Controversies in mycosis fungoides

From Molecules to Microbes: Tracing Cutaneous T-Cell Lymphoma Pathogenesis through Malignant Inflammation

The etiology of CTCL is a subject of extensive investigation. Researchers have explored links between CTCL and environmental chemical exposures, such as aromatic hydrocarbons (eg, pesticides and benzene), as well as infectious factors, including various viruses (eg, human T-lymphotropic virus [HTLV]-I and HTLV-II) and bacteria (eg, Staphylococcus aureus). There has been growing emphasis on the role of malignant inflammation in CTCL development. In this review, we synthesize studies of environmental and infectious exposures, along with research on the aryl hydrocarbon receptor and the involvement of pathogens in disease etiology, providing insight into the pathogenesis of CTCL.

Clusters, crop dusters, and myth busters: a scoping review of environmental exposures and cutaneous T-cell lymphoma

INTRODUCTION

Cutaneous T-cell lymphoma (CTCL) is a heterogenous group of non-Hodgkin lymphomas. Similar presentation to benign conditions, significant genetic variation, and lack of definitive biomarkers contributes to diagnostic delay. The etiology of CTCL is unknown, and environmental exposures, such as geographic, occupational, chemicals, sunlight, and insects have been investigated.

EVIDENCE ACQUISITION

Review of the literature for CTCL and exposures was performed in PubMed and Google Scholar in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-analyses (PRISMA) Extension for Scoping Reviews. This search yielded 193 total results, which were initially screened with defined inclusion and exclusion criteria. The 45 remaining articles were reviewed and classified by exposure type.

EVIDENCE SYNTHESIS

The most frequently investigated CTCL exposure type was geographic (13/45 articles, 29%). Chemical exposures were commonly discussed (10/45 articles, 22%), along with occupational (10/45 articles, 22%). Insect exposures (6/45, 13%) and sun exposure (3/45, 7%) were also reviewed, along with articles describing multiple exposure types (3/45, 7%). Article types ranged from cases to systematic reviews and case-control studies. Evidence linking CTCL and these exposures was mixed. Limitations of this investigation include reliance on patient reporting and frequent speculation on disease association versus causality.

CONCLUSIONS

This investigation synthesizes the current literature on exposures potentially implicated in the pathogenesis of CTCL, while offering guidance on patient history-taking to ensure potential exposures are captured. Awareness of these possible associations may improve understanding of disease pathogenesis and diagnosis. Moreover, these insights may help with public health decision-making and disease mitigation.

A multidisciplinary approach to the diagnosis of cutaneous T-cell lymphomas

The cutaneous T-cell lymphomas (CTCLs) comprise a spectrum of non-Hodgkin lymphomas with a predilection for the skin. This heterogeneous group of CTCLs include the prototypic CTCL mycosis fungoides (MF) and the recently described Ki-1+ lymphomas. MF is notoriously difficult to diagnose in its early stages. The histologic appearance of early MF is indistinguishable from that of chronic dermatitis. The limitations of light microscopy in the diagnosis of the CTCLs have led to the development of other diagnostic laboratory techniques. The best approach to the diagnosis of the CTCLs is a multidisciplinary one and should include ultrastructural morphometry, immunophenotyping, immunogenotyping, and histologic evaluation whenever possible. It is the purpose of this overview to point out the strengths and weaknesses of each of these techniques and, together with clinical input, to provide a comprehensive and rational approach to patient care.

Epidermal Langerhans' cell densities influence survival in mycosis fungoides and Sézary syndrome

Because Langerhans' cells (LC) (CD1a-positive epidermal cells) have been discussed to be involved in the pathogenesis of mycosis fungoides and Sézary syndrome, the authors examined the influence of densities of Langerhans' cells and, concurrently, of other phenotypes retrospectively on survival of 35 patients. Cell densities were assessed on cryostat sections (alkaline phosphatase antialkaline phosphatase-technique) of the respective diagnostic biopsy specimens. Additionally, two clinical parameters (age, stage of disease) were evaluated. CD1a-positive epidermal cells were demonstrated to be the only cell population being significantly associated (P = 0.011) with survival. Death resulting from mycosis fungoides and Sézary syndrome was significantly (P = 0.003) less frequent in patients with epidermal CD1a-positive cell densities higher than 90 cells/mm2 (optimal break point) as compared with patients with lower numbers. These results suggest that Langerhans' cells have a significant impact on prognosis of patients with mycosis fungoides and Sézary syndrome. They play an important role in the host defense mechanisms against these lymphomas rather than to favor their progression as proposed recently.

