Assessing T-cell receptor clonality by next-generation sequencing in atypical cutaneous lymphoid infiltrates and cutaneous T-cell lymphoma: A scoping review.

The diagnosis of cutaneous T-cell lymphoma (CTCL) remains challenging. Demonstration of a clonal T-cell population using T-cell receptor (TCR) gene rearrangement studies by next-generation sequencing (NGS) has been explored in several studies. This review summarizes the current literature on NGS-based sequencing methods for the assessment of TCR clonality in the evaluation of atypical cutaneous lymphoid infiltrates and CTCL on behalf of the American Society of Dermatopathology Appropriate Use Criteria Committee (lymphoproliferative subgroup). PubMed was searched for relevant articles, including CTCL and NGS, for clonality from 1967 to 2022. Thirteen studies were included in the analysis. The skin was the most commonly assayed compartment with TCR NGS. Sensitivity for TCR NGS in the skin ranged between 69% and 100%, compared to 44%-72% for polymerase chain reaction (PCR)-capillary electrophoresis. Specificity for TCR NGS in the skin ranged from 86% to 100%, compared to 77%-88% for PCR capillary electrophoresis. TCR NGS was also reported to have potential prognostic value in CTCL and can also be used to detect relapse and/or minimal residual disease after treatment.

Cutavirus Infection in Large-Plaque Parapsoriasis, a Premalignant Condition of Mycosis Fungoides.

BACKGROUND: Cutavirus (CuV) is associated with mycosis fungoides; however, the CuV status in parapsoriasis en plaques (PP), a premalignant inflammatory condition of mycosis fungoides, has not been fully delineated. METHODS: Fifty-five Japanese patients with chronic inflammatory skin diseases, including 13 patients with PP, were studied. RESULTS: CuV DNA was detected significantly more frequently in biopsies of the lesional skin from patients with PP (38%; 4 of 13) than in those from patients with other inflammatory skin diseases (2%; 1 of 42; P = .009). All CuV-positive PP cases were of the large-plaque parapsoriasis (LPP) subtype. The viral loads ranged from 83 450 to 2 164 170 copies/103 cells. We recovered near-full-length CuV sequences from the CuV-positive LPP biopsies, all of which were of the Japanese/Asian genotype. The CuV genome appeared to be present within lymphoid cells infiltrating the epidermis and dermis. CuV NS1 and VP1 gene transcripts were also detected in the affected tissues. CONCLUSIONS: The detection of high levels of CuV DNA with the expression of viral mRNA suggests a potential role for CuV in the pathogenesis of LPP, making it necessary to study further the impact of CuV, especially regarding the viral genotype, on the outcomes of patients with CuV-positive LPP.

A retrospective study of prognostic factors and treatment outcome in advanced-stage Mycosis Fungoides and Sezary Syndrome.

Background: Mycosis fungoides (MF) and Sezary Syndrome (SS) comprise over half of all Cutaneous T-cell lymphoma diagnoses. Current risk stratification is largely based on TNMB staging, few research investigated the prognostic value of clinical exams. Current systemic therapy for advanced disease includes immunomodulatory drugs, chemotherapy, and HADC inhibitors. Few clinical trials or retrospective research compared the efficacy of different drugs.Method: Here, we performed a retrospective analysis of prognostic factors and treatment outcomes of 92 patients diagnosed with MF/SS at the Peking Union Medical College Hospital from 2013-2023.Results: Cox regression analysis identified that age ≥ 50 years, WBC ≥ 8 × 109/L, serum LDH ≥ 250U/L, ß2-MG ≥ 4.50 mg/L, and stage IV were associated with reduced overall survival, age ≥ 50 years, serum LDH ≥ 250U/L and stage IV were associated with reduced progression free survival. Kaplan-Meier analysis established that immunomodulatory therapy was associated with longer progression free survival.Conclusion: These results suggested new factors in predicting prognosis and selecting appropriate treatments in patients with advanced MF/SS.

Coexistence of large cell transformed mycosis fungoides and diffuse large B-cell lymphoma in one patient.

