CD8+ mycosis fungoides: A wolf in sheep’s clothing?

Sir, CD8+ mycosis fungoides (MF) is a rare form of MF with an indolent course. Herein, we report a rare case of CD8+ fungoid mycosis preceded by lymphomatoid papulosis type D with an aggressive course. A 36-year-old female presented with several papular lesions on the trunk and extremities with a relapsing–remitting course. Histopathology and an immunohistochemical study confirmed CD8-positive lymphomatoid papulosis type D and methotrexate at 25 mg/week was initiated. After a temporary clinical improvement, the lesions worsened, became infiltrated, and grouped as vaguely annular and angular patches with serpiginous borders (Fig. 1). A second scalp biopsy was performed and a diagnosis of CD8+ MF was established. An extension workup was normal, and MF was classified as stage IB. PUVA therapy was started with acitretin at 25 mg/day. After four weeks from the beginning of treatment, the patches completely disappeared but with the concomitant appearance of four subcutaneous tumors. The evolution was spectacular in fifteen days, with the tumors rapidly increasing in size, becoming ulcerative and necrotic, and one being localized in the left cervical area compressing the upper respiratory tract (Fig. 2). A subsequent biopsy revealed massive epidermal and dermal large cell infiltration (Fig. 3a); the tumor cells were positive for CD3, CD8, and CD7 (Fig. 3b) and negative for CD4, CD5, CD3, CD2, and CD30. Antigen Ki-67 was expressed by more than 80% of T-cells (Fig. 3c). A cerebral and thoraco-abdominal CT scan revealed multiple axillary lymph nodes with hypermetabolism on a PET scan. An osteomedullar biopsy was normal, and lactate dehydrogenase (LDH) was increased to 358 U/L. Chemotherapy was performed, but the patient died after two cycles of CHOEP. In contrast to classical CD4+ mycosis fungoides, CD8+ MF is a rare cytotoxic phenotype constituting about 5% of all cases of MF [1]. It belongs to the first group of primary cytotoxic cutaneous lymphomas (PCCL) with a good prognosis, an indolent course, and a slow progression of the lesions over several years [2]. However, rare cases with a more aggressive course have been reported in the literature [3]. The main differential diagnosis of aggressive CD8+ MF is an aggressive epidermotropic cutaneous CD8+ lymphoma that is a rare cutaneous lymphoma with a poor prognosis due to rapid extracutaneous dissemination [4]. The prognosis of the CD8+ subtype of mycosis fungoides (MF) is controversial. More studies are necessary to clarify this subject.

Safety and Danger Considerations of Novel Treatments for Atopic Dermatitis in Context of Primary Cutaneous Lymphomas

The impact of new and emerging therapies on the microenvironment of primary cutaneous lymphomas (PCLs) has been recently raised in the literature. Concomitantly, novel treatments are already used or registered (dupilumab, upadacitinib) and others seem to be added to the armamentarium against atopic dermatitis. Our aim was to review the literature on interleukins 4, 13, 22, and 31, and JAK/STAT pathways in PCLs to elucidate the safety of using biologics (dupilumab, tralokinumab, fezakinumab, nemolizumab) and small molecule inhibitors (upadacitinib, baricitinib, abrocitinib, ruxolitinib, tofacitinib) in the treatment of atopic dermatitis. We summarized the current state of knowledge on this topic based on the search of the PubMed database and related references published before 21 October 2021. Our analysis suggests that some of the mentioned agents (dupilumab, ruxolitinib) and others may have a direct impact on the progression of cutaneous lymphomas. This issue requires further study and meticulous monitoring of patients receiving these drugs to ensure their safety, especially in light of the FDA warning on tofacitinib. In conclusion, in the case of the rapid progression of atopic dermatitis/eczema, especially in patients older than 40 years old, there is a necessity to perform a biopsy followed by a very careful pathological examination.

Primary Cutaneous Lymphoma: Recommendations for Clinical Trial Design and Staging Update from the ISCL, USCLC, and EORTC

The number of patients with primary cutaneous lymphoma (PCL) relative to other non-Hodgkin lymphomas (NHLs) is small and the number of subtypes large. Although clinical trial guidelines have been published for mycosis fungoides/Sézary syndrome (MF/SS), the most common type of PCL, none exist for the other PCLs. In addition, staging in the PCLs has been evolving based on new data on potential prognostic factors, diagnosis, and assessment methods of both skin and extracutaneous disease and a desire to align the latter with the Lugano guidelines for all NHLs. The International Society for Cutaneous Lymphomas (ISCL), the United States Cutaneous Lymphoma Consortium (USCLC), and the Cutaneous Lymphoma Task Force of the European Organization for the Research and Treatment of Cancer (EORTC) now propose updated staging and guidelines for the study design, assessment, endpoints and response criteria in clinical trials for all the PCLs in alignment with that of the Lugano guidelines. These recommendations provide standardized methodology that should facilitate planning and regulatory approval of new treatments for these lymphomas worldwide, encourage cooperative investigator-initiated trials, and help to assess the comparative efficacy of therapeutic agents tested across sites and studies.