Unilesional mycosis fungoides: clinical, microscopic and immunophenotypic features

Seven cases are reviewed in which the histologic and immunohistologic features were those of mycosis fungoides, although the patients presented with solitary lesions which did not recur after local therapy (excision in six, radiotherapy in one), with follow-up of 10 months to 18 years. Immunophenotypic staining of paraffin-embedded tissue revealed a predominant T-lymphocyte proliferation in all cases, None of the four cases studied for BER-H2(Ki-1) were positive, in contrast to the "activated" types of spontaneously regressing lymphoid lesion, lymphomatoid papulosis and "Ki-1" lymphoma. Electron microscopy in one case demonstrated the highly convoluted nuclei of the T cells within the infiltrate. These seven cases represent examples of unilesional mycosis fungoides in which the disease has not recurred after therapy, despite features indistinguishable from those of typical generalised mycosis fungoides-type of cutaneous T-cell lymphoma.

DNA analysis by flow cytometry in cutaneous T-cell lymphomas

DNA histograms of skin and blood specimens from 64 patients with known or suspected cutaneous T-cell lymphoma (CTCL) have been examined and compared with normal blood mononuclear cells and skin biopsy samples from 50 patients with various benign cutaneous conditions (i.e. patch test infiltrates, eczema, psoriasis, lichen planus, atopic dermatitis) in an attempt to establish whether DNA measurements by flow cytometry may improve the early recognition of CTCL. The results indicate that right-skewed G0/G1 peaks are seen frequently in both benign disorders and known and suspected CTCL. Such peaks may reflect increased stainability of DNA due to chromatin dispersion during cell activation and/or cell proliferation and do not constitute reliable evidence of malignancy. In contrast, discrete aneuploid DNA peaks are confined to malignant lesions, but are seen almost exclusively in the advanced stages in which the diagnosis can be established easily based on routine histological criteria. These data indicate that DNA measurements by flow cytometry is of only limited help in the early recognition of CTCL and support the view that the lymphoid infiltrate in early CTCL may be reactive (rather than neoplastic) or alternatively may contain only minor reactive (rather than neoplastic) or alternatively may contain only minor populations of abnormal (malignant) cells which cannot be detected by currently available DNA measurement techniques.

Peripheral neuropathy associated with mycosis fungoides

A 56 year old man with acute sensory-motor polyneuropathy associated with mycosis fungoides is described. EMG studies showed diffuse signs of muscle denervation. A skin biopsy specimen showed a lymphocyte infiltration in the dermis, composed of mycosis cells characterised by deep invaginations of the nuclear membrane, and small Pautrier's microabscesses in the epidermis. Sural nerve biopsy revealed endoneurial fibrosis, a decreased number of myelinated fibres and acute axonal degeneration.

Role of Langerhans cells in epidermotropism of T cells

Certain T lymphocytes display a specific affinity for the epidermis (epidermotropism). Recent studies have suggested that Ia+ Langerhans cells (LCs) are possible targets for the epidermotropism. A variety of self-Ia-reactive cloned T cells were tested for their ability to migrate into the epidermis following intradermal inoculation into the footpads of syngeneic mice. Clone BB5 was chosen as representative of the epidermotropic T cells. We investigated whether the depletion of Ia+ LCs from the epidermis by tape-stripping could alter the migration of BB5 cells into the epidermis. The epidermal invasion of BB5 cells was markedly impaired in those mice whose LCs were depleted by 95% after repetitive tape-stripping. Because production of epidermal-derived thymocyte activating factor (ETAF) by the epidermal cells was augmented after repetitive tape-stripping, the diminished migration of BB5 cells into tape-stripped epidermis did not result from a decrease in ETAF production which is thought to attract T cells chemotactically. These results suggest that Ia+ LCs may play an inductive role in the preferential migration of T cells into the epidermis.

