Hypopigmented Mycosis Fungoides Research Articles

P16 Hypopigmented Mycosis Fungoides in a Caucasian child

Abstract We report a case of hypopigmented MF in an 8-year-old Caucasian boy whose skin had been managed as pityriasis alba for a number of years. On initial presentation to the emergency department, multiple non-itchy scattered hypopigmented macules were incidentally noted on the lower abdomen, groin, lateral flanks and axillae. Physical examination revealed widespread hypopigmented patches. Differential diagnoses included pityriasis alba or post inflammatory hypopigmentation secondary to atopic dermatitis. He was initially managed with mild to moderate corticosteroids and emollients, but continued to develop multiple atypical asymmetrical macules, particularly on the lower abdomen and groin. Although the skin was responsive to anti-inflammatory treatment, given the progression, a skin biopsy was requested. A lesional punch biopsy from the abdomen revealed focal lymphocyte exocytosis and interface change at the epidermis. Given the subtle findings the case was discussed at our histopathology MDT meeting. Further specialist review of the histopathology showed clinicopathological correlation in keeping with CD8+ mycosis fungoides (hypopigmented variant). He is currently managed with regular potent topical steroids, 0.1% topical tacrolimus. TL01 phototherapy has been suggested. Juvenile onset MF constitutes hypopigmented, poikilodermatosis, pityriasis lichenoides-like, folliculotropic, and pigmented purpura- like presentations1. Generally there is no disease progression beyond stage 1A or 1B disease2. Hypopigmented MF is well described in black and Asian skin types but it is also important to appreciate that multiple reoccurring atypical hypopigmented patches in Caucasian skin may also be a variant of hypopigmented MF.

Real-World Clinical Characteristics, Management, and Outcomes of 44 Paediatric Patients with Hypopigmented Mycosis Fungoides.

Hypopigmented mycosis fungoides is a rare form of mycosis fungoides that is characterized by achromic lesions, early onset of disease, a predilection for darker skinned populations, and a predominance of CD8+ T cells. Due to the rarity and heterogeneous presentation of hypopigmented mycosis fungoides, there are no criteria that clearly define the clinical characteristics and treatment regimens for this condition. This retrospective study of 44 paediatric patients with hypopigmented mycosis fungoides aimed to summarize their epidemiological and clinical characteristics and assess the effectiveness and safety of different treatment regimens. Clinical manifestations were further classified into 3 morphological groups: hypopigmented lesions, papules overlying hypopigmented lesions, and erythematous plaques overlying hypopigmented lesions. In addition, the results of this study suggest that interferon alpha might be an effective and well-tolerated therapy that could shorten the treatment time to complete response compared with other treatments. Maintenance therapy and long-term follow-up reduced the recurrence rate.

Basement membrane thickness helps to differentiate hypopigmented mycosis fungoides from clinical and pathological mimickers.

Hypopigmented mycosis fungoides (HMF) is a relatively rare subtype of mycosis fungoides (MF). The diagnosis of HMF can be quite challenging in case of insufficient diagnostic criteria due to the diverse conditions that present with hypopigmented lesions. This study aimed to evaluate the usefulness of the assessment of the basement membrane thickness (BMT) in the diagnosis of HMF. A retrospective study was conducted on biopsy specimens of 21 HMF and 25 non-HMF cases who presented with hypopigmented lesions. The thickness of the basement membrane was evaluated in periodic acid-Schiff (PAS)-stained sections. The mean BMT was significantly higher in the HMF group than in the non-HMF group (P < 0.001). The best cut-off value of mean BMT for the detection of HMF verified in ROC analysis was 32.7 μm (P < 0.001) with a sensitivity of 85.7% and a specificity of 96%. Evaluation of BMT can be a useful tool to distinguish HMF from other causes of hypopigmented lesions in doubtful cases. We suggest the use of " BMT more than 33 μm" as a histopathologic criterion of HMF.

