Cutaneous pseudolymphoma-A review on the spectrum and a proposal for a new classification.

Cutaneous pseudolymphomas (PSLs) belong to a group of lymphocytic infiltrates that histopathologically and/or clinically simulate lymphomas. Different causative agents (e.g., Borrelia sp., injected substances, tattoo, arthropod bite) have been described, but in many cases no cause can be identified, hence the term idiopathic PSL. Clinicopathological correlation is important to make the diagnosis. Four main groups of cutaneous PSL can be distinguished based on histopathologic and/or clinical presentation: (a) nodular PSL; (b) pseudo-mycosis fungoides (pseudo-MF) and simulators of other CTCLs; (c) other PSL (representing distinct clinical entities); and (d) intravascular PSL. This article gives an overview of the histopathologic and clinical characteristics of cutaneous PSLs and proposes a new classification.

Cutaneous Pseudolymphomas. / Pseudolinfomas cutáneos.

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.

Lymphocytic interstitial pneumonia and other benign lymphoid disorders.

Nonneoplastic pulmonary lymphoid disorders consist of a complex spectrum of diseases for pathologists and pulmonologists alike. Advances in our understanding of these disorders in recent years have led to revisions in the classification scheme. This review summarizes the clinicoradiological and pathological features of several benign pulmonary lymphoid disorders as well as the current knowledge regarding their pathogenesis. The disorders discussed include lymphocytic interstitial pneumonitis, follicular bronchiolitis, nodular lymphoid hyperplasia, inflammatory pseudotumor, Castleman disease, immunoglobulin G4-related disease in the lung, and posttransplant lymphoproliferative disease.

A study of histologic and immunophenotypical staining patterns in cutaneous lymphoid hyperplasia.

BACKGROUND: Cutaneous lymphoid hyperplasia (CLH) is generally classified according to clinicopathologic entities or put into broad spectrums of B-cell or T-cell predominance or co-dominance. OBJECTIVE: We sought to discern histologic features and immunohistochemical staining patterns in CLH that may form a basis for a histologic classification system. METHODS: We studied the clinical, histologic, immunophenotypical, and molecular characteristics of 24 consecutive patients with CLH. RESULTS: The 24 cases were classified according to characteristic histologic features and immunophenotypical staining patterns as follows: presence of germinal center (GC) cell clusters forming well-defined lymphoid follicles (n = 10); presence of clusters of GC cell clusters not forming well-defined lymphoid follicles (n = 6); persistent arthropod assault type CLH (n = 1); CLH with a prominent histiocytic component (n = 4); and CLH without specific histologic and immunophenotypical features, that is, nonspecific mixed T-cell and B-cell CLH (n = 3). Most of the CLH cases did not demonstrate clonal T-cell receptor and/or immunoglobulin heavy chain gene rearrangements except for 3 cases in which the long-term follow-up was uneventful. LIMITATIONS: There were a limited number of cases in our study. CONCLUSIONS: A classification based on characteristic histologic features and immunophenotypical staining patterns, along with pertinent clinical and molecular data, may enhance the diagnosis of CLH.

T-cell-rich angiomatoid polypoid pseudolymphoma of the skin: a clinicopathologic study of 17 cases and a proposed nomenclature.

BACKGROUND: We describe a series of previously unreported, distinctive, polypoid solitary T-cell-rich cutaneous pseudolymphomas. METHODS: The clinicopathologic features were examined in 17 cases. RESULTS: Patient ages ranged from 16 to 71 years (mean = 38.5) with a female predominance (female : male = 14 : 3). All lesions, clinically diagnosed most often as pyogenic granuloma, presented as a solitary, polypoid, erythematous, papule ranging in size from 2.5 to 7.5 mm (mean = 5.8). Most occurred on the head and neck (7) and trunk (6) with other sites including the thigh (1), shoulder (1) and knee (1). A dense dermal infiltrate composed of mildly atypical lymphocytes with variable numbers of admixed plasma cells and histiocytes was prototypical. Commonly, there was an associated epidermal collarette (16/17), Grenz zone (11/17) or admixed eosinophils (8/17). Prominent vessels lined by plump endothelial cells, reminiscent of high endothelial venules of lymph nodes, were universal and some degree of telangiectasia was also common (12/17). CD3-positive T-cells consisted of an admixture of CD4-positive and CD8-positive forms (15/16). Multiple studies suggested polyclonality (seven cases). No recurrences after lesional excision were noted in the 17 patients with a follow-up range from 24 to 120 months (mean = 46.6). CONCLUSION: Although these lesions share histopathologic features of the so-called acral pseudolymphomatous angiokeratoma of children (APACHE), they occur in a completely different clinical setting, present in solitary and polypoid fashion and are T-cell rich. We propose the diagnostic label T-cell-rich angiomatoid polypoid pseudolymphoma for this distinctive but presumably reactive lesion.