Mycosis fungoides with oral involvement. A case report and literature review

Mycosis fungoides, also known as T-cell lymphoma, is a low-grade malignant lymphoma predominantly affecting the skin. Intraoral manifestations are infrequently seen clinically. A case of mycosis fungoides with oral involvement and a review of the literature is reported.

The value of morphometry in the ultrastructural diagnosis of Mycosis fungoides

To assess the value of morphometry in the ultrastructural diagnosis of Mycosis Fungoides (MF), skin biopsy specimens from 43 patients with established MF and 28 with non-MF lymphoid skin infiltration were studied by transmission electron microscopy. Morphometrical measurements were done on the nuclei of the infiltrating lymphoid cells. The study showed that the nuclear contour index (NCI) taken alone has a very poor diagnostic value. A more reliable way to assess morphometrically the nucleus of MF cells is to combine two parameters: the nuclear surface area and the NCI, as proposed by McNutt and his group. Although the sensitivity of this method is only 43% (McNutt et al. obtained a sensitivity of 63%, analyzing a smaller number of patients), it surprisingly has a highly significant prognostic value. Most of the patients classified as positive by this method had a very aggressive course of their disease or died from it, while most of the patients who were considered as negative had an indolent course of disease or were at a stage of remission. It is suggested that other cellular expressions may be of importance in the recognition of MF cells. It is therefore proposed that, in combination with ultrastructural immunocytochemistry, such parameters be assessed. It is hoped that the results of such a study will determine the number of parameters necessary to better recognize MF cells, thus making early diagnosis of the disease possible.

Reactivity of monoclonal antibody BE 2 in different stages of mycosis fungoides and in benign dermal infiltrates

The cutaneous infiltrate in mycosis fungoides (MF) is predominantly composed of T4-positive T-cells. Attempts to distinguish the early stages of this condition from benign inflammatory infiltrates using anti-T3, T4 and other T-cell-associated antibodies have hitherto been unsuccessful. Recently a monoclonal antibody BE 2 has been described as selectively reacting against leukemic cells in patients with cutaneous T-cell lymphoma. To investigate whether the BE 2 antigen is differentially expressed in different stages of MF and benign dermatoses, thus facilitating diagnosis, especially of early MF, the reactivity of monoclonal antibody BE 2 against cutaneous infiltrates from such conditions was assessed. In the early stages of MF only a small number of reactive cells was present. In benign inflammatory infiltrates, especially in those that clinically and histologically were hardly distinguishable from early MF, BE 2 reactivity was essentially the same as in eczematous-stage MF. Lesions from plaque and tumor stage MF contained large numbers of BE 2-reactive cells. Our results indicate that expression of BE 2 is associated with the stage of a given MF lesion and is essentially identical in early MF and eczematous lesions with a similar histopathological appearance.

Abatement of Sézary syndrome lesions following treatment with acyclovir

Sézary syndrome is a malignant form of cutaneous T cell lymphoma in which patients characteristically present with generalized pruritic erythroderma and large numbers of circulating Sézary cells in the peripheral blood. Several previous studies have proposed that viruses may play a role in the cause of cutaneous T cell lymphoma. This report describes a 68-year-old man with Sézary syndrome who received a seven-day course of intravenous acyclovir for treatment of disseminated herpes zoster and was noted to have almost complete disappearance of generalized erythroderma and pruritus. Since acyclovir has been shown to selectively inhibit viral DNA polymerase, the observed clinical response is strong evidence that viruses play a role in the cause of cutaneous T cell lymphoma. Mechanisms that could explain the observed response are discussed, and further studies on the utility of antiviral agents for treatment of cutaneous T cell lymphoma and on possible inhibitory effects of acyclovir on retroviruses are recommended.

