that bypass the advantages conferred by CD5 expression, which upregulates interleukin 10 expression and represses signals from the B-cell receptor that may foster cell death. (7) B-cell lymphomas that coexpress CD5 and CD10 are much more uncommon (0.4% of B-cell lymphomas), and only 20% of these are MCLs. (8) Most rare of all is the possibility of a [CD5.sup.-]/ [CD10.sup.+] MCL. Morice et al (9) reported a single instance of leukemic MCL comprising both a typical component with the usual morphology and immunophenotype and a blastoid variant that was [CD5.sup.-]/[CD10.sup.+].

We report an unusual case of MCL presenting initially with a morphology suggestive of a follicular lymphoma and a [CD5.sup.-]/[CD10.sup.-] immunophenotype. At relapse, the CD5 was still negative, but CD10 was positive by cytofluorimetric analysis as well as by immunohistochemistry. The classic t(11;14) translocation was confirmed both by FISH and immunohistochemistry for cyclin D1. Cyclin D1 staining was also positive when performed retrospectively on the initial specimen. In the recurrent specimen, the cy tomorphology was unchanged, although the architecture had become more diffuse. This sequence of events and departure from the typical immunophenotype are unique in the literature.


Additional paraffin immunostaining revealed more departures from the usual MCL immunoprofile. MUM1 (also known as IRF4) is a myeloma-associated oncogene that may be activated as a result of the translocation t(6;14). It has recently been shown to be expressed in B-cell non-Hodgkin lymphomas of germinal center or post-germinal center origin--including many cases of diffuse large B-cell lymphoma, marginal zone lymphoma, and small lymphocytic lymphoma--but not in mantle cell lymphoma. (10) Staining for MUM1 in our case, however, was positive.

Our case was also positive for Bcl-6. Initially, Bcl-6 mutations and expression were not seen in MCL. (11) Subsequently, Camacho et al (12) reported 5 cases of Bcl-[6.sup.+] MCL: one case with an extra copy of the BCL6 gene, and the others with a translocation involving 3q27. Two cases were negative for CD5, one was positive for CD10, and 1 of 3 cases showed somatic mutation of the IGHV gene. All cases tended to show a slightly increased proliferation index, as measured by Ki-67 staining. In our case, although the diagnosis of mantle cell lymphoma seems secure based on the morphology and the t(11;14) translocation, the positivity for Bcl-6 and CD10 is reminiscent of germinal center origin. We were not able to establish the mutational status of the IGHV gene.

The fact that our case was originally diagnosed as FL illustrates that diagnosing MCL is not always straightforward, despite its multiple distinguishing characteristics. Both morphology and the cytofluorimetric immunoprofile may be misleading. Cytogenetic or FISH studies for the t(11;14) translocation or an immunohistochemical study for cyclin D1 expression should be performed in any case that arouses suspicion, and a low index of suspicion may be necessary. Gene expression profiling is another technique for securing the diagnosis, but this technique is not in routine clinical use. (13) Such profiling has even raised the specter of a true cyclin D1-negative MCL, (14) violating the putative gold standard and contradicting earlier studies that required positivity for the diagnosis. (15)

Ultimately, awareness of the heterogeneity of this lymphoma and a multimodality approach with integration of clinical features, morphology, phenotype, and genetic and molecular findings may be required to accurately diagnose some cases of MCL. In our case, the technique that might have permitted an initial correct diagnosis is the oldest: morphologic recognition that the absence of any larger cells in a homogeneous population of small cells with clumped chromatin and irregular nuclei should exclude both FL and SLL.


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(13.) Rosenwald A, Wright G, Wiestner A, et al. The proliferation gene expression signature is a quantitative integrator of oncogenic events that predicts survival in mantle cell lymphoma. Cancer Cell. 2003;3:185-197.

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(15.) Yatabe Y, Suzuki R, Tobinai K, et al. Significance of cyclin D1 overexpression for the diagnosis of mantle cell lymphoma: a clinicopathologic comparison of cyclin D1-positive MCL and cyclin D1-negative MCL-like B-cell lymphoma. Blood. 2000;95:2253-2261.

Vathany Sriganeshan, MD; Thomas R. Blom, MD; David J. Weissmann, MD

Accepted for publication January 8, 2008.

From the Department of Pathology and Laboratory Medicine, Mount Sinai Medical Center, Miami Beach, Fla (Dr Sriganeshan); and the Division of Hematology-Oncology, Department of Medicine, Robert Wood Johnson Medical School and Cancer Institute of New Jersey, and the Division of Hematopathology, Department of Pathology and Laboratory Medicine, Robert Wood Johnson Medical School, New Brunswick, NJ (Drs Blom and Weissmann).

The authors have no relevant financial interest in the products or companies described in this article.

Reprints: Vathany Sriganeshan, MD, Department of Pathology and Laboratory Medicine, Mount Sinai Medical Center, Blum Building, Room 2400, 4300 Alton Rd, Miami Beach, FL 33140 (e-mail: vsrigane@msmc.com).
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