Quantitation of intraepidermal T-cell subsets in formalin-fixed, paraffin-embedded tissue helps in the diagnosis of mycosis fungoides

Clinical, histopathological and immunohistochemical evaluation of ultraviolet A1 treatment in early-stage mycosis fungoides

BACKGROUND/PURPOSE

Mycosis fungoides (MF) is the most common variant of cutaneous T-cell lymphomas primarily involving the skin. Early-stage MF is characterised by non-specific skin lesions and non-diagnostic biopsies. While skin-focused treatments, such as PUVA and narrowband UVB (nbUVB), are the most frequently recommended treatments, the UVA1 efficacy has been researched in recent years. The purpose of this study was to evaluate the clinical, histopathological and immunohistochemical aspects of UVA1 treatment in patients with early-stage MF.

METHODS

The modified severity weighted assessment scale (mSWAT) was used for total skin body scoring before and after treatment. Skin punch biopsies were taken from the patients before and after treatment. UVA1 therapy was performed five times each week.

RESULTS

This study included 26 patients with early-stage MF. The total number of UVA1 sessions varied between 15 and 34. Complete response was observed in 8 (30.8%) of 26 patients (30.8%). The median mSWAT score decreased statistically significantly from 7.1 to 2.0 after treatment (p < .001). Histopathological complete response was observed in 2 (9.5%) of 21 patients. A statistically significant decrease in dermal interstitial infiltrate was observed on histopathological examination after treatment (p = .039). Epidermal CD4/CD8 levels decreased statistically significantly higher from a median of 2.5-1.2 in the complete clinical response group after treatment (p = .043).

CONCLUSION

According to our results, UVA1 treatment has an effect on early-stage MF in terms of clinical, histopathological and immunohistochemistry.

Histology-based classifier to distinguish early mycosis fungoides from atopic dermatitis

BACKGROUND

Histopathological differentiation of early mycosis fungoides (MF) from benign chronic inflammatory dermatoses remains difficult and often impossible, despite the inclusion of all available diagnostic parameters.

OBJECTIVE

To identify the most impactful histological criteria for a predictive diagnostic model to discriminate MF from atopic dermatitis (AD).

METHODS

In this multicentre study, two cohorts of patients with either unequivocal AD or MF were evaluated by two independent dermatopathologists. Based on 32 histological attributes, a hypothesis-free prediction model was developed and validated on an independent patient's cohort.

RESULTS

A reduced set of two histological features (presence of atypical lymphocytes in either epidermis or dermis) was trained. In an independent validation cohort, this model showed high predictive power (95% sensitivity and 100% specificity) to differentiate MF from AD and robustness against inter-individual investigator differences.

LIMITATIONS

The study investigated a limited number of cases and the classifier is based on subjectively evaluated histological criteria.

CONCLUSION

Aiming at distinguishing early MF from AD, the proposed binary classifier performed well in an independent cohort and across observers. Combining this histological classifier with immunohistochemical and/or molecular techniques (such as clonality analysis or molecular classifiers) could further promote differentiation of early MF and AD.

Paediatric Mycosis Fungoides: Clinical Variants, Treatment Modalities and Response to Therapy

Mycosis fungoides is a rare cutaneous lymphoma in the paediatric population. The aim of this study was to examine the epidemiological, clinical, and histological characteristics, as well as the treatment modalities and response to therapy of paediatric patients with mycosis fungoides. This retrospective cohort study reviewed the records of 37 paediatric patients treated at Rambam Medical Center, Israel, between 2013 and 2021. Extracted data included epidemiology, clinical presentation, histological reports, infiltrate clonality status, treatment modalities and response to therapy. The mean follow-up period was 60 months. All patients were diagnosed with stage IA or IB disease. Folliculotropic mycosis fungoides was the most prevalent variant (49%). Most patients were treated with phototherapy (90%), with a response rate of 85%, and a complete response rate of 55% after the first course. There were no significant differences in response to phototherapy between the folliculotropic or other variants (p = 0.072). Similarly, delayed diagnosis, atopic diathesis, clonality, phototherapy type or number of treatments, were not associated with response to therapy, while protracted phototherapy was associated with prolonged remission. In conclusion, mycosis fungoides in the paediatric population is an indolent disease with a favourable prognosis and potentially prolonged response to phototherapy.

