CD30-rich transformed mycosis fungoides or anaplastic large cell lymphoma? How to get it right

Differential molecular programs of cutaneous anaplastic large cell lymphoma and CD30-positive transformed mycosis fungoides

Background

Discriminating between cutaneous anaplastic large cell lymphoma (cALCL) and CD30-positive transformed mycosis fungoides (CD30+ TMF) is challenging, particularly when they arise in the context of pre-existing mycosis fungoides. The development of molecular diagnostic tools was hampered by the rarity of both diseases and the limited understanding of their pathogenesis.

Methods

In this study, we established a cohort comprising 25 cALCL cases and 25 CD30+ TMF cases, with transcriptomic data obtained from 31 samples. We compared the clinicopathological information and investigated the gene expression profiling between these two entities. Furthermore, we developed an immunohistochemistry (IHC) algorithm to differentiate these two entities clinically.

Results

Our investigation revealed distinct clinicopathological features and unique gene expression programs associated with cALCL and CD30+ TMF. cALCL and CD30+ TMF displayed marked differences in gene expression patterns. Notably, CD30+ TMF demonstrated enrichment of T cell receptor signaling pathways and an exhausted T cell phenotype, accompanied by infiltration of B cells, dendritic cells, and neurons. In contrast, cALCL cells expressed high levels of HLA class II genes, polarized towards a Th17 phenotype, and exhibited neutrophil infiltration. An IHC algorithm with BATF3 and TCF7 staining emerged as potential diagnostic markers for identifying these two entities.

Conclusions

Our findings provide valuable insights into the differential molecular signatures associated with cALCL and CD30+ TMF, which contribute to their distinct clinicopathological behaviors. An appropriate IHC algorithm could be used as a potential diagnostic tool.

CD30-positive lymphoproliferative disorders-An Australian Clinical Practice Statement from the Peter MacCallum Cancer Centre

The CD30-postive lymphoproliferative disorders, including lymphomatoid papulosis and primary cutaneous anaplastic large cell lymphoma, account for up to 30% of all cutaneous T-cell lymphomas (CTCLs) and are the second most common form of CTCLs after mycosis fungoides. Both conditions differ in their clinical presentations; however, they share the expression of the CD30 antigen as a common immunophenotypic hallmark. There is a wide spectrum of management options depending on factors such as extent of disease, staging and treatment tolerability. This Clinical Practice Statement is reflective of the current clinical practice in Australia.

CD30+ Lymphoproliferative Disorders as Potential Candidates for CD30-Targeted Therapies

CONTEXT.—

In the early 1980s, a monoclonal antibody termed Ki-1 was developed against a cell line derived from a patient with Hodgkin lymphoma. This antibody detected a limited number of benign activated lymphocytes in lymphoid tissue, whereas in Hodgkin lymphoma it appeared to be nearly specific for Reed-Sternberg cells and their mononuclear variants. Subsequent studies showed that Ki-1 expression defined a new type of lymphoma that was later designated anaplastic large cell lymphoma with or without anaplastic large cell kinase expression/translocation. In the past 30 years, numerous new lymphoma entities have been defined, many of which are variably positive for CD30. Many virally transformed lymphoproliferative disorders are also frequently positive for CD30.

OBJECTIVE.—

To illustrate the broad spectrum of CD30+ hematologic malignancies and to provide an update of CD30-targeted therapies.

DATA SOURCES.—

Personal experiences and published works in PubMed.

CONCLUSIONS.—

Because of its low expression in normal tissue, CD30 was studied as a therapeutic target for many years. However, the first functional humanized antibody against CD30 was developed only about 10 years ago. Brentuximab vedotin is a humanized anti-CD30 antibody linked to a cytotoxin, and was approved by the US Food and Drug Administration in 2012 for treating refractory Hodgkin lymphoma and anaplastic large cell lymphoma. Since then, the list of Food and Drug Administration-approved CD30-targeted hematologic malignancies has grown. Recently, the therapies using tumor antigen-specific chimeric antigen receptor T cells targeting CD30 have incited a great deal of enthusiasm and are studied in clinical trials.

Is immunohistochemical expression of GATA3 helpful in the differential diagnosis of transformed mycosis fungoides and primary cutaneous CD30-positive T cell lymphoproliferative disorders?

Mycosis fungoides with large cell transformation (MFLCT) can be difficult to distinguish from primary cutaneous CD30+ T cell lymphoproliferative disorders (PC CD30+ LPD), especially primary cutaneous anaplastic large cell lymphoma (PC-ALCL). This diagnostic distinction is critical for appropriate patient management. GATA3 has been proposed to be useful in the discrimination between these two entities. We identified 25 cases of MFLCT and 24 cases of PC CD30+ LPDs (including lymphomatoid papulosis (n=14), PC-ALCL (n=6), and CD30+ LPD, not otherwise specified (n=4)) diagnosed at our institution from 2002 to 2019. Sections from archived specimens were stained to evaluate for GATA3 expression by immunohistochemistry and compared among cutaneous CD30+ T cell LPDs. The majority of the MFLCT cohort had strong, diffuse expression of GATA3 ranging from 0 to 100% of dermal T cells (mean 53.20%) with 15/25 cases (60%) showing GATA3 expression greater than 50%, while the PC CD30+ LPD group showed variable, moderate GATA3 labeling ranging from 0 to 60% of dermal T cells (mean 23.26%), with 5/6 cases (83%) showing GATA3 expression less than 40% (p =0.003). The calculated sensitivity and specificity were 56% and 74%, while positive and negative predictive values were 70% and 61%, respectively. Based on the percent staining of positive cells, using 50% as a cutoff value for expression, GATA3 might be a useful immunohistochemical marker to discriminate MFLCT from PC CD30+ LPDs, including PC-ALCL.