The value of nuclear contour index in the diagnosis of mycosis fungoides. An assessment of current ultrastructural morphometric diagnostic criteria

Skin biopsy specimens from 43 patients with established mycosis fungoides (MF) and 28 with non-MF lymphoid skin infiltrations were studied by transmission electron microscopy. The nuclear contour index (NCI) of infiltrating lymphoid cells was obtained by means of a Zeiss Videoplan computer and measuring tablet. Classification of the material into MF and non-MF groups was done according to the diagnostic criteria used by McNutt et al. (1980, 1981) and Meijer et al. (1980); this study evaluates the usefulness of these previously published criteria based on quantitative electron microscopy. Statistical analysis confirmed that the mean NCI (MNCI) of the lymphoid cells of patients with MF is significantly greater than that in patients with other lymphoid infiltrates (P less than 0.001). However, all published diagnostic criteria (McNutt et al., 1980, 1981, and Meijer et al., 1980) tested in the authors' larger patient population yielded lower sensitivity than has been reported. The diagnostic criteria based on values of MNCI, percentage of lymphoid cells with NCI greater than 7, and percentage of lymphoid cells with nuclear profile area of greater than 30 microns2 reported by McNutt et al. (1981) appear to be better than others, and provide the highest sensitivity rate, which is in the range of 44% to 47%. There were no false-positive findings. It was concluded that the use of ultrastructural morphometry according to the techniques and diagnostic criteria of McNutt et al. (1981) is useful in the diagnosis of MF.

Mycosis fungoides with multiple oral mucosal lesions. A case report

Mycosis fungoides is a cutaneous T-cell lymphoma which in its later stages affects extracutaneous sites, including the oral mucosa. A case is presented in a 69-year-old male in which oral involvement was widespread and rapidly progressive. Although gingival involvement, as seen in this patient, is relatively rare, it is useful for the periodontist to be aware of the oral manifestations of this disease since cutaneous lesions would most likely be covered if the patient were to present for consultation on an ambulatory basis.

Photochemotherapy in cutaneous T cell lymphoma and parapsoriasis en plaques. Long-term follow-up in forty-three patients

Forty-three patients with clinical plaque- and tumor-stage mycosis fungoides, the erythrodermic/Sézary syndrome variant of mycosis fungoides, and parapsoriasis en plaques were treated with oral psoralens and ultraviolet A (PUVA). Pretreatment skin biopsies, evaluated by light microscopy, revealed seventeen diagnostic, seventeen suggestive, and nine nonspecific specimens. Clinical and histologic parameters were followed for an average of 38.4 months (range, 4-67 months). Twenty-five patients had complete clearing, and fourteen did not respond. Most patients in the complete-response group had either plaque lesions of mycosis fungoides or parapsoriasis en plaques prior to PUVA. Most patients in the no-response group had either tumor lesions or the erythrodermic/Sézary mycosis fungoides at the start of PUVA. In the no-response group the treatment modalities used prior to PUVA were twice the number used in the complete-response group. Patients in the complete-response group had clearing of their lesions after an average PUVA dose of 117 joules/cm2. Relapse occurred in seventeen patients after an average remission time of 6.3 months and responded to additional PUVA. Patients whose skin remained clear after the first course of PUVA continued to have clear skin for up to 58 months, with an average complete remission of 29.5 months by the end of the study period. Histologic evaluation before PUVA and at clearing revealed a definite trend toward a normal microscopic picture, but at least a mild inflammatory infiltrate usually persisted. At the end of the study period, the lesions of ten patients had entirely cleared for an average of 44 months, the lesions of five had cleared during a second course of PUVA, five had stable limited-plaque disease while receiving maintenance PUVA, eleven were undergoing electron beam radiation therapy or chemotherapy for progressive disease, ten had died, and two patients were lost to follow-up. Therefore, in the early stage of mycosis fungoides, PUVA may induce significant disease-free intervals. Prior treatment with a variety of modalities, the patient's age, and/or the duration of disease may affect response to PUVA.

Cutaneous T-cell lymphoma presenting as a rapidly enlarging ocular adnexal tumor

A 63-year-old man, in good health previously, developed swelling and erythema of the right upper eyelid which progressed to involve both eyelids and surrounding tissues. After one month, he had a 9.0 x 9.0 x 3.5 cm mass despite two attempts at incisional drainage and treatment with antibiotics. Multiple asymptomatic erythematosus nodules (2-3 cm in diameter) developed on his back, trunk, and arms four weeks after onset of the eyelid erythema and swelling. Biopsies of two upper back papules and the eyelid disclosed cutaneous T-cell lymphoma, a lymphoproliferative malignancy of thymus derived lymphocytes originating in the skin. Systemic chemotherapy resulted in a marked decrease in the ocular adnexal mass but lymphomatous meningitis and quadriplegia developed. The patient died four months later; an autopsy was not performed. This case demonstrates that cutaneous T-cell lymphoma may rarely have its initial manifestation as a rapidly enlarging eyelid tumor.