A Randomized Double-blind Placebo-controlled Trial of Oral Aspirin for Protection of Melanocytic Nevi Against UV-induced DNA Damage

DNA damage plays a role in ultraviolet (UV)-induced melanoma. We previously showed that aspirin (ASA) can suppress prostaglandin-E2 (PGE2) and protect melanocytes from UV-induced DNA damage in mice, and suggested that taking ASA before acute sun exposure may reduce melanoma risk. We conducted a prospective randomized placebo-controlled trial to determine if orally administered ASA could suppress PGE2 in plasma and nevi and protect nevi from UV-induced DNA damage. After obtaining plasma and determining the minimal erythemal dose (MED) in 95 subjects at increased risk for melanoma, they were randomized to receive a daily dose of placebo, 81 mg ASA, or 325 mg ASA, in double-blind fashion for one month. After this intervention, one nevus was irradiated (dose = 1 or 2 MED) using a solar simulator. One day later, MED was re-determined, a second plasma sample was obtained, and the UV-irradiated nevus and an unirradiated nevus were removed. ASA metabolites were detected in the second plasma sample in subjects in the ASA arms. There were no significant differences in the pre- and post-intervention MED between those patients receiving ASA and placebo. Significantly reduced PGE2 levels were detected in plasma (second vs. first samples) and in nevi (both unirradiated and UV-treated) in subjects receiving ASA compared to placebo. Comparing UV-treated nevi from the ASA and placebo cohorts, however, did not reveal significant reductions in CD3-cell infiltration or 8-oxoguanine and cyclobutane pyrimidine dimers. Thus ASA did not effectively protect nevi from solar-simulated UV-induced inflammation and DNA damage under the conditions examined. PREVENTION RELEVANCE: Despite promising rationale, ASA at conventional dosing was not able to protect nevi against UV-induced DNA damage under the conditions examined.See related Spotlight, p. 71.

Unilesional mycosis fungoides: a case report and review of literature

Mycosis fungoides (MF) is the commonest primary cutaneous T-cell lymphoma (CTCL). Classically MF is presented clinically as multilesional disease but occurrence of solitary lesion, though quite rare, is on the record. This rare variant of MF is clinically and histopathologically indistinguishable from classic MF. Due to the rarity of the presentation the clinician may miss the diagnosis and the pathologist may also be in diagnostic dilemma specially if not clinically oriented. Here we describe a case of unilesional/solitary MF (UMF) in a 59 years old male who was initially clinically diagnosed as inflammatory dermatosis and was treated accordingly without any appreciable clinical response for over 4 years. Unresponsiveness to empirical treatment led to biopsy which finally proved it to be UMF. The clinical, light microscopic and immunohistochemical features of UMF are briefly reviewed to create awareness among the clinicians and pathologists about this rare variant of MF. IMC J Med Sci 2022; 16(1): 006 *Correspondence: Wasim Selimul Haque, Head, Department of Histopathology and Cytopathology, Jaber Al-Ahmed Armed Forces Hospital, Kuwait Armed, Forces, Subhan Cantonment, Kuwait. Email: audrirodelawasim@gmail.com

Diagnosis of Early Mycosis Fungoides

Mycosis fungoides (MF), the most common type of cutaneous T-cell lymphomas, generally has a favorable clinical course. Early MF typically presents erythematous patches and/or plaques and lasts for many years without affecting the life expectancy. Only limited cases progress to develop skin tumors, with subsequent lymph nodes and rarely visceral organ involvement. One of the clinical problems in early MF is the difficulty in differentiating the disease from benign inflammatory disorders (BIDs), such as atopic dermatitis, chronic eczema, and psoriasis. In some MF cases, clinical and pathological findings are similar to those of BIDs. However, the accurate diagnosis of early MF is quite important, as inappropriate treatment including immunosuppressants can cause unfavorable or even fatal outcomes. This article focuses on general methods and novel tools for diagnosis of early MF.