Pediatric Primary Cutaneous Lymphoma in China: A Retrospective Study

Background: The incidence and clinical features of primary cutaneous lymphoma (PCL) tend to differ by age, gender, geographical, and racial variation. All-aged and adult groups of PCL in various regions have been well demonstrated and compared, while the research concentrating on pediatric PCL is rare, especially in Asian countries. Objective: The aim of this study was to investigate the clinical characteristics of PCL in pediatric population at a single center in China. Methods: We conducted a retrospective study of 101 pediatric cases with PCL, diagnosed at the Institute of Dermatology, Chinese Academy of Medical Sciences, from January 2010 to December 2021. Results: Mycosis fungoides (MF), accounting for 41.6% of the total cases, was the most common subtype in pediatric PCL, and the hypopigmented MF accounted for 47.6% of all the MF cases. Lymphomatoid papulosis and chronic active Epstein-Barr virus infection tied for second place with a proportion of 22.8%. Primary cutaneous anaplastic large cell lymphoma, subcutaneous panniculitis-like T-cell lymphoma, primary cutaneous peripheral T-cell lymphoma, rare subtypes and primary cutaneous B-cell lymphoma, respectively, accounted for 2.0%, 4.0%, 4.0%, and 3.0%. Most patients had favorable prognosis during the follow-up. Conclusion: The study suggested that MF was the most common subtype in pediatric PCL in China, and most types of pediatric PCL had favorable prognosis.

Suggested Guidelines for the Treatment of Mycosis Fungoides in Countries with Limited Resources.

The treatment options for mycosis fungoides (MF) have been expanding but unfortunately many of the currently used treatment modalities are unavailable in Egypt and other African/Arab countries. In addition, there is a lack of consensus on the treatment of hypopigmented MF (HMF), which is a frequently encountered variant in our population. We aimed to develop regional treatment guidelines based on the international guidelines but modified to encompass the restricted treatment availability and our institutional experience. Special attention was also given to studies conducted on patients with skin phototype (III-IV). Treatment algorithm was formulated at Ain-Shams cutaneous lymphoma clinic through the collaboration of dermatologists, haematologists, and oncologists. Level of evidence is specified for each treatment option. For HMF, phototherapy is recommended as a first line treatment, while low-dose methotrexate is considered a second line. For early classical MF, we recommend Psoralen-ultraviolet A (PUVA), which is a well-tolerated treatment option in dark phenotype. Addition of either retinoic acid receptor (RAR) agonist and/or methotrexate is recommended as a second line. Total skin electron beam (TSEB) is considered a third-line option. For advanced stage, PUVA plus RAR agonist and/or methotrexate is recommended as first line, TSEB or monochemotherapy is considered a second line option. Polychemotherapy is regarded as a final option. All patients with complete response (CR) enter a maintenance and follow-up schedule. We suggest a practical algorithm for the treatment of MF for patients with dark phenotype living in countries with limited resources.

CD8+ T Lymphocytes in Hypopigmented Mycosis Fungoides: Malignant Cells or Reactive Clone?

Hypopigmented mycosis fungoides (HMF) is the most common type of cutaneous T-cell lymphoma in children (Amorim et al., 2018). HMF has a benign course and rarely progresses past localized disease, a striking difference from classic MF, which sometimes progresses from patches to tumors in an average of 12.4 years. On the basis of the identification of dominant clonal T-cell populations, classic MF is seen as a malignancy of CD4+ skin-resident memory cells, whereas HMF is considered to be a malignancy of CD8+ T cells (El-Shabrawi-Caelen et al., 2002).

LateBr-O-01 - CD8+ T lymphocytes in hypopigmented mycosis fungoides: malignant cells or reactive clone?

LateBr-O-01 - CD8+ T lymphocytes in hypopigmented mycosis fungoides: malignant cells or reactive clone?

Clin-O-01 - Investigating clinical characteristics and outcomes of hypopigmented mycosis fungoides: retrospective review at a single tertiary referral center

Clin-O-01 - Investigating clinical characteristics and outcomes of hypopigmented mycosis fungoides: retrospective review at a single tertiary referral center

34316 Successful treatment of hypopigmented mycosis fungoides in a pediatric patient with excimer laser

A 10-year-old girl with a history of facial pityriasis alba presented with an asymptomatic hypopigmented patch on the right leg. Treatment with triamcinolone cream did not alter the appearance and hair loss was noted within the lesion. After cessation of topical steroids, a biopsy revealed a spongiotic and psoriasiform dermatitis with lymphocyte exocytosis and perifollicular and perieccrine lymphocytic inflammation with a CD8 shift. T-cell gene rearrangement was positive. A diagnosis of hypopigmented mycosis fungoides (MF) was made.

Hypopigmented Mycosis Fungoides: A Clinicopathological Review of 32 Patients.

