Pseudolymphomatous folliculitis: a clinicopathologic study of 15 cases of cutaneous pseudolymphoma with follicular invasion

Dermatological Considerations in the Diagnosis and Treatment of Marginal Zone Lymphomas

Primary cutaneous marginal zone lymphoma (PC-MZL) is a B-cell lymphoma arising in the skin. Although it is a rare disease, PC-MZL accounts for 20–40% of all primary cutaneous B-cell lymphoma in Western Countries. The aetiology and the pathogenesis of PC-MZL are poorly understood, as it generally lacks the chromosomal translocations most typically present in marginal zone lymphomas of other sites. The diagnosis of PC-MZL may be challenging, due to the rarity of the disease, and needs the competence of different professional figures, including the dermatologist and the pathologist. Furthermore, the management of the patient after the diagnosis is complex and involves the dermatologist, the haematologist, the surgeon, the radiotherapist and the radiologist. The aim of this review is to describe the clinical and histological findings for the diagnosis of PC-MZL, and the state of art for the management of the patient.

Distribution of CD1a-positive cells is not different between pseudolymphomatous folliculitis and primary cutaneous marginal zone lymphoma

Pseudolymphomatous folliculitis (PLF) is a subtype of cutaneous pseudolymphoma that is recognized as an independent disease. PLF is characterized by dermal lymphocytic infiltration surrounding an irregular hyperplastic pilosebaceous unit (i.e., activated pilosebaceous unit). An interstitial distribution of CD1a-positive cells is regarded as an important feature of PLF, especially in distinguishing it from primary cutaneous marginal zone lymphoma (PCMZL), which is associated with a peripheral concentration of CD1a-positive cells. We undertook a clinicopathological investigation of PLF, with a reassessment of CD1a immunohistochemistry. We defined diagnostic criteria for PLF based on past studies and consequently identified 79 cases. In addition, we collected 32 cases of PCMZL and performed detailed clinical, pathological, and immunohistochemical investigations using antibodies to CD3, CD20, and CD1a. We found an interstitial concentration of CD1a-positive cells in 90.2% of PLF and 34.5% of PCMZL cases. The peripheral concentration of CD1a-positive cells was seen in 9.8% of PLF and 34.5% of PCMZL cases. In both diseases, CD1a-positive cells appeared in T-cell nests (88.5% in PLF and 92.9% in PCMZL) but were absent in B-cell nests (0% in both groups). All 79 cases of PLF showed activated pilosebaceous units while 22 of the 32 PCMZL cases displayed pilosebaceous units, although none of these were activated. In summary, regarding the distribution patterns of CD1a-positive cells as a diagnostic feature in distinguishing between PLF and PCMZL is somewhat inconclusive. To differentiate PLF and PCMZL, determining the presence or absence of activated pilosebaceous units is essential.

Cutaneous Pseudolymphoma

The term, cutaneous pseudolymphoma (PSL), refers to a group of lymphocyte-rich infiltrates, which either clinically and/or histologically simulate cutaneous lymphomas. Clinicopathologic correlation is essential to achieve the final diagnosis in cutaneous PSL and to differentiate it from cutaneous lymphomas. A wide range of causative agents (eg, Borrelia, injections, tattoo, and arthropod bite) has been described. Based on clinical and/or histologic presentation, 4 main groups of cutaneous PSL can be distinguished: (1) nodular PSL, (2) pseudo-mycosis fungoides, (3) other PSLs (representing distinct clinical entities), and (4) intravascular PSL. The article gives an overview of the clinical and histologic characteristics of cutaneous PSLs.

Inflammatory features of frontal fibrosing alopecia

INTRODUCTION

Frontal fibrosing alopecia (FFA) is a cicatricial alopecia typically occurring in postmenopausal women. The etiology and pathophysiology of FFA is poorly understood but thought to be immune mediated. This study aims to further explore the extent of fibrosis and the inflammatory microenvironment by characterizing Langerhans cells (LCs), helper T cells, cytotoxic T cells and B cells near hair follicles in FFA.

METHODS

Eleven paraffin-embedded tissues from patients with a clinical and histopathologic diagnosis of FFA were selected for immunohistochemical studies using CD3, CD4, CD8, CD1a and CD20. The lymphocytes and LCs were counted around involved follicles. The CD4/CD8 T-lymphocyte ratios were calculated and compared to the CD4/CD8 T-lymphocyte ratios in uninvolved areas.