Diagnosis of T-cell lymphoid proliferations of the skin: putting all the pieces together

The spectrum of T-cell lymphoid proliferations of the skin varies from indolent to highly aggressive diseases and therefore an accurate pathological diagnosis is paramount. Integration of clinical, histopathological, immunohistochemical, and molecular findings is of crucial importance in the evaluation of these processes. In this article, we discuss selected situations where difficulty may arise for the pathologist evaluating this type of skin biopsies, such as: the diagnosis of early (patch stage) mycosis fungoides, the distinction of mycosis fungoides with large cell transformation from primary cutaneous anaplastic large cell lymphoma, the recognition of new histopathological patterns of lymphomatoid papulosis and the entities they mimic, the evaluation of primary cutaneous anaplastic large cell lymphoma with expression of markers suggestive of systemic origin (such as ALK), the awareness of the wide range of clinical and pathological presentations of hydroa vacciniforme-like EBV-positive T-cell lymphoproliferative disorders, the evaluation of cases of primary cutaneous γδ T-cell lymphoma showing predominantly epidermotropic pattern of growth, and the correct interpretation of findings seen in indolent proliferations such as primary cutaneous acral CD8-positive T-cell lymphoma and primary cutaneous small/medium size CD4 + T-cell lymphoproliferative disorder.

Mycosis Fungoides: A Clinicopathological Study of 60 Cases from a Tertiary Care Center

Background:

Mycosis fungoides (MF) is the most common primary cutaneous lymphoma. It affects usually the covered areas of the body in elderly males in 6^th and 7^th decades of life. Atypical dermal lymphoid infiltrate is seen along with epidermotropism. Nuclei of neoplastic cells are convoluted. The neoplastic cells demonstrate positivity for CD3 (Pan T) immunohistochemical stain. Majority show increased CD4 to CD8 ratio. The present study was done to study the clinicopathological features, which might be of help in reaching a correct diagnosis in these cases.

Materials and Methods:

A retrospective descriptive study was conducted on 60 reported cases of MF. The retrieved slides were reviewed for clinical and histopathological features and immunohistochemical profile.

Results:

The ages ranged from 20–84 years, mean age was 47 years. Majority (75%) of patients were male. Trunk and extremities were the sites most commonly affected. There was significant inverse correlation between epidermal thickness and tumor stage (P = 0.02). Thickened epidermis was seen in patch stage and thickness reduced with progressing stage. The intensity of dermal infiltrate and cell size was also statistically significantly linked to stage progression (P < 0.001 each). In addition, proliferation index also correlated significantly with tumor stage (P = 0.002).

Conclusion:

Clinical information and histological features are equally important in the accurate diagnosis of MF. Papillary dermal fibrosis is a useful diagnostic clue. CD4:CD8 ratio is not increased in all cases; it may be decreased or remain unchanged.

Follicular Eruption With Folliculotropic Lymphocytic Infiltrates Associated With Iatrogenic Immunosuppression: Report and Study of 3 Cases, and Review of the Literature

BACKGROUND

Several cases of folliculotropic mycosis fungoides, associated with immunosuppressive therapy, including calcineurin inhibitors, have been reported in solid organ transplant patients. We have encountered 3 patients on immunosuppressive therapy who developed follicular eruptions with folliculocentric infiltrates of nonatypical lymphocytes.

OBJECTIVE

To characterize these follicular eruptions and review the literature.

METHODS

Three patients, aged 7-15 years, who were treated with systemic immunosuppressive therapy developed follicular eruptions characterized histopathologically by folliculocentric lymphocytic infiltrates. These were studied clinically, histopathologically, immunophenotypically, and molecularly for T-cell receptor (TCR) gene rearrangement.

RESULTS

All 3 cases were characterized histopathologically by folliculocentric infiltrates of nonatypical CD3 T lymphocytes with variable follicular exocytosis. Two cases also showed follicular mucinosis. Marked reduction in CD7 staining, and marked predominance of CD4 cells over CD8 cells was observed in all 3 cases. The TCR gene rearrangement studies were monoclonal in 2 cases. Oral calcineurin inhibitors (2 cyclosporine A and 1 tacrolimus) were part of the therapeutic regimen in all 3 patients. Their cessation along with local corticosteroid creams in 2 patients, and phototherapy with oral acitretin in one patient, was associated with complete clinical remission.

CONCLUSIONS

Patients undergoing systemic immunosuppressive therapy that includes calcineurin inhibitors might develop follicular eruption with some immunophenotypical variations and a monoclonal TCR gene rearrangement but lack sufficient cytomorphological features of folliculotropic mycosis fungoides. Altering the immunosuppressive agent including calcineurin inhibitors may result in regression of the eruptions.

Follicular eruption with folliculotropic lymphocytic infiltrates associated with anti-tumor necrosis factor alpha therapy: Report and study of 3 cases

BACKGROUND

We have encountered three cases of follicular eruptions with folliculotropic infiltrates of non-atypical lymphocytes associated with anti-tumor necrosis factor alpha (TNF-α) therapy.

