Nancy Senff, MD, Department of Dermatology, B1-Q, Leiden University Medical Center, PO Box 9600, 2300 RC Leiden, The Netherlands. E-mail: email@example.com
Whether or not bone marrow biopsies should be performed routinely in patients with skin lesions that show histological features consistent with an indolent B-cell lymphoma [marginal zone lymphoma (MZL) or follicle centre lymphoma (FCL)] has been debated. As no studies have addressed this question for this group of lymphomas, we evaluated the results of bone marrow biopsy examination in 275 patients with histological features consistent with MZL (n = 82) or FCL (n = 193) first presenting in the skin. In the MZL group, two of 82 patients (2%) showed bone marrow involvement, which was the only extracutaneous localization in one of these patients. In the FCL group, 22 of 193 patients (11%) had bone marrow involvement and was the only extracutaneous localization in nine of them. FCL patients with skin lesions and a positive bone marrow had a significantly worse prognosis when compared with patients with only skin lesions (5-year disease-specific survival 63% vs. 95%; P = 0·001). These results indicate that bone marrow investigation is essential for staging patients with a FCL first presenting in the skin. Bone marrow examination appears to have limited value in patients with MZL presenting in the skin.
Primary cutaneous lymphomas (PCLs) are defined as a group of non-Hodgkin lymphomas (NHLs) of either T-cell or B-cell origin that present in the skin without evidence of extracutaneous disease at the time of diagnosis. Distinction between PCL and systemic lymphomas that involve the skin secondarily is important because they often have a completely different clinical behaviour and prognosis, and may therefore require different types of treatment (Willemze et al, 2005).
A diagnosis of PCL can only be made after adequate staging investigations have been conducted. Adequate staging procedures include, in addition to a detailed history and physical examination, routine laboratory tests (complete and differential blood cell count and serum biochemistry), computed tomography (CT) scan of neck, chest and abdomen and a bone marrow biopsy. At recent consensus meetings of the European Organization for Research and Treatment of Cancer (EORTC) and the International Society of Cutaneous Lymphoma, which aimed to develop staging systems and guidelines for diagnosis and treatment of PCL other than mycosis fungoïdes and Sézary syndrome, the necessity to perform a bone marrow biopsy in indolent PCL was questioned. In the subsequent consensus paper (Kim et al, 2007), it was suggested that bone marrow examination was recommended, but not required in indolent PCL, including primary cutaneous anaplastic large cell lymphoma, primary cutaneous marginal zone lymphoma (PCMZL) and primary cutaneous follicle centre lymphoma (PCFCL), unless indicated by other staging assessments. Regarding the two types of indolent cutaneous B-cell lymphoma (CBCL), this is in accordance with the National Comprehensive Cancer Network clinical practice guidelines (v.1.2007; available at: http://www.nccn.org/professionals/physician_gls/PDF/nhl.pdf,. accessed 31 July 2007). These guidelines did not include bone marrow biopsies as part of the essential workup of follicular lymphoma and marginal zone lymphoma (MZL) and are only advised in selected cases. However, in most other guidelines, including those of the Dutch-Belgian Hemato-Oncology Group (available at : http://www.hovon.nl/hovon/stream.asp?hovnhl.pdf,. accessed 31 July 2007), unilateral trephine bone marrow biopsies are part of routine workup in all patients with (a suspicion of) non-Hodgkin lymphoma (Cheson et al, 1999, 2007).