RESULTS

On histopathologic review, at least 35% of follicles in each case were affected by the disease with concentric perifollicular fibrosis and a perifollicular lichenoid lymphocytic infiltrate around the infundibuloisthmic portion of the hair follicle. There was an increase of perifollicular LCs (mean of 18, SD of 5.5) and intrafollicular LCs (mean of 14, SD of 4.3) in involved follicles compared to uninvolved follicles (P < .0001). The involved follicles also showed a relative decrease in the CD4/CD8 ratio indicating increased numbers of CD8+ T cells; a finding distinct from the CD4-predominant population in uninvolved follicles (P < .0001).

CONCLUSION

The inflammatory features of FFA show a CD8-biased T-cell infiltrate with increased numbers of LCs in the infundibuloisthmic region. The increased LCs may represent an aberrant immune reaction promoting a CD8+ T-cell response.

Approach to Cutaneous Lymphoid Infiltrates: When to Consider Lymphoma?

Cutaneous lymphoid infiltrates (CLIs) are common in routine dermatopathology. However, differentiating a reactive CLI from a malignant lymphocytic infiltrate is often a significant challenge since many inflammatory dermatoses can clinically and/or histopathologically mimic cutaneous lymphomas, coined pseudolymphomas. We conducted a literature review from 1966 to July 1, 2015, at PubMed.gov using the search terms: Cutaneous lymphoma, cutaneous pseudolymphoma, cutaneous lymphoid hyperplasia, simulants/mimics/imitators of cutaneous lymphomas, and cutaneous lymphoid infiltrates. The diagnostic approach to CLIs and the most common differential imitators of lymphoma is discussed herein based on six predominant morphologic and immunophenotypic, histopathologic patterns: (1) Superficial dermal T-cell infiltrates (2) superficial and deep dermal perivascular and/or nodular natural killer/T-cell infiltrates (3) pan-dermal diffuse T-cell infiltrates (4) panniculitic T-cell infiltrates (5) small cell predominant B-cell infiltrates, and (6) large-cell predominant B-cell infiltrates. Since no single histopathological feature is sufficient to discern between a benign and a malignant CLI, the overall balance of clinical, histopathological, immunophenotypic, and molecular features should be considered carefully to establish a diagnosis. Despite advances in ancillary studies such as immunohistochemistry and molecular clonality, these studies often display specificity and sensitivity limitations. Therefore, proper clinicopathological correlation still remains the gold standard for the precise diagnosis of CLIs.

Cutaneous Pseudolymphomas

The term cutaneous pseudolymphoma refers to benign reactive lymphoid proliferations in the skin that simulate cutaneous lymphomas. It is a purely descriptive term that encompasses various reactive conditions with a varied etiology, pathogenesis, clinical presentation, histology, and behavior. We present a review of the different types of cutaneous pseudolymphoma. To reach a correct diagnosis, it is necessary to contrast clinical, histologic, immunophenotypic, and molecular findings. Even with these data, in some cases only the clinical course will confirm the diagnosis, making follow-up essential.

Multiple nodules on the left cheek represented pseudolymphomatous folliculitis

Pseudolymphomatous folliculitis (PLF) is a rare lesion. Sometimes, the clinical appearance is characterized by multiple large, firm violaceous nodules. In cases with multiple lesions, such biopsy should be performed on one lesion, and once PLF is determined, monitoring for the remained tumor is considered to be the best treatment.

PD-1, S-100 and CD1a expression in pseudolymphomatous folliculitis, primary cutaneous marginal zone B-cell lymphoma (MALT lymphoma) and cutaneous lymphoid hyperplasia

BACKGROUND

Pseudolymphomatous folliculitis is a lymphoid proliferation that clinically and histopathologically mimics primary cutaneous extranodal marginal zone lymphoma of mucosa-associated lymphoid tissue (MALT lymphoma). In this study, we assessed the diagnostic value of three immunohistochemical markers, programmed death-1 (PD-1), CD1a and S100.