METHODS

Three patients aged 15 to 56 years treated with anti-TNF-α therapy (one with adalimumab, and two with infliximab) developed follicular eruptions characterized histopathologically by folliculotropic lymphocytic infiltrates. These were studied clinically, histopathologically, immunophenotypically, and molecularly.

RESULTS

All three cases were characterized histopathologically by folliculotropic cell infiltrates of non-atypical T (CD3+) lymphocytes with variable follicular exocytosis. Marked reduction in CD7 staining and marked predominance of CD4+ cells over CD8+ cells were observed in 1 and 2 cases, respectively. T-cell receptor (TCR) gene rearrangement studies were monoclonal in 1 case. Discontinuation of anti-TNF-α therapy in all three cases, with corticosteroid creams in 1 case, led to complete resolution. Rechallenge with adalimumab in 1 case resulted in exacerbation. Replacement of therapy with non-anti-TNF-α biologic agents in 2 cases was not associated with recurrence.

CONCLUSION

Follicular eruptions with folliculotropic lymphocytic infiltrates associated with anti-TNF-α therapy may show some immunophenotypical variations and/or monoclonal TCR gene rearrangements but lack sufficient cytomorphological features of folliculotropic MF. They may resolve with discontinuation of anti-TNF-α therapy.

Combined BRAF and MEK inhibition with PD-1 blockade immunotherapy in BRAF-mutant melanoma

Oncogene-targeted therapy with B-Raf proto-oncogene (BRAF) and mitogen-activated protein kinase kinase (MEK) inhibitors induces a high initial response rate in patients with BRAF^V600-mutated melanoma, with a median duration of response of approximately 1 year^1-3. Immunotherapy with antibodies to programmed death 1 (PD-1) produces lower response rates but with long response duration. Preclinical models suggest that combining BRAF and MEK inhibitors with PD-1 blockade therapy improves antitumor activity^4-6, which may provide additional treatment options for patients unlikely to have long-lasting responses to either mode of therapy alone. We enrolled 15 patients with BRAF^V600-mutated metastatic melanoma in a first-in-human clinical trial of dabrafenib, trametinib and pembrolizumab ( NCT02130466 ). Eleven patients (73%) experienced grade 3/4 treatment-related adverse events, the most common being elevation of liver function tests and pyrexia, most of which resolved with drug interruption or discontinuation of either the anti-PD-1 antibody or the targeted therapy combination. Eleven patients (73%; 95% confidence interval = 45-92%) had an objective response, and six (40%; 95% confidence interval = 16-68%) continued with a response at a median follow-up of 27 months (range = 10.3-38.4+ months) for all patients. This study suggests that this triple-combined therapy may benefit a subset of patients with BRAF^V600-mutated metastatic melanoma by increasing the frequency of long-lasting antitumor responses.

Immunohistochemistry in Dermatopathology and its Relevance in Clinical Practice

Immunohistochemistry (IHC) is an important diagnostic tool in histopathology. Dermatopathology is a rapidly developing subspecialty of histopathology. Although IHC is not widely used in routine dermatopathology practice, its application is gradually increasing. IHC is used to differentiate two conditions with similar morphology, to confirm a diagnosis as well as to assess prognosis. It is more commonly used for neoplastic conditions like melanocytic, hematolymphoid, and spindle cell tumors, although uses can be very wide. Although IHC can aid in diagnosis, sometimes interpretation can be difficult as there may be overlapping findings. Thus, IHC should not be interpreted in isolation and should be done in the context of clinical and histological findings. In this review, we have discussed the uses of various immunohistochemical markers in dermatopathology in the light of current literature and their clinical relevance.

Conjunctival Involvement of T-Cell Lymphoma in a Patient with Mycosis Fungoides

Background. Ocular involvement in mycosis fungoides (MF) cases occurs in one-third of patients with the eyelid being the most frequent site affected; however, conjunctival involvement is rarely reported. Herein, we report a rare case of conjunctival involvement of MF. Case Presentation. A 66-year-old man who was previously diagnosed with MF in 2010 and was treated presented in 2014 complaining of foreign body sensation and redness in both eyes. Slit lamp examination of both eyes showed erythematous conjunctival growth that extended circumferentially. Physical examination revealed erythematous skin lesions on different body parts. Conjunctival biopsy was performed and revealed a dense, highly polymorphic lymphocytic population. The immunophenotype demonstrated a neoplastic T-cell origin consistent with MF. A diagnosis of conjunctival involvement by MF was made. The conjunctiva was treated with radiotherapy resulting in tumor regression. There were no recurrences at the 6-month follow-up. Conclusion. T-cell lymphoma should be considered in patients with a history of MF presenting with conjunctival and skin lesions.