BackgroundHypopigmented mycosis fungoides (hMF) is gradually acknowledged by more dermatologists, yet a consensus regarding its characteristics is not reached. The profile of Chinese hMF patients has not been deeply reviewed previously. Our research may contribute to the understanding of hMF, especially the Chinese patients with Fitzpatrick phototypes of III and IV.AimTo have a better understanding of hMF in terms of clinical, histopathological and immunohistochemical features in the Chinese population and to determine if there are differences between the Chinese population and other ethnic groups.MethodsWe made a retrospective analysis of clinical, histopathological and immunohistochemical features of 32 hMF patients in our hospital from 2010 to 2020. These features were then summarized and compared with previous reports.ResultsAll patients belonged to Fitzpatrick phototypes of III or IV. Twenty-one male (65.63%) patients and 11 female (34.37%) patients were analyzed, and the male to female ratio was 1.9:1. The age at diagnosis of patients ranged from 4 to 39 years, and the average age at diagnosis of these patients was 18 years, the median age was 16.5. Back was the most frequent site (34.37%). The clinical and histological results of lesions had no distinctive points. Immunohistochemically, among these 32 patients, there were 30 patients whose information was complete, there was 19 patients (63.33%) who were CD8 positive lymphocytes predominance, 9 patients (30%) had CD8 and CD4 positive lymphocyte mixed infiltration, and other 2 patients (6.67%) had CD4 positive lymphocytes predominance. Partial loss of CD7 was only observed in 1 patient (3.33%). Nearly all patients adopted topical nitrogen mustard and topical steroid and most of them had an excellent prognosis.ConclusionThe clinical profiles of hMF in Chinese population shared differences with other ethnic groups, but its histopathological, immunohistochemical results and prognosis condition were resembled with other previous reports. Hence, more patients were needed to find the characteristics of hMF.

PA30: Localized facial hypopigmented mycosis fungoides in younger children of skin type VI presenting as multiple coalescing macules

PA30: Localized facial hypopigmented mycosis fungoides in younger children of skin type <scp>VI</scp> presenting as multiple coalescing macules

Paediatric mycosis fungoides - characteristics, management and outcomes with particular focus on the folliculotropic variant.

The literature on paediatric mycosis fungoides (MF) and especially its folliculotropic variant (FMF) is sparse. To describe the clinical manifestations, treatments, outcomes and long-term course of paediatric MF, including FMF. A retrospective analysis was conducted of all consecutive MF patients diagnosed at ≤18 years attending two medical centres in 1995-2015. The cohort included 71 patients, all but two of whom had early-stage disease: hypopigmented (55%), folliculotropic (42%) and classical MF (39%), alone or in combination. The head and neck area were involved in 43% of patients with early-stage FMF compared to 12% of the non-FMF group (P = 0.004). There was no difference in the involvement of other body areas between the groups. Pruritus, although mild, was more often recorded among patients with early-stage FMF compared to non-FMF (58% vs. 29%, respectively, P = 0.02). Complete response (CR) was achieved in 60 of the 69 patients with early-stage MF (87%) after an average of 1.8 treatment modalities. NBUVB was the most administered treatment to non-FMF patients with CR rates of 63% vs. 29% of FMF patients (P = 0.04). Systemic/bath PUVA and UVA+NBUVB were the most administered treatments to FMF patients with CR rates of 60% vs. 81% for non-FMF patients (P = 0.17). During a mean follow-up of 9.2 years (range 1-24), stage progression was observed in four (6%) of the patients with early-stage disease, two of whom (all FMF) to advanced stage. Paediatric MF presents as an early-stage disease with over-representation of hypopigmented and FMF variants. NBUVB and UVA-based therapies yield good response rates in non-FMF and FMF patients, respectively. Disease course is indolent, and even on relatively long follow-up, it has a very low progression rate from early to advanced-stage disease, occurring in patients with FMF. We propose a treatment algorithm for paediatric MF.