Diffuse large B-cell lymphoma (DLBCL) is the most common and aggressive subtype of non-Hodgkin lymphoma. The overall risk of developing DLBCL is increased in patients with other lymphomas, such as mycosis fungoides (MF). In this report, we present an 81-year-old female with early-stage MF who simultaneously progressed to tumor stage, large-cell transformed (LCT) MF and developed a primary DLBCL in a lymph node (LN). She presented with a tumor on her leg and new lymphadenopathy in her right axilla. Skin biopsy of the tumor revealed infiltration of large atypical CD3+, CD4+, and CD30+ cells, and a smaller portion of CD8+ cells in the dermis, consistent with LCT MF. Biopsy of the axillary LN revealed diffuse sheets of CD20+, BCL-2+, c-MYC+, and CD10- cells, highly suggestive of double expressor DLBCL. High-throughput sequencing revealed monoclonal T cells in the skin tumor and a monoclonal B-cell population in the LN. The above findings led to simultaneous diagnoses of LCT MF and nodal double expressor DLBCL. Our case demonstrates the importance of performing a full pathological workup in cutaneous T-cell lymphoma patients presenting with lymphadenopathy.

Hair Shaft Abnormalities as a Dermoscopic Feature of Mycosis Fungoides: Pilot Results.

INTRODUCTION: Diagnosis of persistent erythematous, scaly patches, or plaques can be complex since psoriasis (Ps), eczematous dermatitis (ED), and mycosis fungoides (MF) can be considered. Dermoscopy, which is a noninvasive diagnostic tool, is commonly used to examine blood vessels, scales, and background color; however, research on hair shaft evaluation in inflammatory dermatoses remains scarce. The aim of the study was dermoscopic evaluation of hair shafts in skin lesions localized on the non-scalp skin areas in patients diagnosed with MF, Ps, and ED. METHODS: This was a retrospective evaluation of 55 patients diagnosed with MF, Ps, and ED. Photographic and dermoscopic documentation of these patients and detailed medical history were evaluated. RESULTS: A total of 21 patients with MF, 21 patients with Ps, and 13 patients with ED were evaluated. The examination revealed the presence of various abnormalities of hair shafts (e.g., numerous pili torti, single pili torti, 8-shaped hairs, pigtail hairs, broken hairs, hair shafts rapidly tapered over long sections, hair shafts irregular in thickness, angulated hairs, branched hairs, the presence of trichorrhexis nodosa, and monilethrix-like hairs), yellow dots, and black dots. The presence of pili torti was found in 80% of patients with MF, compared with 16% of patients with Ps and 8% of patients with ED (p < 0.005), with multiple pili torti found only in MF patients (67%) (p < 0.005). Statistically significant differences also applied to hair shafts rapidly tapering over long sections and 8-shaped hairs, which occurred only in MF patients (p < 0.005 and p = 0.035, respectively). CONCLUSIONS: The presence of hair shaft abnormalities such as numerous pili torti, 8-shaped hairs, and hair shafts rapidly tapering over long sections is an important criterion that should be considered in the dermoscopic differentiation of the patchy/plaque mycosis fungoides and inflammatory dermatoses, such as psoriasis and eczematous dermatitis localized on the non-scalp skin areas.

[Translated article] Survival Analysis and Prognostic Factors in a Case Series of 148 Cutaneous T-Cell Lymphomas.

BACKGROUND AND OBJECTIVE: Cutaneous T-cell lymphomas (CTCL) such as mycosis fungoides (MF) and Sézary syndrome (SS) are rare lymphomas with varying prognoses. The aim of the study was to describe the survival of a cohort of patients with MF/SS and evaluate the prognostic factors impacting disease survival. MATERIALS AND METHODS: All cases of MF/SS diagnosed from 2008 through 2022 were retrospectively analyzed. The demographic variables, histological parameters, and analytical data were analyzed too. Progression-free survival (PFS) and disease-specific survival (DSS) were calculated. RESULTS: A total of 148 cases were included. A total of 121 (82%) and 27 cases were diagnosed with MF, and SS, respectively. A total of 37 patients (25%) experienced progression at some point disease progression. The median PFS and median DSS were 127 and 135 months, respectively. Age >60 years, diagnosis of SS, the presence of large cell transformation (LCT) at diagnosis, folliculotropism in early stages, high Ki-67 expression, the presence of the clonal T-cell receptor (TCR) in blood, elevated LDH and B2M levels, and advanced stages (IIB, IVA, T3, T4, N3/Nx) were associated with worse prognosis across the entire cohort. CONCLUSIONS: Stage IVA and the presence of LCT at diagnosis stood out as independent factors of unfavorable prognosis. LCT was the variable that most significantly impacted the patients' survival and was closely associated with tumor skin involvement and stage IIB.