Immunohistochemistry in dermatopathology

CONTEXT

Immunohistochemistry is not a diagnostic test but a highly valuable tool that requires interpretation within a context.

OBJECTIVE

To review the current status and limitations of immunohistochemistry in dermatopathology.

DATA SOURCES

English-language literature published between 1980 and 2014.

CONCLUSIONS

Although immunohistochemistry is rarely completely specific or sensitive, it is an important adjunctive technique in dermatopathology and can be helpful in a series of diagnostic dilemmas.

Origin Use of CD4, CD8, and CD1a Immunostains in Distinguishing Mycosis Fungoides from its Inflammatory Mimics: A Pilot Study

Patch-stage/early mycosis fungoides (MF) is difficult to differentiate from benign dermatoses, despite several robust histologic criteria. Most studies include advanced lesions and data about early disease is limited.

Objectives:

(1) To compare the CD4:CD8 ratio in patch-stage MF versus inflammatory mimics. (2) To study patterns of CD1a expression in the epidermis and dermis in the two groups.

Materials and Methods:

Twenty cases each of early MF and inflammatory dermatoses were selected. The diagnoses were established after clinicopathologic correlation, repeat biopsies, and follow-up. The inflammatory group included pityriasis lichenoides chronica, actinic reticuloid, lichenoid purpura, and various psoriasiform dermatoses. Immunohistochemistry was done for CD4, CD8, and CD1a. Epidermal CD4, CD8 cells were quantified and CD1a was graded semi-quantitatively in the epidermis and dermis.

Results:

The average CD4:CD8 ratio was 4.2 in MF (range: 1-16.8), and 0.9 in inflammatory diseases (range: 0.43-5), which was statistically significant (P < 0.0001). None of the MF cases had a ratio <1. Four cases of pityriasis lichenoides chronica had a ratio >1. CD1a cells had a continuous or confluent epidermal pattern in almost all cases of MF, while they occurred as small or large groups in the dermis. In inflammatory dermatoses, there were either isolated or scattered CD1a+ cells in both epidermis and dermis.

Conclusions:

Elevated CD4:CD8 ratio favors MF. But there is an overlap in the lower range with pityriasis lichenoides chronica. These cases require good clinicopathologic correlation and follow-up. Patterns of CD1a expression are more reliable. Immunostains buttress morphology and are a valuable addition.

The role of immunohistochemical analysis in the diagnosis of parapsoriasis

Parapsoriasis is a chronic dermatosis whose biological distinction from early mycosis fungoides, the most frequent form of cutaneous T-cell lymphoma, is still not clearly defined. Two types of parapsoriasis have been delineated: large-plaque parapsoriasis and small-plaque parapsoriasis. The lack of clinical and histological features, which may allow distinguishing parapsoriasis from early mycosis fungoides has prompted several investigations to assess the role of immunohistochemistry in establishing a conclusive diagnosis of these conditions. However, the additional data obtained by immunohistochemical analysis concerning the CD4/CD8 ratio, the aberrant expression of T-cell antigens and the expression of proliferation markers has not generally helped establish a more definitive diagnosis. This review critically discusses these immunohistochemical markers and their use in diagnosis of parapsoriasis.

Immunophenotypic correlation between skin biopsy and peripheral blood findings in mycosis fungoides

In mycosis fungoides (MF) with blood involvement, T-cell immunophenotypes in skin and blood have not been compared. Our aim was to evaluate T-cell immunophenotypes in skin by immunohistochemical analysis and compare results with flow cytometric (FC) findings in blood. Of 20 patients with MF with blood involvement, the immunophenotype was discrepant in 11 (55%). Compared with FC findings in blood, immunohistochemical analysis of skin samples failed to detect partial deletion of CD2 (5/11 [45%]), CD3 (3/11 [27%]), and CD5 (3/11 [27%]) and overrepresented deletion of CD7 in 2 (18%) of 11 patients. In addition, CD8+ MF was missed by immunohistochemical analysis in 2 (18%) of 11 patients. Identical T-cell populations were demonstrated by T-cell gene polymerase chain reaction in skin and blood in 8 of the 11 patients who had a discrepant immunophenotype. Awareness of the limitations of immunohistochemical analysis of skin samples is of practical value for pathologists interpreting skin biopsies in MF patients. In addition, our findings suggest CD8+ MF to be more common than previously reported.