The recommendation that a bone marrow biopsy is not required in indolent types of CBCL (PCMZL and PCFCL) is confusing, as studies describing these PCMZL and PCFCL as indolent lymphomas required negative staging procedures, including a negative bone marrow biopsy (Willemze et al, 2005). Henceforth, this recommendation means that a bone marrow is not required in patients who present with skin lesions that are clinically and histologically highly suggestive or consistent with a diagnosis of PCMZL or PCFCL, if other staging procedures are negative. In case of MZL, the consequences of not performing a bone marrow biopsy are expected to be limited. When staging (including a bone marrow biopsy) is negative, it identifies PCL, which – according to the World Health Organization (WHO)– EORTC classification for cutaneous lymphomas – is classified as PCMZL. If, however, a bone marrow biopsy and/or other staging procedures are positive, it does not identify PCL, and the WHO–EORTC classification should not be applied. Such cases should be classified according to the WHO classification as an extranodal marginal zone lymphoma with skin localizations. In both instances, it concerns an indolent type of B-cell NHL, and the therapeutic consequences will be minimal. In case of PCFCL, the situation is more complex. PCFCLs are defined as tumours of neoplastic follicle centre cells, usually a mixture of centrocytes and variable numbers of centroblasts, which may show a follicular (5%), follicular and diffuse (30%) or diffuse growth pattern (65%) (Senff et al, 2007). These PCFCLs are preferably treated with radiotherapy and have an excellent prognosis with a 5-year survival of 95%, irrespective of the growth pattern (follicular and/or diffuse) or the number of blast cells (Willemze et al, 2005). However, if a patient had clinicopathological features that suggested a PCFCL, and a bone marrow biopsy and/or other staging procedure was positive, a diagnosis of PCFCL could not be made. Such cases concern a secondary cutaneous lymphoma and should be classified according to the WHO classification as either follicular lymphoma or, in most cases, as a diffuse large B-cell lymphoma, which will have major therapeutic consequences. One would therefore assume that not performing a bone marrow biopsy in such cases may result in inappropriate treatment.
Studies on the frequency of extracutaneous manifestations, particularly a positive bone marrow biopsy, in patients presenting with skin lesions otherwise consistent with a PCMZL or PCFCL have never been performed. The present study therefore retrospectively evaluated the staging results of a large group of patients presenting with skin lesions that showed histological features consistent with a diagnosis of MZL or follicle centre lymphomas (FCLs). The aim was to evaluate the frequency of bone marrow involvement in these patients in order to determine whether our current policy to perform a bone marrow biopsy in all patients with a histological diagnosis of cutaneous MZL or FCL should be maintained or that it should only be performed in selected cases, as suggested recently (Kim et al, 2007).
Patients and methods
All patients who presented with skin lesions showing histological and immunophenotypical features consistent with a diagnosis of MZL (n = 107) or FCL (n = 250) between 1985 and 2006 were retrieved from the database of the Dutch Cutaneous Lymphoma Group. The term FCL is herein used for tumours of neoplastic follicle centre cells with either a follicular, a follicular and diffuse or a diffuse growth pattern, which should be classified as PCFCL if staging procedures were negative. All cases had been reviewed by a panel of haematopathologists and dermato(patho)logists and classified by consensus prior to entry in the database. For each patient in this registry, follow-up is collected yearly. Patients with a history of a prior systemic B-cell lymphoma (n = 16, two MZL and 14 FCL) and patients in whom a bone marrow biopsy was not performed (n = 66; 23 MZL and 43 FCL) were excluded from the study. The final study group consisted of 82 MZL and 193 FCL (Table I). Median follow-up for the whole group was 43 months (range 1–443 months). Staging procedures had included physical examination, complete and differential blood cell counts and serum biochemistry, CT scan of neck, chest and abdomen and a bone marrow biopsy. The results of the staging investigations were extracted from the patient’s files.
Table I. Selection of cases and results of bone marrow biopsy and DSS in marginal zone lymphomas and follicle center lymphomas first presenting in the skin.
Statistical calculations were performed using the statistical package for the social sciences (spss), version 14.0 (SPSS Inc., Chicago, IL, USA). Overall survival (OS) was calculated from the date of diagnosis until the patient’s death or date of last follow-up. Disease-specific survival (DSS) was calculated from the date of diagnosis until death from lymphoma (including therapy-related death) or censoring. Patients who were alive at last follow-up or patients who died of other causes were considered censored. Survival curves were estimated using the method of Kaplan and Meier and statistical comparison between curves was done by log-rank testing. P-values <0·05 were considered significant.