Clinical Patterns and Treatment Response of Patients With Mycosis Fungoides a Retrospective Study

BackgroundMycosis fungoides (MF) is one of the primary cutaneous T-cell lymphomas and is considered to be the most common extranodal non-Hodgkin lymphomas. MF is characterized by different subtypes based on clinical presentation and immunophenotyping studies. We aimed to study the clinical patterns and treatment response in cases of MF among the patients attending a tertiary referral hospital in Saudi Arabia.MethodologyA retrospective study, case record-based study was done to review all the patients diagnosed with MF from January 2011 to May 2016. All cases with histopathological confirmation and immunophenotyping were included in the study. Treatment follow-up was reviewed for 9 months in all cases. Treatment response was graded based on a global physician assessment-complete response, good response, moderate response, and minimal or no response.ResultsOut of 34 cases of MF included in the study, 11 were hyperpigmented MF, 21 were hypopigmented MF, and there was one case each of poikilodermatous MF and pagetoid reticulosis. Of the total, fourteen (66.7%) of hypopigmented MF patients showed a complete response to phototherapy Narrowband UVB (NB-UVB) in combination with topical corticosteroids. Nine (81.8%) of hyperpigmented MF patients showed partial to the phototherapy NB-UVB in combination with the topical corticosteroid. Among the other types; one case of poikilodermatous MF (2.9%) showed a moderate response to phototherapy NB-UVB with topical corticosteroid and systemic acitretin.ConclusionsThe most common type of MF seen in our study was the hypopigmented type, affecting a younger age group, and the same showed a good response to phototherapy NB-UVB combined with topical corticosteroids.

Mycosis fungoides in children and adolescents: A clinicopathological study in Jordan, Middle East

Background: Mycosis fungoides usually affects adults but rarely occurs in children and adolescents with a deceptive clinical picture that simulates more common skin diseases at this age; therefore, the diagnosis can be delayed. Objective: To determine the clinical and histopathological features in a group of patients who developed mycosis fungoides during childhood and adolescence to share experience and to highlight the early diagnosis of mycosis fungoides in this age group. Materials and Methods: A retrospective study was performed, and the clinical and histopathological data for all children and adolescent patients with confirmed mycosis fungoides diagnosis for the last five years were retrieved, reviewed, and analyzed. Results: Seven patients were diagnosed with mycosis fungoides with an age ranging from 5 to 17 (mean age, 10) years, comprising five males and two females patients, with a male-to-female ratio of 2.5:1. Three clinical variants of mycosis fungoides were present in our cases: hypopigmented mycosis fungoides in four patients (57%), poikilodermatous mycosis fungoides in two (29%), and classical mycosis fungoides in one (14%). No more than one variant of mycosis fungoides was observed in any patient. Conclusion: Although mycosis fungoides rarely occurs in children and adolescents, sufficient clinical and histopathological features are required to make the diagnosis. Therefore, it should always be considered in our clinical differential diagnosis in any appropriate clinical setting. A skin biopsy should not be delayed. Study Design: Retrospective study.

Risk Factors for Progression from Early to Advanced Stage Mycosis Fungoides: A Single Center Retrospective Analysis at the Winship Cancer Institute of Emory University