Immunocytochemistry and the diagnosis of cutaneous lymphoma

Cutaneous lymphoid infiltrates may pose some of the most difficult diagnostic problems in dermatopathology. Immunocytochemistry is often employed in an effort to determine whether an infiltrate is neoplastic or, in the case of clearly malignant infiltrates, to provide a specific diagnosis. The rarity of these disorders and the variant immunocytochemical profiles they may present further thwart understanding and sometimes prevent an accurate diagnosis. In this review the common immunocytochemical profiles of various cutaneous lymphomas are presented and potential pitfalls and problems considered. Immunocytochemistry is not a diagnostic test but, as in other areas of histopathology, is a highly valuable tool that requires critical interpretation within a context: so applied, it is an indispensable part of the pathologist's arsenal in evaluating lymphoid infiltrates and defining different lymphomas.

The Spectrum of Histopathologic and Immunohistochemical Findings in Folliculotropic Mycosis Fungoides

BACKGROUND

Since the original designation of folliculotropic mycosis fungoides (FMF) as a distinct entity, there has been an increasing appreciation of the broad clinical and histopathologic spectrum with which this disease can present. However, there have been few large histologic studies characterizing the various histopathologic patterns.

OBJECTIVE

In this study, we attempt to describe the histopathologic and immunohistochemical features of 47 biopsy specimens from 34 patients with FMF.

METHODS

We searched our lymphoma database for patients with FMF in which detailed histopathologic information and slides as well as clinical information was available for review. Additionally, immunohistochemical studies for CD4, CD8, and CD1a were performed in all cases in which the block was available.

RESULTS

In addition to the prototypical pattern of a folliculotropic lypmphoid infiltrate with or without mucinosis, the histologic features of follicular mycosis fungoides may include a granulomatous reaction, cystic and comedonal changes, an eosinophilic folliculitis pattern and basaloid folliculolymphoid hyperplasia as well as pustular changes, interface dermatitis and an interstitial dermatitislike pattern. Unlike conventional mycosis fungoides, eosinophils and plasma cells are conspicuous within the accompanying reactive infiltrate. We have also noted an exceedingly high number of Langerhans cells within the follicular epithelium. The CD4:CD8 ratio frequently is 10:1 or greater and the follicles show abundant CD1a positive cells.

CONCLUSIONS

FMF may present with a broad spectrum of histopathologic changes including interstitial, granulomatous, fibrotic and acneiform reactions that may lack the typical histologic attributes of a cutaneous T-cell lymphoma. Recognition of these myriad of histologic presentations can be of great diagnostic utility.

Diagnosis of Mycosis Fungoides

Mycosis fungoides (MF) is the most common form of primary cutaneous T-cell lymphoma. In its early stage it may mimic benign dermatoses both on a clinical and histologic basis. MF usually expresses CD3 and CD4 (T-cell) markers. CD7 is expressed on about 90% of CD4 T cells and is often deficient on malignant T cells. Thus, CD7 may be useful in evaluating the nature of dermal lymphoid infiltrates. The aim of this study was to evaluate the usefulness of immunohistochemical detection of T-cell markers on paraffin-embedded sections, CD3 and CD7 (clone CBC.37), in the differential diagnosis of MF and benign dermatoses. Forty-two patients with diffuse dermal T-lymphocytic infiltrates were selected. Previous clinicopathologic correlation and follow-up had established the diagnosis of MF in 31 patients and benign dermatoses in 11. The mean value of stained cells in MF was 86.45% for CD3 and 53.09% for CD7 (P<0.001); in benign dermatoses it was 79.09% for CD3 and 73.63% for CD7 (P=0.669). CD7 immunolabeling was significantly lower in the MF group (P=0.048). A semiquantitative evaluation revealed a considerable loss of CD7 immunolabeling in comparison with CD3 in patients with MF. The authors conclude that CD7 study may represent a valuable tool in the distinction between inflammation and neoplasia in T-lymphoproliferative skin disorders.