Loss of 5-Hydroxymethylcytosine Is an Epigenetic Biomarker in Cutaneous T-Cell Lymphoma

DNA hydroxymethylation at the 5 position of cytosine (5-hmC) is a product of the TET family of DNA hydroxylases. Accumulating evidence shows that loss of 5-hmC is critical for various biological and pathological processes. However, its level in cutaneous T-cell lymphoma (CTCL) remains largely unknown. Here, we report that the loss of 5-hmC is an epigenetic hallmark of CTCL, with diagnostic and prognostic implications. Immunohistochemistry staining on 90 mycosis fungoides (MF) samples showed a significant decrease of 5-hmC staining in CD4⁺ T cells in patch and tumor stages, especially in MF with large cell transformation, compared with benign inflammatory dermatoses. The 5-hmC staining level decreased with disease progression and showed remarkable loss in the large cells of large cell transformed MF samples, regardless of the CD30 positivity. Furthermore, 5-hmC decrease was correlated to poor overall survival in our patient cohort. Pharmacological augments of global 5-hmC with l-ascorbic acid in CTCL cell lines led to remarkable 5-hmC accumulation and promoted apoptosis in CTCL cell lines, as well as in patient-derived CTCL cells. In conclusion, 5-hmC is an epigenetic mark of predictive value in MF prognosis. Restoration of 5-hmC levels in MF may serve as a therapeutic regimen in CTCL.

Clinically defined subgroups of mycosis fungoides display differing histopathological features at initial biopsy

Most patients with mycosis fungoides (MF) remain in early disease stages but some progress to tumor stage. The individual course of the disease cannot be predicted. We wanted to assess the clinical and histological characteristics of the first available biopsy. An end-of-spectrum approach with two groups was used, comparing MF remaining long-term stable in T1a ('MF stable') and MF with later tumor development or present T3 stage ('MF tumor'). The clinical and histomorphological features of the initial skin biopsy were compared. Patients in the 'MF tumor' group presented initially with higher disease stages. The first biopsies of 'MF tumor' patients showed significantly higher infiltrate density and depth, more large cells and a higher proliferative index. In summary, long-term stable MF seems to differ in clinical and histopathological parameters from MF with T3 evolution/presence already at the time point of the initial biopsy. Our findings might indicate a predetermined biologic behavior.

Large-Cell Transformed Mycosis Fungoides Coexisting with Mycosis Fungoides Bullosa: A Case Report and Review of the Literature

Mycosis fungoides is the most common form of cutaneous T-cell lymphoma. Both large-cell transformed mycosis fungoides and mycosis fungoides bullosa are rare presentations and predict unfavorable prognosis. We report the case of a 61-year-old woman who presented with generalized erythematous scaly annular plaques, and histopathology confirmed the diagnosis of mycosis fungoides. She was treated with various conventional therapies but only achieved partial response and always relapsed after discontinuation of treatment. Her last treatment was combined chemotherapy (CHOP regimen) followed by romidepsin. However, 1 month after the last cycle of romidepsin, she developed multiple ulcerative masses and nodules. Skin biopsy was compatible with CD30+ large cell transformation, and she was treated with a new combination of chemotherapy (ifosfamide, carboplatin, etoposide). One day after receiving chemotherapy, multiple tense bullae on normal-appearing skin and mycosis fungoid plaques erupted. A histological study demonstrated subepidermal blistering with epidermotropism of atypical lymphocytes. Direct immunofluorescence study was negative. The results confirmed the diagnosis of mycosis fungoides bullosa. We present the first reported case of large-cell transformed mycosis fungoides coexisting with mycosis fungoides bullosa.

A new era for cutaneous CD30-positive T-cell lymphoproliferative disorders

Cutaneous CD30+ T-cell lymphoproliferative disorders (CD30+ T-LPD) represent a spectrum encompassing lymphomatoid papulosis (LyP), primary cutaneous anaplastic large-cell lymphoma (pcALCL) and borderline lesions. They share the expression of CD30 as a common phenotypic marker. They differ however in their clinical presentation, the histological features and clinical course. Moreover, LyP and PcALCL show numerous clinical, histological and phenotypic variants. Overlapping features of LyP and pcALCL with themselves and with other cutaneous and systemic lymphomas emphasize the importance of careful clinicopathologic correlation and staging in the diagnosis of CD30+ T-LPD. Furthermore, an increasing number of inflammatory and infectious skin disorders harboring medium-sized to large CD30+ cells have to be considered in the differential diagnosis. Whereas the expression of CD30 in cutaneous CD30+ T-LPD stands for a favourable prognosis, its expression in other cutaneous and systemic lymphomas has a divergent impact. The assessment of CD30 expression does not only provide prognostic information, but is of potential therapeutic relevance as CD30 can serve as a therapeutic target. This review focuses on the clinicopathological and phenotypic spectrum of CD30+ T-LPD, its differential diagnoses and the role of CD30 as a diagnostic, prognostic and therapeutic marker.