Classification of cutaneous lymphomas: crosstalk between pathologist and clinician

[The history of lymphoma classifications with special consideration of cutaneous lymphomas]

For modern evidence-based medicine, classification systems are necessary to guarantee a uniform approach for therapy and for estimating prognosis. The comparability of clinical studies and international communication require a common language and are only possible with modern international classification systems. But because all classifications are artificial, they only mirror the current state of knowledge and may change dramatically over decades. This review discusses the history of lymphoma classifications systems with a special focus on the topic of primary cutaneous lymphomas, emphasizing special problems in terminology.

Cutaneous extranasal NK/T-cell lymphoma

Malignant neoplasm from natural killer (NK) cells are characterized by their positivity for CD56 and absence of monoclonal TCR gene rearrangement. We present the case of a 54-year-old man with a fungous mass in his left flank whose histological examination was consistent with cutaneous extranasal T/NK cell lymphoma. We review the literature and also discuss the prognosis and treatment of this variety of lymphoma.

Modern diagnosis of cutaneous lymphoma

The issue of primary cutaneous lymphoma (CL) has been greatly influenced by the increasing knowledge about lymphoid cell biology, the widespread use of sensitive and specific immunological and molecular markers, and the careful correlation among clinical, histological and immunomolecular features. This latter is the key element of the classification of CL proposed by the EORTC Cutaneous Lymphoma Study Group in 1997, which categorizes distinct clinicopathological entities with prognostic and therapeutic relevance. With few exceptions, no reliable diagnosis and subtyping of CL can be made without the aid of immunohistochemistry and/or molecular analysis. On the other hand, the acritical use of immunological and molecular markers can be misleading if not combined properly with a correct clinical and histological evaluation. For this reason, a step-by-step diagnosis and staging protocol is exceedingly important. Finally, great caution should be used in the interpretation of lymphoid cell infiltrates of the skin which show a monoclonal rearrangement in the absence of reliable clinical and/or pathological evidence of neoplasia.

Phase II trial of interferon-alpha-2a plus psolaren with ultraviolet light A in patients with cutaneous T-cell lymphoma

PURPOSE

To evaluate the efficacy and side effects of psolaren with ultraviolet light A (PUVA) and interferon-alpha-2a (IFN-alpha-2a) in patients with mycosis fungoides (MF) and Sézary syndrome (SS).

PATIENTS AND METHODS

From May 1993 to January 1999, 63 symptomatic patients with all stages of MF and SS were treated in a prospective Phase II trial with systemic escalating doses of IFN-alpha-2a combined with PUVA for 1 year, followed by indefinite PUVA maintenance in complete responding patients.

RESULTS

Sixty-three patients were enrolled (Stage IA, n = 6; IB, n = 37; IIA, n = 3; IIB, n = 3; III, n = 12; IVA, n = 2). Ten patients had received previous therapy. The median follow-up duration for the entire cohort is 37 months. Of 63 patients, 51 achieved a complete response (CR; 74.6%) or partial response (PR; 6%) to therapy. The median response duration is 32 months. The 5-year overall survival rate is 91% and the 5-year disease-free survival rate is 75%. No life-threatening side effects were observed. Five patients stopped IFN-alpha-2a therapy due to toxicity. Eighty-four percent of the patients received more than 75% of the planned dose (12 million units three times a week).

CONCLUSIONS

This combination of IFN-alpha-2a and phototherapy is an effective and safe therapy for patients with symptomatic MF.

Primary CD30-positive cutaneous T-cell lymphomas and lymphomatoid papulosis frequently express cytotoxic proteins

AIMS

To analyse the relationship between expression of cytotoxic proteins, histopathology and the CD30 status in primary cutaneous T-cell disorders, we investigated the expression of TIA-1, granzyme B and perforin in CD30 negative and CD30 positive cutaneous T-cell lymphomas (CTCL) and lymphomatoid papulosis (LP).

METHODS AND RESULTS

We studied 26 cases of CTCL and 12 cases of LP for the expression of TIA-1, granzyme B and perforin which are granule-associated proteins of cytotoxic lymphocytes involved in the mechanism of apoptosis. We showed that most cases (10/13) of CD30 negative pleomorphic lymphomas expressed cytotoxic proteins only in scattered, apparently reactive lymphocytes, the exception being one CD8+ CTCL and two gammadelta subcutaneous 'panniculitis-like' T-cell lymphomas. We also showed that at least one cytotoxic protein was expressed in a proportion of neoplastic cells in 77% (10/13) of CD30+ T-cell lymphomas (3/4 pleomorphic and 7/9 anaplastic) and in a proportion of atypical cells in 75% (9/12) of LP.

CONCLUSIONS

Our findings show a strong correlation between the CD30 phenotype and the expression of cytotoxic proteins in primary CTCL. In addition, these results provide further evidence for an overlap between lymphomatoid papulosis and cutaneous CD30+ pleomorphic and anaplastic lymphomas. These entities, which belong to the spectrum of CD30 positive cutaneous T-cell lymphoproliferations, appear to be derived from cytotoxic cells.

Morphologic spectrum of cutaneous B-cell lymphomas

Cutaneous B-cell lymphomas represent a heterogeneous group of entities which show variation in histology, immunophenotype, and in prognosis. In the current review the morphologic spectrum of cutaneous B-cell lymphomas comprising primary and secondary cutaneous B-cell lymphomas is discussed according to the REAL classification scheme.

EORTC classification for primary cutaneous lymphomas: the best guide to good clinical management. European Organization for Research and Treatment of Cancer

In 1997 the Cutaneous Lymphoma Study Group of the European Organization for Research and Treatment of Cancer (EORTC) published a proposal for a classification for the group of primary cutaneous lymphomas (1). The EORTC classification is the first and only classification that is designed exclusively for the group of primary cutaneous lymphomas. It is also the only classification that has been clinically validated for this group of diseases. As illustrated by this special issue, this classification has resulted not only in the discussion of the definition and terminology of some types of cutaneous T-cell lymphoma (CTCL) and cutaneous B-cell lymphoma (CBCL), but also in a discussion of whether organ-based classification schemes (separate from existing hematopathologic classification schemes for non-Hodgkin lymphomas) should be used. This article explains why it was necessary to create a separate classification for the group of primary cutaneous lymphomas. A short introduction on the history of the classification of cutaneous lymphomas is provided. Next, the basic principles of the EORTC classification are presented. Finally, controversies between the EORTC classification versus the REAL classification (2) and the proposed WHO classification (3), which still impede the usage of one common classification system, are discussed.