METHODS

We evaluated 25 cases of cutaneous lymphoid proliferations with established diagnoses, including 9 patients with pseudolymphomatous folliculitis, 11 with MALT lymphoma, and 5 with cutaneous lymphoid hyperplasia (CLH). The clinical, histopathologic and immunohistochemical characteristics were reviewed and three major characteristics assessed: (a) proportion of T cells expressing PD-1, (b) pattern of expression of CD1a by dendritic cells and (c) pattern of expression of S100 by dendritic cells.

RESULTS

We found pseudolymphomatous folliculitis to have a significant increase in PD-1+ T cells compared with MALT lymphoma (p < 0.0001). The pattern of CD1a staining is also informative: MALT lymphoma is significantly more likely to demonstrate a peripheral concentration of CD1a+ dendritic cells around lymphoid nodules than pseudolymphomatous folliculitis (p < 0.0003) or CLH (p < 0.05). Pseudolymphomatous folliculitis demonstrates an interstitial distribution of CD1a+ cells more often than MALT lymphoma (p < 0.04). S100 staining was not a helpful discriminator.

CONCLUSIONS

Histopathologic factors including PD-1 and CD1a staining patterns may allow for more certainty in distinguishing lymphoid hyperplasia, including pseudolymphomatous folliculitis, from MALT lymphoma.

Clinicopathologic Study of Cutaneous Pseudolymphomas

A study was conducted to determine the clinical and histopathologic findings of cutaneous pseudolymphomas. In the period between July of 1989 and December of 2002, 42 cases were collected. Clinical records and pathology slides of the patients were reviewed retrospectively. A striking common clinical feature was a pruritic papule, nodule, or plaque with a smooth surface on the head and neck. The histologic patterns were diverse, MF-like, perivascular/periadnexal, nodular, diffuse, pseudolymphomatous folliculitis, and acral pseudolymphomatous angiokeratoma of children (APACHE) patterns. The most common pattern was a multinodular pattern with an extension into the deep dermis and subcutaneous adipose tissue. The differentiation between cutaneous lymphomas and pseudolymphomas must depend on a constellation of criteria, never on a single criterion.

Pseudolymphomatous folliculitis: a distinctive cutaneous lymphoid hyperplasia

Pseudolymphomatous folliculitis (PLF) was first described in 1986 as a distinct variant of pseudolymphoma, characterized by a dense lymphoid infiltrate and accompanied by hyperplastic hair follicles. Here in we report a case of PLF presenting as an erythematous plaque with pustules and satellite lesions on forehead in an otherwise healthy adult male patient.

Dermoscopy findings of pseudolymphomatous folliculitis

Pseudolymphomatous folliculitis (PLF), which clinically mimicks cutaneous lymphoma, is a rare manifestation of cutaneous pseudolymphoma and cutaneous lymphoid hyperplasia. Here, we report on a 45-year-old Japanese woman with PLF. Dermoscopy findings revealed prominent arborizing vessels with small perifollicular and follicular yellowish spots and follicular red dots. A biopsy specimen also revealed dense lymphocytes, especially CD1a+ cells, infiltrated around the hair follicles. Without any additional treatment, the patient's nodule rapidly decreased. The presented case suggests that typical dermoscopy findings could be a possible supportive tool for the diagnosis of PLF.

Pseudolymphomatous folliculitis on the nose

Pseudolymphomatous folliculitis (PLF), which sometimes mimicks cutaneous lymphoma, is a rare manifestation of cutaneous pseudolymphoma and cutaneous lymphoid hyperplasia. We describe a 57-year-old Japanese woman with PLF on the nose that resembled cutaneous lymphoma clinically. The biopsy specimen revealed dense lymphocytes, especially CD1a+ cells, infiltrated around the hair follicles. Without any additional treatment, her nodule rapidly decreased before we performed a second biopsy for analysis of the clonal gene rearrangement. Though PLF typically behaves as benign lymphohyperplasia, differentiation from cutaneous lymphoma is necessary.

Primary Cutaneous Folliculotropic and Lymphohistiocytic Anaplastic Large Cell Lymphoma

Background:

Primary cutaneous anaplastic large cell lymphoma (PC-ALCL) is a T-cell lymphoma that presents in the skin and consists of CD30+ anaplastic large lymphocytes with abundant cytoplasm and pleomorphic nuclei. In addition to the classic variant, several other histologic patterns of ALCL have been identified, among them the lymphohistiocytic variant.