Genomic Analysis of Cutaneous CD30-Positive Lymphoproliferative Disorders

Primary cutaneous CD30+ T-cell lymphoproliferative disorders (CD30+ LPD) are the second most common cutaneous lymphomas. According to the World Health Organization (WHO), CD30+ LPD include primary cutaneous anaplastic large cell lymphoma (pcALCL) and lymphomatoid papulosis (LyP) as well as borderline lesions. pcALCL and LyP is thought to represent two ends of a spectrum of diseases that have different clinical presentations, clinical courses, and prognoses in their classic forms, but share the same histology of medium to large CD30+ atypical lymphoid cell infiltrates. Because the behavior of these entities is different clinically and prognostically, we aim to search for oncogenic genomic variants using whole exome sequencing (WES) that drive the development of LyP and pcALCL. Clinical information, pathology, immunohistochemistry, and T-cell rearrangements on six cases of LyP and five cases of pcALCL were reviewed to confirm the rendered diagnosis prior to WES of all specimens. All cases of CD30 LPD had recurrent mutations in at least one of the epigenetic modifying genes, with the most frequent mutations found in the mixed lineage methyltransferase family involved in the methylation of H3K4: CREBBP (27%), KMT2A (36%), KMT2D (36%), SETD2 (27%), and SMARCA4 (27%) (Figure). Within the JAK/STAT pathway, mutations of STAT3 were observed in 2 cases of pcALCL (n=2, 18%), STAT5B in one case of LyP (n=1, 9%) and JAK1 mutation in one case of LyP(n=1, 9%). Lastly, mutations were also identified in the T-cell signaling pathway. 3/5 cases of pcALCL demonstrated loss of function mutations in EOMES, a T-box transcription factor important in lymphocyte development. We had two cases of C-ALCL and one case of LyP with NOTCH1 mutations supporting the importance of this gene in T-cell lymphomas. TP53 mutations and copy number loss is more characteristic of aggressive lymphomas and these abnormalities were absent in pcALCL and LyP and may explain the indolent nature of CD30+ LPD. While the JAK/STAT pathway, T-signaling, and epigenetic alterations possibly play a role in the pathogenesis of these diseases, genes involved in cell-cycle control and apoptosis (ie. TP53) that are characteristic of more aggressive diseases were not identified. Extending this investigation to a larger number of samples will allow us to detect additional mutations that may help distinguish between CD30+ LPDs of LyP and pcALCL as well as other histologic mimics such as systemic ALCL and large cell transformation of MF. Figure 1 Figure 1. Disclosures Abdulla: Caris Life Licenses: Current Employment. Zain: Kiyoaw Kirin, Secura Bio, Seattle Genetics: Honoraria; Secura Bio, DaichiSankyo, Abbvie: Research Funding; Secura Bio, Ono , Legend, Kiyowa Kirin, Myeloid Therapeutics Verastem Daichi Sankyo: Consultancy.

Clinical Guidelines and New Molecular Targets for Cutaneous Lymphomas

Primary cutaneous lymphomas are heterogenous lymphoproliferative disorders. Some patients show rapid progression and the need for treatment of advanced disease is still unmet. The frequency of each subtype of cutaneous lymphoma varies among different ethnic groups, as do the medical systems found in different countries. It is important to know the differences in clinical guidelines in different areas of the world. Although current monochemotherapy with gemcitabine or pegylated liposomal doxorubicin is temporarily effective for mycosis funogides (MF) and Sézary syndrome (SS)—representative types of cutaneous lymphomas—the duration of response is usually limited. Therefore, treatment strategies targeting tumor-specific molecules have been developed. Molecular targets for MS/SS are currently CD30, CCR4, CD25, CD52, and histone deacetylases, most of which are surface molecules specifically expressed on tumor cells. As a result of advances in research techniques, different kinds of genomic alterations in MF/SS have been revealed. Molecular targets for MS/SS in the near future would be CD158k, JAK, PIK3, the mammalian target of rapamycin, and microRNAs, most of which mediate intracellular signaling pathways. Personalized therapy based on the detection of the genetic signatures of tumors and inhibition of the most suitable target molecules constitutes a future treatment strategy for MF/SS.