The effect of aging and chronic sun exposure on human Langerhans cell populations

ATPase histochemistry was used to examine Langerhans cell (LC) populations in the skin of young persons with no evidence of solar damage and older adults with chronic actinically damaged skin. The number of LC was significantly decreased in the older age group. Significantly fewer LC were observed in exposed vs covered skin in the older individuals; no such disparity was noted in the younger subjects. Morphologic alterations in ATPase-positive cells were noted in some specimens, most of which were taken from the exposed skin of elderly persons. The results suggest an independent, although possibly additive, quantitative and qualitative influence of aging and chronic sun exposure on the LC population. Decreased numbers of LC in the sun-damaged skin of elderly individuals may play a critical permissive role in the development of cutaneous carcinoma.

Diagnostic criteria in Sézary's syndrome: a multiparameter study of peripheral blood lymphocytes in 32 patients with erythroderma

In order to define additional diagnostic criteria for the early diagnosis of Sézary's syndrome (SS), peripheral blood lymphocytes of 32 patients with erythroderma, including 8 patients with SS, 4 patients with erythrodermic mycosis fungoides, 14 patients with an erythroderma on the basis of atopic or chronic dermatitis, and 6 patients with erythrodermic psoriasis, were investigated by computer-assisted morphometry. The degree of nuclear indentation, expressed as the nuclear contour index (NCI), was measured on electron micrographs. The mean NCI and the percentages of cerebriform mononuclear cells (CMC), defined by a NCI greater than or equal to 6.5, were calculated. In addition, the percentages of lymphocytes, T and B cells, and the distribution of T-cell sub-populations as defined by Fc-receptors (T mu, T gamma) and monoclonal antibodies (OKT3, OKT4, OKT8, HLA-DR) were determined. Statistical analysis showed as most discriminating parameters for the differentiation between SS and benign forms of erythroderma: high percentages of lymphocytes (50% or more), an expanded OKT3+, OKT4+ population with an OKT4/OKT8 ratio greater than 10, a mean NCI value greater than or equal to 5.5, the presence of more than 20% CMC, as well as the presence of cells with a NCI greater than or equal to 11.5. The total leukocyte and lymphocyte counts, as well as the percentages of B, T, T mu, and T gamma cells had limited value for the early diagnosis of SS.

Pattern of distribution and intensity of lymphoblastogenesis as an aid to distinguishing pseudolymphomas from lymphomas

Pseudolymphomas and malignant lymphomas may be distinguished on the basis of their proliferative activities, evaluated by radioautography after incorporation of tritiated thymidine. In malignant lymphomas, cells synthesizing DNA are numerous and are distributed regularly in the infiltrate. In pseudolymphomas many atypical cells do not synthesize DNA, and those labelled with [3H]TdR are often grouped in restricted areas of the infiltrate.

A second look at intraepithelial Langerhans cells in mycosis fungoides and related disorders. Ultrastructural study with special reference to Langerhans granules and virus-like particles

Skin biopsies of patients with small and large plaque parapsoriasis, premycotic lesions and mycosis fungoides in different stages were examined. Special attention was paid to the relationships between Langerhans cells (LC) and the neighbouring keratinocytes and lymphocytes. At the contact areas of LC and keratinocytes as well as LC and lymphocytes, particular cell membrane phenomena were observed. Aggregations of Langerhans granules and fusions of granules with LC plasma membranes were found exclusively at LC-keratinocyte interfaces. At LC-lymphocyte contact zones cell membrane appositions were seen. In all cases investigated, virus-like particles were mainly found in LC and indeterminate cells (IDC). In 3 cases lymphocytes also contained these particles. It was of particular interest that virus-like particles were observed in skin specimens of all diseases investigated. Discrimination of these particles from other cellular organelles - especially lysosomes - was difficult, however. The significance of our findings, particularly regarding to the supposed virus aetiology of cutaneous T cell lymphomas, is discussed.