Objective and Methods:

We describe a case of the lymphohistiocytic variant of PC-ALCL with a marked follicular involvement. The lesion appeared as a single nodule in the face that completely regressed following biopsy. A diffuse infiltration of lymphocytes and macrophages was seen in the dermis associated with hypertrophied hair follicles, follicular mucinosis, and marked folliculotropism, leading to follicular disruption. Cohesive groups of CD30+ large, atypical lymphocytes with a high proliferative index were seen focally. The patient was followed up for 41 months, during which time no relapses occurred.

Conclusions:

This case shows that PC-ALCL may present with different histologic features, including a follicular variant, that may mimic both benign and malignant conditions.

Primary cutaneous CD4+ small-/medium-sized pleomorphic T-cell lymphoma: a cutaneous nodular proliferation of pleomorphic T lymphocytes of undetermined significance? A study of 136 cases

Patients with skin nodules characterized by the infiltrate of pleomorphic small/medium T lymphocytes are currently classified as "primary cutaneous CD4+ small-/medium-sized pleomorphic T-cell lymphoma" (SMPTCL) or as T-cell pseudolymphoma. The distinction is often arbitrary, and patients with similar clinicopathologic features have been included in both groups. We studied 136 patients (male:female = 1:1; median age: 53 years, age range: 3-90 years) with cutaneous lesions that could be classified as small-/medium-sized pleomorphic T-cell lymphoma according to current diagnostic criteria. All but 3 patients presented with solitary nodules located mostly on the head and neck area (75%). Histopathologic features were characterized by nonepidermotropic, nodular, or diffuse infiltrates of small- to medium-sized pleomorphic T lymphocytes. A monoclonal rearrangement of the T-cell receptor-gamma gene was found in 60% of tested cases. Follow-up data available for 45 patients revealed that 41 of them were alive without lymphoma after a median time of 63 months (range: 1-357 months), whereas 4 were alive with cutaneous disease (range: 2-16 months). The incongruity between the indolent clinical course and the worrying histopathologic and molecular features poses difficulties in classifying these cases unambiguously as benign or malignant, and it may be better to refer to them with a descriptive term such as "cutaneous nodular proliferation of pleomorphic T lymphocytes of undetermined significance," rather than forcing them into one or the other category. On the other hand, irrespective of the name given to these equivocal cutaneous lymphoid proliferations, published data support a nonaggressive therapeutic strategy, particularly for patients presenting with solitary lesions.

Follicular mycosis fungoides - A report of four Indian cases

BACKGROUND

Follicular Mycosis Fungoides (FMF) is an under-recognized disease in India. Its clinical mimics include Hansen's disease and Sarcoidosis.

AIMS

To describe the clinical and pathological features of FMF.

MATERIALS AND METHODS

All cases of FMF between January and December 2007 were retrieved. Cases of conventional epidermotropic MF with a minor follicular component were excluded. Slides were reviewed by two observers. The following criteria were assessed: degree and density of folliculotropism of lymphocytes, location of folliculotropism (infundibular / isthmic / bulbar), follicular mucin, eosinophils, granulomas, and conventional epidermotropism. Each feature was assigned a semi-quantitative grade.

RESULTS

There were four cases of FMF, with an equal gender distribution and a mean age of 17.5 years. All lesions were on the face. They presented as: hypopigmented patches (2) and erythematous plaques (2). Alopecia was seen in two cases. The clinical diagnosis was Hansen's disease in all four, with a differential of Alopecia mucinosa / Sarcoidosis in two cases.The histological features seen were: disproportionate folliculotropism, lymphocyte tagging with haloes, follicular mucin, and nucleomegaly / convolution in all four cases, prominent eosinophils (2), epithelioid granulomas (1), eccrine infiltration (4), parakeratosis at the follicular ostia (2), and sebaceotropism (1). The infiltrate was bulbar (4) and isthmic (2). The rest of the epidermis showed no hint of conventional MF.

CONCLUSION

The preferential features for FMF were involvement of face, dominant folliculotropism, nuclear atypia and convolution, and follicular mucin. Presence of granulomas and eosinophils necessitated exclusion of infectious causes. The absence of findings of MF in the rest of the epidermis should not deter pathologists from rendering this diagnosis.