Introduction:Advanced stage mycosis fungoides (MF) has a median survival of 3-5 years, while early stage MF is a chronic disease typically associated with an excellent prognosis and a median survival of 20 years or more. Prior studies suggest approximately 20% of early stage MF may progress to advanced stage, but risk factors for progression remain poorly studied, particularly among African American (AA) patients. We aimed to identify clinic features associated with progression to advanced stage MF in a large urban medical center.MethodsWe performed a retrospective review of 388 patients with early stage (1A-2A) MF at the Winship Cancer Institute of Emory University diagnosed between 1970 and 2021. Clinical data collected from the electronic medical record included demographics, laboratory values, disease characteristics, and therapy. Our primary endpoint was to identify variables associated with progression to advanced stage MF. Progression to advanced stage was defined as a highest overall TNMB stage of 2B-4B. Overall survival (OS) was measured from time of diagnosis to date of death or last follow-up. Kaplan-Meier curves for OS were generated for the whole cohort and by progression group. Descriptive analysis was performed for each variable, and a comparison between patients who did or did not progress to advanced stage was performed using ANOVA for numerical covariates and chi-square test for categorical covariates. The association of baseline variables with OS was modeled by Cox proportional hazards model and multivariable analyses were performed on significant variables.ResultsAmong 388 patients, the median follow up was 5 years (range 0-51). There was even distribution among male (49.0%) and female (51.0%) patients. The median age at diagnosis was 53 years (range 8-95). This population included 41.4% AA, 55.0% White, 2.3% Asian, and 1.3% other races. Stage distribution was as follows: 34.2% (n=133) stage 1A, 51.5% stage 1B (n=200), and 14.2% stage 2A (n=55). Forty-nine patients had hypopigmented MF (45 AA), and 9.4% (n=34) patients developing large cell transformation (LCT) during their disease course. Treatment at diagnosis was topical in 52.3% (n=203), systemic in 1.8% (n=7), radiation in 3.4% (n=13), and multimodality in 29.4% (n=114).Overall, 93 patients (24.1%) progressed to advanced stage. Progression to a higher stage was statistically associated with higher overall TNMB stage at diagnosis (p<0.001), T2 tumor stage (p<0.001), nodal involvement (p=0.031), positive blood flow cytometry (<0.001), T-cell receptor (TCR) clonality in the blood (p=0.014), LCT (p<0.001), and elevated lactate dehydrogenase (LDH) (p<0.001). Patients with hypopigmented MF were less likely to progress (hazard ratio 0.32 (95% CI 0.12-0.84) p=0.020), Sex, race, age, blood stage, and white blood cell count were not associated with risk for progression. Univariate logistic regression is summarized in figure 1.Progression to advanced stage was associated with an increased risk of death (4.75 (0.05-7.38), p < 0.001, figure 2). The median survival for patients who did and did not progress were 11 years (95% CI 7, 15) and 31 years (95% CI 25, not reached), p<0.001 respectively. Other factors associated with an increased risk of death included age > 60 (p <0.001), higher TNMB stage at diagnosis (log rank p<0.001), advanced nodal stage, (p=0.005), positive peripheral blood flow (p=0.010), TCR clonality in the blood (p=0.039), LCT (p< 0.001), elevated LDH (p<0.001), and elevated WBC (p<0.001), while hypopigmented MF was associated with a decreased risk of death (0.28 (0.09-0.90), p=0.021). On multivariable survival analysis controlling for hypopigmented MF, LCT, and stage at diagnosis, only age > 60 (3.32 (2.00-5.51), p<.001) and progression to advanced stage (4.02 (2.38-6.79), p<0.001) remained statistically significant.ConclusionsWe demonstrate that progression to advanced stage is associated with several baseline laboratory and disease characteristics, which bear immediate clinical relevance to the work up and staging of early stage MF. These data suggest that consistent staging and laboratory analyses with imaging for lymph node assessment, peripheral blood flow cytometry, and TCR in all newly diagnosed MF patients may aid in identifying patients at risk for progression to advanced stage disease. [Display omitted] DisclosuresNo relevant conflicts of interest to declare.

Hypopigmented Mycosis Fungoides in Younger Patients: A Mimicker of Common Hypopigmented Inflammatory Rashes

Hypopigmented mycosis fungoides (HMF) is a rare type of cutaneous T-cell lymphoma (CTCL), a non-classic variant among up to 50 variants of mycosis fungoides (MF), that typically affects younger individuals in the second to fourth decades of life of darker skin types. The presenting cutaneous findings of HMF can be mistaken for and mimic other commonly seen hypopigmented skin disorders and misdiagnosed by an untrained eye in the dermatologic and general practice settings. MF has many different variants, and affects both children and adults. For the purpose of this article, the discussion will be limited to HMF specifically presenting in younger patients. With limited literature on HMF commonly affecting the younger generations, knowledge of how to diagnose and treat this cutaneous malignancy is lacking among clinicians. The goal of this CME article is to provide more awareness to clinicians on this rare form of CTCL, thus improving patient care through early detection and treatment in this patient population.

Review article: Emerging issues in pediatric skin of color, Part 2.

Dermatology for pediatric skin of color is the application of dermatology to the genetically diverse and distinctive segment of the pediatric population that includes children of non-White racial and ethnic groups with increased pigmentation including individuals of Asian, Hispanic/LatinX, African, Native American, Pacific Island descent, indigenous people among others with overlap in particular individuals, and mixtures thereof. The discipline of pediatric skin of color can be challenging with difficulty in diagnosis of common conditions due to underlying pigmentation, variations in common hair styling practices, and differences in demographics of cutaneous disease. Whereas some conditions are more common in children of color, other conditions have nuances in clinical appearance and therapeutics with regard to skin color. This article, the second of the series, focuses on inflammatory skin disease nuances, melanocytic disorders, and hypopigmented mycosis fungoides.

Pediatric Mycosis Fungoides: Retrospective Analysis of a Series With CD8 + Profile and Female Predominance.