Marginal zone lymphoma
In the group of 82 MZL patients, 76 patients showed no signs of extracutaneous involvement during staging investigations and were diagnosed as PCMZL (Table I) (Willemze et al, 2005). In six cases (7%), extracutaneous localizations were found, including five patients with enlarged lymph nodes on a CT scan. Bone marrow involvement was found in two of these six patients, in one of them as part of widespread disease with involvement of central lymph nodes and peripheral blood, and in the other patient as the only evidence of extracutaneous disease. The first patient was treated with chemotherapy, but died from secondary acute myeloid leukaemia 3 years after diagnosis. The second patient has been in complete remission for over 5 years following an autologous bone marrow transplantation and radiotherapy for a skin relapse during follow-up. Patients with and without extracutaneous involvement had a 5-year OS of 33% and 91%, respectively, and a 5-year DSS of 50% and 98% respectively (Table I).
Follicle centre lymphoma
Of 193 FCL patients with complete staging workup, 157 patients showed no evidence of extracutaneous disease and were classified as PCFCL (Willemze et al, 2005). Extracutaneous disease was detected at the time of diagnosis in 36 cases (19%). Nine of 36 cases showed the characteristics of a follicular lymphoma, while the other 28 cases lacked a follicular component and were classified as diffuse large B-cell lymphoma. Taken together, in 22 of these 36 cases, the bone marrow biopsy was positive or contained lymphoid aggregates that were highly suspicious for lymphoma involvement (Table I). Bone marrow involvement was accompanied by more extensive involvement of other organs or lymph nodes in 13 patients, as assessed by CT scans and/or lymph node histology. In the remaining nine cases, the bone marrow was the only extracutaneous localization. The 14 patients with extracutaneous disease but no bone marrow involvement showed nodal disease as assessed by CT scan and/or lymph node biopsy (n = 13), while one patient showed bone involvement.
The 5-year OS for the 36 patients with and the 157 patients without extracutaneous involvement was 42% and 84%, respectively, whereas the 5-year DSS was 52% and 95% respectively (P < 0·001; Fig 1). Patients with bone marrow involvement with or without extracutaneous localizations at other sites had a 5-year OS of 30% and 44% and a 5-year DSS of 30% and 63% respectively (Table I).
Whether or not bone marrow biopsies should be routinely performed in patients with an MZL or FCL first presenting in the skin (Kim et al, 2007) has been recently debated. As there are, to the best of our knowledge, no studies that have addressed this question for this particular group of lymphomas, we evaluated the results of bone marrow biopsy examinations in 275 patients with an MZL or FCL first presenting in the skin. Considering the whole group of 275 patients, 24 patients (9%) had bone marrow involvement at initial diagnosis, while this was the only evidence of extracutaneous disease in 10 patients (4%).
In the MZL group, only two of 82 (2%) patients had bone marrow involvement, which was the only evidence of extracutaneous disease in one of them. Thus, if bone marrow biopsies had not been performed in this group, only one of 82 cases would have been misdiagnosed as PCMZL.
Recent studies on large cohorts of non-gastric extranodal marginal zone B-cell lymphoma of mucosa-associated lymphoid tissue (MALT lymphoma) report bone marrow involvement at initial diagnosis in 14–28% of patients (Zinzani et al, 1999; Zucca et al, 2003; Arcaini et al, 2006). Cutaneous MZL included in these studies showed bone marrow involvement in zero of seven (Zinzani et al, 1999) and two of 22 (9%) (Zucca et al, 2003) cases respectively. As a considerable proportion of MALT lymphomas present with disseminated disease, these studies emphasize the need for extensive staging procedures, including a bone marrow biopsy. In addition, these studies associated bone marrow involvement with an inferior prognosis. In contrast, a recent Austrian study found bone marrow involvement in only three of 140 (2%) MALT lymphomas, including one of 79 (1%) non-gastric MALT lymphomas, thus arguing against the necessity of a routine bone marrow biopsy (Raderer et al, 2006). The different frequencies of bone marrow involvement in these studies are as yet unexplained.