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.

Prognostic value of cell-cycle markers in ocular adnexal lymphoma: an assessment of 230 cases.

BACKGROUND: To determine the prognostic value of cell-cycle associated markers in ocular adnexal lymphoma (OAL). METHODS: Two hundred sixty-one consecutive cases of ocular adnexal lymphoproliferative lesions were subdivided into reactive lymphoid hyperplasia (RLH), atypical lymphoid hyperplasia (ALH) and OAL. The latter were sub-typed according to the new WHO Lymphoma Classification. All lesions were investigated applying standard immunohistochemical methods with antibodies specific for pRB, p53, p16, p21, BCL-6 and for multiple myeloma oncogene-1-protein (MUM1, also known as IRF4). The main endpoints included the development of a local recurrence, of systemic disease and of lymphoma-related death. The association of prognostic variables with endpoints was assessed by multiple logistic and Cox regression models, respectively. RESULTS: The ocular adnexal lymphoproliferative lesions were categorised as OAL ( n=230; 88%), RLH ( n=29; 11%), and ALH ( n=2; 1%). The major lymphoma subtypes included 136 extranodal marginal zone B-cell lymphoma (EMZL), 31 diffuse large cell B-cell lymphomas, 27 follicular lymphomas, 9 plasmacytomas, 9 lymphoplasmocytic lymphoma/immunocytomas and 8 mantle cell lymphomas. The median follow-up time was 44.5 months. Most OAL patients had Stage IE disease and were treated with radiotherapy. Thirty-seven (25%) Stage IE patients had tumour relapses: these were significantly associated with an increased BCL6 blast percentage. Sixty-two (42%) Stage IE patients developed systemic disease: they had "non-EMZL" with large growth fractions and increased blast percentages for BCL6. Fifty-seven (25%) OAL patients died because of their lymphoma; lymphoma-related death was significantly associated on multivariable analysis with advanced clinical stage, an age >60 years and large tumour growth fractions. CONCLUSION: Subtyping of OAL according to the new WHO Lymphoma Classification, the stage of disease and tumour cell growth fraction aided the prediction of (1) tumour relapse, (2) the development of systemic disease and (3) lymphoma-related death in OAL.

Cutaneous lymphoid hyperplasias.

Benign hyperplastic lymphoid infiltrates of the skin (pseudolymphoma, older term) simulate lymphoma clinically and histologically. They can be divided into B-cell predominant (typical cutaneous lymphoid hyperplasia (CLH), angiolymphoid hyperplasia, Kimura's disease, and Castleman's disease) and T-cell predominant (T-cell CLH, lymphomatoid contact dermatitis, and lymphomatoid drug eruption). Both types may represent exaggerated reactions to diverse external antigens (insect bite, tattoo, zoster, trauma, among others). A composite assessment of clinical presentation and behavior, routine histology, immunophenotyping, and molecular studies is essential for the diagnosis of benign cutaneous lymphoid infiltrates. Treatment includes antibiotics, intralesional and systemic corticosteroids, excision, radiotherapy, and immunosuppressants. Treatment depends on the assessment and biologic behavior, which is usually benign. Molecular biologic analysis has shown that a significant proportion of cases harbor occult B- or T-cell clones (clonal CLH). Progression to overt cutaneous lymphoma has been observed in a minority of cases. Patients with clonal populations of B or T cells and persistent lesions should be closely observed for emergence of a lymphoma.

Controversies in cutaneous lymphomas.

Recently great advances were achieved in the recognition and classification of primary cutaneous lymphomas. With this increased knowledge, one must realize that we must deal with new concepts that are sometimes confusing and controversial. The following controversial subjects are presented in this article: (1) Classification of cutaneous lymphomas; (2) Cutaneous T-cell lymphoma with small/medium-sized pleomorphic cells as a distinct entity; (3) Primary cutaneous follicle center lymphoma and marginal zone lymphoma/ immunocytoma.

Diagnosis and classification of lymphoma based on cytospin preparations: a comparison of hematopathologists and cytopathologists.