Reassessment of diagnostic criteria in cutaneous lymphocytic infiltrates

CONTEXT

Non-specific lymphocytic infiltrates of the skin pose difficulties in daily practice in pathology. There is still a lack of pathognomonic signs for the differential diagnosis between benign and malignant lymphocytic infiltrates.

OBJECTIVE

To evaluate the morphological and immunohistochemical profile of lymphocytic infiltrations of the skin according to clinical outcome.

TYPE OF STUDY

Retrospective; histopathological and immunohistochemical analysis.

SETTING

Referral center, university hospital.

SAMPLE

28 cases of lymphocytic infiltrates of difficult differential diagnosis selected from the records.

MAIN MEASUREMENTS

Eighteen histological variables and the immunophenotypic profile were assessed using the CD4, CD8, CD3, CD20 and CD30 lymphoid markers and compared to subsequent follow-up.

RESULTS

The most common diagnoses were: initial mycosis fungoides (eight cases) and drug reactions (five cases). Single morphological variables did not discriminate between benign and malignant infiltrates except for the presence of Pautrier-Darier's microabscesses, which were found only in mycosis fungoides (p = 0.015). Patterns of superficial and deep infiltration (p = 0.037) and also the presence of eosinophils (p = 0.0207) were more frequently found in benign lymphocytic infiltrates. Immunohistochemical profile of T-cell subsets showed overlap between benign and malignant infiltrates with a predominance of CD4-positive (helper) lymphocytes in the majority of cases.

CONCLUSIONS

A combination of clinical and histological features remains the most reliable approach for establishing a definite diagnosis in cases of lymphoid skin infiltrates.

Value of the CD8-CD3 ratio for the diagnosis of mycosis fungoides

Histopathological diagnosis of mycosis fungoides is difficult, especially in early lesions that may be indistinguishable from inflammatory dermatoses. Mycosis fungoides is a clonal proliferation of mature epidermotropic CD4+ lymphocytes. The aim of this study was to determine the contribution of the CD8-CD3 ratio to the diagnosis of mycosis fungoides. We retrospectively compared the immunophenotypic characteristics of 30 mycosis fungoides with 28 inflammatory dermatoses. The diagnosis of mycosis fungoides was reinforced in all cases by the presence of a cutaneous dominant T-cell clonal population. To analyze exclusively the lymphocytic infiltrates, CD4, which is also expressed by histiocytes, was not considered. The CD8-CD3 ratio was determined separately in the epidermis and the dermis using two methods, one quantitative and the other semiquantitative. Concordance rates between the two methods were higher in epidermal than dermal infiltrates. The mean CD8-CD3 ratio was significantly lower for mycosis fungoides than control cases, with the difference being greater in the epidermal than the dermal component. Although not absolutely specific, a low CD8-CD3 ratio in the epidermal component of a lymphocytic infiltrate supports the diagnosis of mycosis fungoides. It can be evaluated in routine practice using a semiquantitative approach.

Mycosis fungoides-like reaction in a patient treated with Gleevec

BACKGROUND

Gleevec trade mark is a protein tyrosine kinase inhibitor used in the treatment of chronic myelogenous leukemia and gastrointestinal stromal tumor. Currently, Gleevec is also being used in protocols for treatment of other malignancies such as melanoma. A few, non-descript cutaneous eruptions have been reported in patients receiving Gleevec.

CASE REPORT

A patient with a gastrointestinal stromal tumor developed a centripetal, slightly pruritic, predominantly macular eruption. Histologically, there was a superficial and mid-perivascular cellular infiltrate of hyperchromatic, large lymphocytes with focal epidermotropism, thus resembling mycosis fungoides. The infiltrate was composed predominantly of T cells (CD3), with a 1:1 CD4:CD8 ratio, therefore consistent with a reactive process, i.e. a drug reaction induced by Gleevec.

CONCLUSION

Gleevec should be considered in the differential diagnosis of pseudolymphoma drug eruptions.