A case of recurrent pseudolymphomatous folliculitis: A mimic of cutaneous lymphoma

Pseudolymphomatous folliculitis is a rare entity. We present a 62-year-old man with a recurrent solitary nodule on his nose requiring multiple excisions. Microscopic examination of the excisions showed a dense lymphocytic infiltrate containing numerous histiocytes and S100+, CD1a+ dendritic cells that surrounded and infiltrated hypertrophic hair follicles. Diffuse sheets of CD3+ T cells and nodular clusters of CD20+ B cells were also seen. There was normal reactive pattern of follicular centers. Light chain restriction was not detected. T-cell receptor and immunoglobulin heavy chain gene rearrangements by polymerase chain reaction revealed negative findings. A diagnosis of pseudolymphomatous folliculitis was made based on the hypertrophic hair follicles, periadnexal S100+ and CD1a+ dendritic cells, and negative clonal gene rearrangement study findings. This case of recurrent pseudolymphomatous folliculitis is instructive because of the resemblance to cutaneous lymphomas and cutaneous lymphoid hyperplasias, and the need for correct diagnosis to avoid overtreatment of this indolent condition.

Cutaneous pseudolymphoma: an unusual presentation of a scalp mass

The term cutaneous pseudolymphoma (CPL), an accumulation of lymphocytes in response to a foreign antigen or unknown stimuli lacks specificity, and has been used when neither cause nor mechanism for the lymphocytic proliferation has been identified. Cases of childhood CPL are rare and require extensive investigation because of their potential for malignant transformation. We report a case of a child with a scalp mass diagnosed as CPL.

CD1a expression in PEComas

According to the World Health Organization classification, neoplasms with perivascular epithelioid cell differentiation (PEComas) are mesenchymal tumors composed of histologically and immunohistochemically distinctive PEC. Generally, nearly all PEComas have immunoreactivity for both melanocytic (HMB-45 and/or melan A) and smooth muscle (actin (SMA) and/or desmin) markers. Recently the authors reported that benign clear cell sugar tumor of the lung, one of the PEComas, expressed CD1a. Therefore the purpose of the present study was to investigate the relationship between PEComas and CD1a expression. Nineteen PEComas were obtained, which included angiomyolipoma of the kidney or liver, lymphangiomyomatosis of the uterus or lung and clear cell sugar tumor of the lung. Eighteen tumors had alpha-SMA and HMB-45 expression and 16 had melan A expression. In contrast, all 19 tumors had CD1a expression. The present study confirms CD1a expression in many cases of PEComa. These data suggest that CD1a expression can be an additional new marker for PEComas and also supports the distinct and integrated disease entity of PEComas.

The solitary lymphomatous papule, nodule, or tumor

BACKGROUND

Lymphoma and reactive lymphoid infiltrates presenting as solitary lesion pose a diagnostic and prognostic dilemma for the clinician.

OBJECTIVE

We sought to review prognosis and treatment of suggestive solitary lymphoma lesions.

METHODS

A retrospective chart review was conducted in 27 patients who presented with a single solitary lesion suggestive of lymphoma at a cancer center.

RESULTS

Eighteen of 27 patients' (66.7%) lesions were diagnosed as lymphoma by histology and the remainder was classified as reactive lymphoid infiltrates. Only one patient's lymphoma was systemic at presentation and one progressed later. In all, 23 patients (85.2%) subsequently experienced prolonged, complete remissions. The treatments used varied from none or conservative to chemotherapy, with the more aggressive treatments directed especially against lymphomas or recurrent diseases.

LIMITATIONS

This study is limited by the number of patients and follow-up duration (average 36.8 months, range 3-133 months).

CONCLUSION

Patients presenting with a solitary lesion suggestive of lymphoma and negative staging work-up results generally have a good prognosis. Excellent prognosis is usually expected for benign lesions.