The efficacy of long-term psoralen plus ultraviolet A and low-dose interferon-a combination therapy in mycosis fungoides: A literature review.

BACKGROUND/PURPOSE: Interferon (IFN)-a is often used in combination with psoralen plus ultraviolet A (PUVA) in patients with mycosis fungoides (MF) refractory to skin-targeted therapies in early or advanced stages. The main objective is to evaluate the effectiveness of combined PUVA and low-dose IFN-α-2a therapy in patients with early- and advanced-stage MF. METHODS: Sixty-eight patients who received a combination of PUVA twice or thrice a week and INF-a 3 MU thrice a week for at least 3 months were reviewed retrospectively. The treatment response was evaluated as complete remission (CR), partial remission, stable disease, or progression. RESULTS: At the initiation, the majority of patients (66.2%) had early-stage disease. In 27.9% of cases, this was the initial treatment administered following the diagnosis of MF. The median duration of combination therapy was 11 months. Complete remission was achieved in 45.6% of the patients with an overall response rate of 60.3%. The mean duration of response was 5 months. Complete remission was statistically significantly higher in early-stage patients (p < .05). No statistically significant correlation was observed between CR and gender, histopathological features, or laboratory parameters. In patients with CR, 80% experienced relapse, significantly higher in early-stage patients (p < .05). However, there was no significant difference in disease-free survival between early and advanced stages (p > .05). CONCLUSIONS: The study results indicated that PUVA + low-dose INF-a combination therapy was more effective in the early stage than in the advanced stage. Additionally, there was a high relapse rate after the cessation of treatment in patients who achieved CR.

Mogamulizumab-associated rash - Case series and review of the literature.

Mogamulizumab, a monoclonal antibody directed against CC chemokine receptor 4, is approved as a second-line treatment of mycosis fungoides and Sézary syndrome. One of the most common side effects is mogamulizumab-associated rash (MAR), which can present in a variety of clinical and histological types. Clinically, it can be difficult to differentiate between MAR and progression of the underlying disease, so histological examination is crucial for clinicopathological correlation. Current data analyses suggest that MAR is more common in patients with Sézary syndrome and is associated with a significantly better response to treatment, making the distinction from disease progression particularly important. The management of MAR depends on its severity, and therapy may need to be paused. This article presents three cases from our clinic and reviews the current literature on MAR. It emphasizes the importance of understanding MAR in the management of patients with cutaneous lymphomas.

The Prognostic Value of Histopathological Features in Early-Stage Mycosis Fungoides: Insights from a Retrospective-Prospective Cohort Study.

Primary cutaneous lymphomas (PCLs), especially mycosis fungoides (MF), pose significant diagnostic and therapeutic challenges. This study aims to correlate initial histological features with the disease course and survival in MF patients. A retrospective-prospective cohort study was conducted on 83 patients diagnosed with early-stage MF at the Departments of Dermatovenerology and Pathology, UHC Zagreb, from January 2003 to December 2012. The analyzed histopathological parameters included lichenoid dermal lymphocyte infiltrate, Pautrier microabscesses, and lymphocyte atypia. Patients with more than 30 guardian lymphocytes per 100 keratinocytes exhibited worse overall and progression-free survival. Furthermore, those with over 50% atypical lymphocytes demonstrated a faster progression rate. A dense lichenoid dermal infiltrate and a high count of lymphocyte "keepers" significantly increased the mortality risk within five years of diagnosis. This study did not fully confirm the hypothesis regarding the prognostic value of large Pautrier microabscesses but highlighted the importance of dense lichenoid infiltrates. The study identified new potential histopathological prognostic factors in early-stage MF, suggesting the need for larger studies to confirm these findings. The identification of such predictors could enhance the prognostic stratification and guide more tailored therapeutic approaches for MF patients.

Mycosis Fungoides Presenting With Multiple Tumors on the Face.

An 84-year-old female experienced progressive erythema on her limbs and chest over the past year. Initially managed with topical steroids, the erythema eventually spread throughout her body, forming erosions. A biopsy confirmed the diagnosis of mycosis fungoides (MF) (Stage IIB, T2bN0M0B0). Treatment with oral bexarotene (300 mg/day) and narrow-band UVB therapy showed limited improvement. Electron beam therapy (30 Gy in 10 fractions) applied to facial and plantar tumors resulted in a reduction of the tumors. This case highlights the treatment of tumors of MF on the face showing the effectiveness of combining electron beam therapy with bexarotene.