Mycosis fungoides (MF) in children is a rare disease and there are limited data regarding the behavior of the disease in this age group. We aimed to collect additional data to better understand the clinicopathologic features of MF in children. This study was a retrospective analysis of pediatric MF patients (diagnosed at age 0 to 18 y). Thirteen pediatric patients with MF were identified. Female predominance was observed with a ratio of 1.6:1. Median values for age of onset of skin lesions and age at the time of histologic diagnosis were 5 and 12 years, respectively. All patients had early stage (stage IA to IIA) of MF at the time of diagnosis. Hypopigmented MF comprised 77% of all study patients, followed by classic MF (15%) and pagetoid reticulosis (8%). The lower extremity (especially proximal leg) followed by trunk and upper extremity were most commonly affected sites. Seven of 9 patients who had available immunohistochemistry data showed CD8 + predominance. Five of 8 patients whose follow-up data was available, achieved complete response with narrowband ultraviolet B treatment, while 2 and 1 had near complete response and partial response, respectively. Our study demonstrated female sex and CD8 + profile predominance. Hypopigmented MF constituted the majority of cases. We observed good responses with narrowband ultraviolet B treatment.

Characteristics and outcomes of 727 patients with mycosis fungoides and Sézary syndrome from a Brazilian cohort.

Mycosis fungoides (MF) and Sézary syndrome (SS) are the most prevalent cutaneous lymphomas. They were not described in a large Brazilian cohort yet. We aimed, with this single-center, retrospective cohort analysis, to describe the characteristics and outcomes of MF/SS in a tertiary public health service in Brazil. MF/SS patients evaluated at the University of São Paulo Medical School between 1989 and 2018 were included. Data were collected at diagnosis. Demographic, clinical, histopathological, immunopathological, molecular, laboratory, and follow-up data were analyzed. Among 727 patients, 92.6% (673) were diagnosed with MF, 7.4% (54) with SS. There were 51.2% (372) of males, 48.8% (355) of females. The median age was 51.8 years; it was higher in erythrodermic MF (60.2) and SS (60.9). Among MF, 41.8% (281) had classic MF, 4.9% (33) folliculotropic MF, 1.8% (12) granulomatous slack skin, and 0.3% (2) pagetoid reticulosis. Common subtypes included erythrodermic (14.1%, 95), hypopigmented (10.8%, 73), and poikilodermatous MF (10.8%, 73). Extracutaneous involvement was rare. Five, 10, 20, and 30-year overall survival rates were 97.3%, 92.4%, 82.6%, and 82.6% for early-stage, and 58.6%, 42.7%, 20.8%, and 15.4% for advanced-stage disease, respectively. After multivariate analysis, SS diagnosis, folliculotropic MF, erythrodermic MF, clinical stage, age (≥60 years), increased lactate dehydrogenase, and large cell transformation conferred poorer prognosis. We observed a higher percentage of hypopigmented MF compared to the literature, and demographic (older age) and prognostic (poorer prognosis) similarities between erythrodermic MF and SS, suggesting a possible relationship between these erythrodermic lymphomas. Factors associated with a poorer prognosis were compatible with the literature.

Evaluation of Melanocyte Loss in Mycosis Fungoides Using SOX10 Immunohistochemistry.

Mycosis fungoides (MF) is a subtype of primary cutaneous T-cell lymphoma (CTCL) with an indolent course that rarely progresses. Histologically, the lesions display a superficial lymphocytic infiltrate with epidermotropism of neoplastic T-cells. Hypopigmented MF is a rare variant that presents with hypopigmented lesions and is more likely to affect young patients. The etiology of the hypopigmentation is unclear. The aim of this study was to assess melanocyte loss in MF through immunohistochemistry (IHC) with SOX10. Twenty cases were evaluated, including seven of the hypopigmented subtype. The neoplastic epidermotropic infiltrate consisted predominantly of CD4+ T-cells in 65% of cases; CD8+ T-cells were present in moderate to abundant numbers in most cases. SOX10 IHC showed a decrease or focal complete loss of melanocytes in 50% of the cases. The predominant neoplastic cell type (CD4+/CD8+), age, race, gender, histologic features, and reported clinical pigmentation of the lesions were not predictive of melanocyte loss. A significant loss of melanocytes was observed in 43% of hypopigmented cases and 54% of conventional cases. Additional studies will increase our understanding of the relationship between observed pigmentation and the loss of melanocytes in MF.