The diagnosis of malignant lymphoma based on cytologic preparations is a source of much debate. The purpose of this study was to assess the ability of a number of pathologists to diagnose and classify lymphoma using cytospin preparations, and to compare the rate of agreement between cytopathologists and hematopathologists. One hundred twenty-five cytospins prepared from histologically confirmed hematologic lesions were examined retrospectively and independently by four hematopathologists/fellows and two cytopathologists without knowledge of the final diagnosis; the results were compared with the final diagnoses derived from histology and immunophenotyping. Eighty-one cases were histologically diagnosed as lymphoma (including 67 cases of B-cell non-Hodgkin's lymphoma), and 44 cases represented a reactive process histologically. The distinction of a malignant from a benign process was made in 75% of the cases by cytospin examination, with cytopathologists correctly diagnosing 75% and hematopathologists 76% of the cases. The accuracy rate for subclassification of the lymphoma cases was 49% (46% for cytopathologists, 52% for hematopathologists). The cytopathologists correctly recognized large-cell lymphoma at an increased frequency compared with the hematopathologists (70% vs. 56%, P = 0.11), while the hematopathologists showed a greater ability to recognize and classify nonfollicle center low-grade B-cell lymphomas (57% vs. 28%, P = 0.01). We conclude that cytopathologists and hematopathologists generally achieve similar accuracy rates in the morphologic evaluation of cytologic preparations of lymphoid lesions, though some differences in their performance do exist.

Apoptotic index from fine needle aspiration cytology as a criterion to predict histologic grade of non-Hodgkin's lymphoma.

OBJECTIVE: To investigate whether the assessment of apoptotic index (AI) from fine needle aspiration (FNA) smears of non-Hodgkin's lymphomas (NHL) is reliable and has potential utility as a criterion to predict histologic grade. STUDY DESIGN: AI was independently determined by four cytopathologists as a percentage from routine FNA smears in 96 NHLs and 15 lymphoid hyperplasias. Working formulation (WF) grades from corresponding surgical biopsies were modified to include mantle zone-derived NHLs as intermediate grade and to make diffuse large cell NHL a separate category called "high" grade, whereas WF high grade NHLs were called "very high" grade. Histologic grades were also derived from the Revised European American Lymphoma (REAL) classification. AI was compared with histologic grade using the unpaired, two-tailed Student t test. These data were used to determine potential thresholds for AI that separate lower from higher grade NHLs. RESULTS: Measurements of AI strongly correlated between cytopathologists (median r = .93). Low and intermediate grade NHLs had indistinguishable AIs, whereas higher grade NHLs had significantly higher AIs. Appropriate potential AI thresholds between low or intermediate grade and higher grade NHLs were in the range of 1.5-2.5% (modified WF) and 1-2% (REAL). CONCLUSION: There is excellent interobserver reliability in the measurement of AI from FNAs of NHLs. Higher AIs distinguish higher from lower grade NHLs. Diffuse large cell NHLs had AIs that were similar to WF high grade NHLs.

Lymphoproliferative lesions of the ocular adnexa. Analysis of 112 cases.

OBJECTIVE: Lymphoproliferative lesions of the ocular adnexa were analyzed to examine (1) the suitability of the Revised European-American Lymphoma (REAL) classification for the subtyping of the lymphomas in these sites; (2) the predictive value of the REAL classification for the evolution of these tumors; and (3) the frequency and prognostic impact of tumor type, location, proliferation rate (Ki-67 index), p53, CD5 positivity and the presence of monoclonality within these tumors. DESIGN: Retrospective review. METHODS: The clinical, histomorphologic, immunohistochemical, and molecular biologic (polymerase chain reaction [PCR]) features of lymphoid proliferations of the ocular adnexa were studied. STUDY MATERIALS: The ocular adnexal lymphoproliferative lesions were located as follows: orbit in 52 patients (46%), conjunctiva in 32 patients (29%), eyelid in 23 patients (21%), and caruncle in 5 patients (4%). RESULTS: Reactive lymphoid hyperplasia was diagnosed in 12 cases and lymphoma in 99 cases; 1 case remained indeterminate. The five main subtypes of lymphoma according to the REAL classification were extranodal marginal-zone B-cell lymphoma (64%), follicle center lymphoma (10%), diffuse large cell B-cell lymphoma (9%), plasmacytoma (6%), and lymphoplasmocytic lymphoma (5%). Age, gender, and anatomic localization of the lymphomas did not have prognostic significance during a follow-up period of 6 months to 16.5 years (mean, 3.3 years). Extent of disease at time of presentation was the most important clinical prognostic factor: advanced disease correlated with increased risk ratios of having persistent disease at the final follow-up and with lymphoma-related death (P < 0.001). Histomorphologic features and immunohistochemical markers positively correlating with disseminated disease at presentation, stage at final follow-up, and occurrence of lymphoma-related death included cytologic atypia (P < 0.001), MIB-1 proliferation rate (P < 0.001), and tumor cell p53 positivity (P < 0.001). The MIB-1 proliferation rates greater than 20% in extranodal marginal-zone B-cell lymphoma corresponded to at least stage II lymphoma (P < 0.05). CONCLUSION: The REAL classification is suitable for the subdivision of the ocular adnexal lymphomas. The MIB-1 proliferation rate and p53 positivity may aid the prediction of disease stage and disease progression, whereas PCR can support the diagnosis and reduce the number of histologically indeterminate lesions.