Effectiveness of narrowband ultraviolet B monotherapy versus combination therapy with systemic agents in patients with early-stage mycosis fungoides and the association with plaque lesions.

OBJECTIVE: Narrowband ultraviolet B (NB-UVB) has been recommended as first-line therapy for early-stage mycosis fungoides (MF) in international guidelines. NB-UVB can be used as monotherapy or part of a multimodality treatment regimen. There is limited evidence on the effectiveness and optimal patients of NB-UVB in combination with systemic therapies in MF. We aimed to assess the effectiveness of the combination versus NB-UVB monotherapy in early-stage MF and if plaque lesion status was related to these effects. METHODS: This observational cohort study included 247 early-stage MF patients who had received NB-UVB combined with systemic therapies vs. NB-UVB monotherapy from 2009 to 2021. The primary outcome was partial or complete response. Overall response rate and median time to response were calculated. Hazard ratios (HRs) were estimated using the Cox model. RESULTS: In 139 plaque-stage patients, the response rate for combination therapy group was higher than that of monotherapy group (79.0% vs. 54.3%, p = 0.006). The adjusted HR for combination therapy compared with NB-UVB monotherapy was 3.11 (95% CI 1.72-5.63). The combination therapy group also showed shorter time to response (4 vs. 6 months, p = 0.002). In 108 patch-stage patients, the response rate and time to response in two treatment groups showed no significant difference. There was therefore an observed interaction with patients' plaque lesion status for the effect size of NB-UVB combination therapy. No serious adverse events were observed. CONCLUSIONS: Adding systemic treatments to NB-UVB did not improve the treatment outcome of patch-stage patients, but it surpassed NB-UVB monotherapy for early-stage patients with plaques.

Mycosis fungoides refractory to treatment - importance of a multidisciplinary approach.

We report a case of difficult-to-control mycosis fungoides (MF), where the role of the dental surgeon was crucial for the control and prognosis of the disease. A 62-year-old female patient diagnosed with MF had a previous record of red patches and small raised bumps on the face, along with a cancerous growth in the cervical and vulvar region. The patient was initially treated with methotrexate and local radiotherapy without resolution. Chemotherapy with cyclophosphamide, doxorubicin, vincristine, and prednisone was then started (CHOP protocol). The dental team of a reference hospital was consulted to evaluate swelling in the anterior region of the palate, which had been developing for two months, reporting discomfort when eating. The role of the dentistry team was fundamental in the differential diagnosis of oral lesions with dental infections, second neoplasia, or even a new site of disease manifestation, in addition to controlling mucosal changes resulting from chemotherapy. After ruling out dental infection, the dentistry team performed a lesion biopsy to confirm the diagnosis. The histopathological and immunohistochemical analysis showed atypical lymphoid infiltration of T cells (CD3+/CD4+/CD7-/CD8-), coexpression of CD25, and presence of CD30 cells, corresponding to the finding for MF. Identifying CD30 + allowed for a new chemotherapy protocol with brentuximab vedotin (BV) combined with gemcitabine. This protocol effectively controlled MF, which previous protocols had failed to do. The diagnosis by the dental team was essential for therapeutic change and improvement of the patient's clinical condition without the need for invasive medical procedures.

Phase I/II clinical trial of brentuximab vedotin for pretreated Japanese patients with CD30-positive cutaneous T-cell lymphoma.