The results of the present study and data from the literature indicate that bone marrow involvement is uncommon in MZL first presenting in the skin, and that it is rarely the only manifestation of extracutaneous disease. Moreover, treatment of MZL with skin lesions and isolated bone marrow involvement will not be different from that of MZL presenting with only skin lesions (PCMZL). In both cases, radiotherapy will be the primary option, although the (known) presence of bone marrow involvement will ask for a closer follow-up of such a patient compared with a patient with only skin involvement. It is also interesting to note that the 23 patients with cutaneous MZL in whom no bone marrow biopsy was performed, and who were excluded from the present study, had a 5-year DSS of 100% (see Table I). Thus, from a clinical point of view, there does not seem to be a good reason to consider a bone marrow biopsy mandatory in these patients. However, if bone marrow biopsies are no longer performed, a definite diagnosis of PCMZL can no longer be made with certainty. Given the major pathogenetic differences in terms of translocations and antigenic stimuli involved in the development of MALT lymphomas at different sites (Cohen et al, 2006; Ferreri & Zucca, 2007; Inagaki, 2007), not performing a bone marrow biopsy may obscure the distinction between primary and secondary cutaneous cases and hamper elucidation of the pathogenesis of genuine PCMZL.
In the group of FCL first presenting in the skin, bone marrow was involved in 22 of 193 cases (11%), whereas bone marrow involvement was the only evidence of extracutaneous disease in nine of them. Thus, if bone marrow biopsies had not been performed in this group, nine cases would have been incorrectly classified as PCFCL. The finding of bone marrow involvement in these nine patients appears clinically relevant, as they had a significantly worse survival as compared with the 157 PCFCL patients (5-year OS 44% vs. 84%; P = 0·001; 5-year DSS 63% vs. 95%; P = 0·001; see Fig 2). In addition, although the clinical presentation (site and extent of skin lesions) in these nine patients did not differ from patients with a PCFCL, the presence of bone marrow involvement may also have therapeutic consequences.
In three of nine cases, the skin infiltrates showed a partial follicular growth pattern and were classified as follicular lymphoma with skin and bone marrow involvement. In the other six cases, the skin biopsies showed a diffuse population of large cleaved cells without a follicular component and were classified as diffuse large B-cell lymphoma according to the WHO classification. Taken together, these data indicate that a bone marrow biopsy is mandatory in patients with an FCL first presenting in the skin.
Due to the fact that these patients were collected during a 20-year period, all data were retrieved from a database or patient’s files, and some of these could not be reviewed. The quality of CT scans has very much improved, and positron emission tomography scans have recently contributed to the upgrading of staging procedures. As far as bone marrow biopsies are concerned, much has changed during the last decade. The guidelines published by Cheson et al (1999) require a well-defined quality, regarding length of the specimen (>2 cm) with sufficient marrow fields, and in the case of doubtful infiltration additional immunohistochemistry, which obviously was not available in the early years of this study. Although some false-positive marrows might have been present, one would rather expect false-negative bone marrows. We therefore believe that there are two reasons why the percentage of positive bone marrow biopsies might be even higher than found in our study. First, in the absence of a histological review of the bone marrow biopsies, it could not be excluded that some cases designated as negative were in fact of insufficient quality to allow a definite conclusion. Exclusion of such ‘false-negative’ bone marrow biopsies would result in a higher percentage of positive bone marrow examinations. Second, one of the main goals of the Dutch Cutaneous Lymphoma Group is to assist referring dermatologists and pathologists in making a correct diagnosis of patients with (suspicion of) a cutaneous lymphoma. Although the database contains both primary and secondary cutaneous lymphomas, patients presenting with skin lesions and extensive extracutaneous disease, and who were primarily referred to a haematologist, may not have been included in the Dutch Cutaneous Lymphoma Group database. If such patients had been included, the percentage of positive bone marrow biopsies would definitely have been higher. However, we believe that this would apply to only a few patients as compared with the large number of cases included in this study, and therefore would not significantly influence our conclusions.
In conclusion, the results of this study indicate that bone marrow investigation is an essential component of staging procedures in patients with an FCL first presenting in the skin. From a clinical point of view, bone marrow examination appears to have limited value in patients with MZL presenting in the skin, and may be considered only in selected cases, as previously suggested (Kim et al, 2007).