Hypopigmented mycosis fungoides: frequent expression of a CD8+ T-cell phenotype

Hypopigmented mycosis fungoides (MF) is a form of cutaneous T-cell lymphoma in which hypopigmentation occurs in the absence of classic lesions of MF. Hypopigmented MF predominantly affects people with dark complexions. The natural history of this variant of cutaneous T-cell lymphoma is similar to that of conventional MF, although the disease onset is usually in childhood or adolescence. In a retrospective study we evaluated the clinical, histopathologic, immunohistochemical, and molecular characteristics of hypopigmented MF in 15 patients. Similar to other reports, the disease onset occurred in childhood and adolescence in most of the cases. The survival rate was comparable with that of classic MF. We did not observe progression to systemic disease or lymph node involvement. Histopathologically hypopigmented lesions were indistinguishable from hyperpigmented or erythematous patches. On immunohistochemical analysis a predominantly CD8+ infiltrate was detected in the majority of cases (nine of 15 patients). To determine whether epidermotropic CD8+ T cells represent the malignant T-cell clone or whether these cells are innocent, tumor-infiltrating T lymphocytes, we performed microdissection of epidermotropic CD8+ T cells and analyzed T-cell receptor-gamma chain gene for rearrangements. The epidermotropic CD8+ T lymphocytes showed clonal T-cell receptor gene rearrangement and therefore represented the malignant T-cell clone. We conclude that hypopigmented MF tends to occur in young people and that it belongs to the group of CD8+ cutaneous T-cell lymphomas in the majority of cases.

Evaluation of a new paraffin-reactive CD7 T-cell deletion marker and a polymerase chain reaction-based T-cell receptor gene rearrangement assay: implications for diagnosis of mycosis fungoides in community clinical practice

BACKGROUND

T-cell deletion and T-cell receptor (TCR) gene rearrangement studies are helpful in the early diagnosis and subsequent management of mycosis fungoides (MF). However, this often requires fresh-frozen tissue that can be difficult to obtain and evaluate in community clinical practice. A new CD7 antibody, the most sensitive and specific T-cell deletion marker, and a new TCR-gamma gene rearrangement polymerase chain reaction (PCR) assay (TCR-gamma PCR) are now available on routine paraffin-embedded biopsy specimens.

OBJECTIVE

Our purpose was to assess the utility of CD7 deletion and TCR-gamma PCR in the diagnosis of MF using routine paraffin-embedded biopsy material.

METHODS

Cases of MF (n = 17) with matching frozen tissue immunohistochemistry and benign reactive dermatoses (lichen planus; n = 27) were assessed for CD7 (Clone: CD7-272) deletion and TCR-gamma PCR using paraffin-embedded biopsy specimens.

RESULTS

Excellent concordance comparing frozen and paraffin embedded CD7 immunostaining (88%) was observed. CD7 deletion and TCR-gamma PCR was sensitive (94%) and specific (96%) for a diagnosis of MF using paraffin-embedded biopsy specimens.

CONCLUSION

In the diagnosis of MF, detection of CD7 deletion and monoclonal TCR rearrangements can be successfully performed in a cost-effective, timely fashion using routine formalin-fixed paraffin-embedded biopsy specimens.

PCR-heteroduplex analysis of T-cell receptor gamma gene rearrangement in paraffin-embedded skin biopsies

We developed a rapid, simple, and sensitive method for the detection of T-cell receptor-gamma (TCRgamma) gene rearrangements in paraffin-embedded skin biopsies. Available techniques often require either fresh tissue, several primer pairs, nested amplifications, or specialized electrophoresis steps such as denaturing gradient gel electrophoresis. Our method is based on heteroduplex analysis of polymerase chain reaction (PCR) products of the TCRgamma in a nondenaturing modified polyacrylamide gel using a single pair of primers and is adapted for paraffin-embedded tissue. When tested against Southern blot analysis, the PCR results correlated in 8 of 9 cases. Six mature cutaneous B-cell lymphomas and 29 inflammatory skin disorders all resulted in a polyclonal amplification pattern. When analyzing 3-mm or 4-mm punch biopsies of 51 cases of cutaneous T-cell lymphoma, 37 (72.5%) showed a clonal rearrangement with this technique. For 7 cases of patch stage mycosis fungoides, frozen tissue and formalin-fixed and paraffin-embedded tissue was available, and in 5 of 7 cases (71%), the results in frozen and paraffin-embedded tissue were concordant. One case showed a clonal pattern in frozen tissue but not in paraffin-embedded tissue, and one case was polyclonal in frozen tissue but monoclonal in paraffin-embedded tissue. Using serial dilutions of DNA from a T-cell ALL in a polyclonal background (tonsil), we established a sensitivity of 0.5%. Heteroduplex PCR of the TCRgamma is a rapid, sensitive, and inexpensive screening procedure as well as a useful adjunct to histologic analysis and immunophenotyping of cutaneous T-cell proliferations.