Brentuximab vedotin (BV), a conjugate of anti-CD30 antibody and monomethyl auristatin E, has emerged as a promising treatment option for refractory CD30+ mycosis fungoides (MF) and primary cutaneous anaplastic large-cell lymphoma (pcALCL). BV has been shown to be safe and effective in treating Hodgkin's lymphoma and peripheral T-cell lymphoma. This multicenter, prospective, single-arm phase I/II study evaluated the efficacy of BV in Japanese patients with CD30+ cutaneous lymphomas, namely CD30+ cutaneous T-cell lymphoma. Participants were divided into two groups: those with CD30+ MF or pcALCL (cohort 1, n = 13) and those with CD30+ lymphoproliferative disorders other than those in cohort 1 (cohort 2, n = 3). The studied population included the full analysis set (FAS), modified FAS (mFAS), and safety analysis set (SAF). These sets were identified in cohorts 1 and 1 + 2 and labeled FAS1 and FAS2, mFAS1 and mFAS2, and SAF1 and SAF2, respectively. Each treatment cycle lasted 3 weeks, and BV was continued for up to 16 cycles after the third cycle based on treatment response. The primary endpoint was the 4-month objective response rate (ORR4) determined by the Independent Review Forum (IRF). ORR4 was 69.2% for FAS1 and 62.5% for FAS2 (P < 0.0001). Secondary endpoints of ORR, assessed using the global response score (53.8% in FAS1) and modified severity-weighted assessment tool (62.5% in FAS1), using the IRF, provided results comparable to the primary findings. The incidence of ≥grade 3 adverse events (≥15%) in SAF1 was peripheral neuropathy in three patients (23%) and fever and eosinophilia in two patients (15%). In conclusion, BV showed favorable efficacy, tolerability, and safety profile in Japanese patients with relapsed or refractory CD30+ primary cutaneous T-cell lymphoma. The trial was registered with University Hospital Medical Information Network Clinical Trials Registry, Japan (protocol ID: UMIN000034205).

Advances in the pharmacological management of cutaneous T-cell lymphoma.

INTRODUCTION: Current treatment guidelines for cutaneous T cell lymphoma (CTCL) advocate a stage-driven approach, considering clinical presentation, symptom burden, and patient comorbidities. Therapy selection hinges on factors like disease subtype, severity, and treatment availability. The primary goal is to enhance the quality of life by mitigating symptoms, as achieving lasting complete remission is infrequent. AREAS COVERED: Over the past decade (2013-2023), the therapeutic landscape of CTCL has experienced substantial transformation with the introduction of innovative therapies. This review explores the main pivotal developments in traditional treatment schedules and recently introduced drugs, aiming to offer clinicians and researchers a thorough perspective on the decade's progress in the field. EXPERT OPINION: Despite the progress made in CTCL therapeutics, ranging from topical chemotherapeutics to immunomodulatory agents, several unmet needs persist. Firstly, there is a pressing need for the incorporation of readily available predictors for treatment response, encompassing clinical, pathological, and molecular features. Secondly, a more profound comprehension of the tumor microenvironment is imperative to optimize the landscape of targetable molecules. Lastly, the undertaking of studies on combination regimens should be encouraged as it enhances therapy efficacies by synergistically combining agents with diverse modes of action.

Morphoea presenting histopathologically as mycosis fungoides: an illustrative series of four cases.

AIMS: There have been exceptional reports of morphoea presenting with epidermal changes overlapping histopathologically with cutaneous T cell lymphoma of the mycosis fungoides type (MF). This phenomenon gives rise to an ambiguous clinicopathological scenario in which distinguishing these conditions may be challenging. The aim of this study is to characterise the clinical, histopathological and molecular findings of this phenomenon through a case series. METHODS AND RESULTS: Four patients with classical clinical presentation of morphoea but unusual histopathology displaying typical findings of morphoea, together with intra-epidermal CD8 positive lymphocytes indistinguishable from MF, were identified. The clinical phenotypes of morphoea were varied, and they all presented early in the active phase of the disease. They all exhibited intra-epidermal lymphocytes with tagging and cytological atypia. Pautrier-like microabscesses were also seen. Using molecular analysis, two cases showed clonal TCR gene rearrangement. Follow-up of all cases has been consistent with classical morphoea. CONCLUSION: Early morphoea can seldom present with atypical clonal intra-epidermal lymphocytes indistinguishable from MF. The fact that these changes can occur in several different clinical subtypes of morphoea raises the possibility that this could be a pattern of inflammation in early disease more common than currently appreciated.

Predictors for the use of systemic therapy in stage IB Mycosis fungoides.