A review of 55 cases of cutaneous lymphoid hyperplasia: reassessment of the histopathologic findings leading to reclassification of 4 lesions as cutaneous marginal zone lymphoma and 19 as pseudolymphomatous folliculitis

To clarify the confusion surrounding the diagnosis of cutaneous lymphoid hyperplasia (CLH) that was formerly described as lymphadenosis benigna cutis, lymphocytoma cutis, or lymphocytic infiltration of Jessner and to assess whether newly recognized diagnoses, such as cutaneous marginal zone lymphoma and pseudolymphomatous folliculitis (PLF), may have been overlooked, we reexamined 55 Japanese cases of nonepidermotropic lymphoproliferative disorder that had previously been diagnosed as "cutaneous pseudolymphoma." In all these cases, the immunohistochemical expressions of CD1a, CD3, CD4, CD8, CD20, CD21, CD30, CD43, CD56, CD68, CD79a, kappa and lambda chains, S-100 protein, and latent membrane protein were assessed. In addition, in 13 cases the gene rearrangement of the immunoglobulin heavy chain was investigated using a polymerase chain reaction method. As a result of these investigations, we have identified 4 cases of cutaneous marginal zone lymphoma, 19 cases of PLF, 1 case of diffuse large B-cell lymphoma, and 2 cases of solitary nonepidermotropic pseudo-T-cell lymphoma, with the remaining 29 cases being CLH. Cutaneous marginal zone lymphoma, which represented 7.3% of the total, was distinguished from CLH by the presence of patchy or diffuse proliferation of centrocyte-like cells, plasma cells at the periphery of the lymphocytic infiltration, monotypic restriction of the light chains, and gene rearrangement of the immunoglobulin heavy chain. Pseudolymphomatous folliculitis was identified by the presence of activated pilosebaceous units with abundant CD1a-and S-100 protein-positive T-cell-activated dendritic cells. Of the cases that were reassessed, 34.5% were PLF.

CD1a expression by Barrett's metaplasia of gastric type may help to predict its evolution towards cancer

As emerging in the recent literature, CD1a has been regarded as a molecule whose expression may reflect tumour evolution. The aim of the present work was to investigate the expression of CD1a in a series of Barrett's metaplasia (BM), gastric type (GTBM), with and without follow-up, in order to analyse whether its expression may help to diagnose this disease and to address the outcome. Indeed, GTBM may be confused sometimes with islets of ectopic gastric mucosa and its evolution towards dysplasia (Dy) or carcinoma (Ca) could not be foreseen. We showed a significant higher expression of CD1a in GTBM than in both Dy and Ca; nevertheless, the number of positive GTBM was significantly lower in the group of cases that at follow-up underwent Dy or Ca. Our data address that CD1a may be a novel biomarker for BM and that its expression may help to predict the prognosis of this pathology.

[Pseudolymphomatous folliculitis]

INTRODUCTION

A case of a rare variety of cutaneous pseudo-lymphoma is reported.

CASE REPORT

A 13 Year-old boy presented with a nodule on the nose groove which corresponded histologically to a dense, peri follicular lymphocyte infiltration penetrating the hair. Following partial biopsy, the lesion disappeared within a fortnight.

COMMENTS

Our case report corresponds to the entity described in 1999 in the Japanese. Our case occurred in a Caucasian French adolescent. The papulonodule, usually unique, is composed histologically of a dense, peripilary infiltrate that penetrates and disrupt the hair. The majority of cases have been removed surgically. Those that have not usually disappear following partial biopsy. The individualization of this entity is debatable: the involvement of the hair follicles by the infiltration of pseudolymphomas on the face is frequent and non-specific.

Follicular mycosis fungoides. A histopathologic analysis of nine cases

BACKGROUND

The spectrum of mycosis fungoides is exceedingly broad. Many different variants have been described, based on both clinical appearance and histological pattern. A rare form which shows preferential infiltration of hair follicles by malignant lymphocytes is follicular mycosis fungoides.

METHODS

We reviewed our experience with nine cases of follicular mycosis fungoides.

RESULTS

The unifying feature was infiltration of the hair follicle epithelium by atypical lymphocytes causing varying degrees of damage to the hair follicles. In some specimens the lymphocytes displayed only minor atypia leading to a misinterpretation as pseudolymphoma. Gene rearrangement studies were particularly helpful for establishing a diagnosis of malignant lymphoma. Additionally, epidermotropism of lymphocytes, eosinophils and mucin deposition were present to varying degrees. Mucin makes the distinction from mycosis fungoides-associated follicular mucinosis difficult. We found both dermal mucin and a follicular mucinosis pattern present at different stages of disease in the same patient.

CONCLUSIONS

We suggest the term mycosis fungoides-associated follicular mucinosis should be replaced by follicular mycosis fungoides in future lymphoma classification schemes.