BACKGROUND: The PROspective Cutaneous Lymphoma International Prognostic Index (PROCLIPI) study is aprospective analysis of an international database. Here we examine front-line treatments and quality of life (QoL) inpatients with newly diagnosed mycosis fungoides (MF). OBJECTIVES: To identify (i) differences in first-line approaches according to tumour-nodes-metastasis-blood (TNMB)staging; (ii) parameters related to a first-line systemic approach and (iii) response rates and QoL measures. METHODS: In total, 395 newly diagnosed patients with early-stage MF (stage IA-IIA) were recruited from 41 centresin 17 countries between 1 January 2015 and 31 December 2018 following central clinicopathological review. RESULTS: The most common first-line therapy was skin-directed therapy (SDT) (322 cases, 81·5%), while a smallerpercentage (44 cases, 11·1%) received systemic therapy. Expectant observation was used in 7·3%. In univariateanalysis, the use of systemic therapy was significantly associated with higher clinical stage (IA, 6%; IB, 14%; IIA,20%; IA-IB vs. IIA, P < 0·001), presence of plaques (T1a/T2a, 5%; T1b/T2b, 17%; P < 0·001), higher modified Severity Weighted Assessment Tool (> 10, 15%; ≤ 10, 7%; P = 0·01) and folliculotropic MF (FMF) (24% vs. 12%, P = 0·001). Multivariate analysis demonstrated significant associations with the presence of plaques (T1b/T2b vs.T1a/T2a, odds ratio 3·07) and FMF (odds ratio 2·83). The overall response rate (ORR) to first-line SDT was 73%,while the ORR to first-line systemic treatments was lower (57%) (P = 0·027). Health-related QoL improvedsignificantly both in patients with responsive disease and in those with stable disease. CONCLUSIONS: Disease characteristics such as presence of plaques and FMF influence physician treatment choices,and SDT was superior to systemic therapy even in patients with such disease characteristics. Consequently, futuretreatment guidelines for early-stage MF need to address these issues.

Estimation of the tissue and serum levels of IL-35 in Mycosis fungoides: a case-control study.

Mycosis fungoides (MF) is the most common primary cutaneous T-cell lymphoma (CTCL) with its etiology not yet fully understood. Interleukin (IL)-35 is an inhibitory cytokine that belongs to the IL-12 family. Elevated IL-35 in the plasma and the tumor microenvironment increases tumorigenesis and indicates poor prognosis in different types of malignancies. The objective of this study is to estimate the expression levels of IL-35 in tissue and serum of MF patients versus healthy controls. This case-control study included 35 patients with patch, plaque, and tumor MF as well as 30 healthy controls. Patients were fully assessed, and serum samples and lesional skin biopsies were taken prior to starting treatment. The IL-35 levels were measured in both serum and tissue biopsies by ELISA technique. Both tissue and serum IL-35 levels were significantly higher in MF patients than in controls (P < 0.001) and tissue IL-35 was significantly higher than serum IL-35 in MF patients (P < 0.001). Tissue IL-35 was significantly higher in female patients and patients with recurrent MF compared to male patients and those without recurrent disease (P < 0.001). Since both tissue and serum IL-35 levels are increased in MF, IL-35 is suggested to have a possible role in MF pathogenesis. IL-35 can be a useful diagnostic marker for MF. Tissue IL-35 can also be an indicator of disease recurrence.

Null T-cell phenotype mycosis fungoides with aberrant CD20 and CD56 expression: A diagnostic dilemma.

Mycosis fungoides (MF) represents the most common type of primary cutaneous T-cell lymphoma. Recognition of MF variants with divergent immunophenotypes is important for accurate diagnosis and appropriate management, as they can be confused with other lymphoma subtypes. We present a case of a 49-year-old male previously diagnosed with a cutaneous lymphoproliferative disorder with an unusual NK/T-cell phenotype. He presented with a 10-year history of pelvic girdle rash involving the right hip and upper thigh. The lesions were characterized as atrophic patches concentrated in sun-protected areas and involving 10% of the body surface area. Shave biopsies revealed an atypical epidermotropic infiltrate composed of hyperchromatic small to medium-sized lymphocytes with perinuclear halos and "tagging" along the dermal-epidermal junction. The immunophenotype was unusual in that the neoplastic lymphocytes showed complete loss of pan T-cell antigens along with expression of CD56, cytotoxic markers, and weak CD20. All other B-cell markers were negative. The combination of clinical findings, in addition to the histopathologic and immunophenotypic profile, were diagnostic of null T-cell phenotype MF with aberrant expression of CD56 and CD20. Null T-cell phenotype MF is very uncommon, can be diagnostically challenging, and can mislead the diagnosis of aggressive lymphoma subtypes.