Pathologic characteristics of primary cutaneous T-cell lymphoma in Korea

Skeletal muscle dissemination in a dog with T-cell lymphoma

A 5-year-old spayed female American Staffordshire was referred for weakness, reluctance to move and distension of the abdomen. Three weeks before, the dog underwent surgery for excision of a nodular mass suspected to be a non-epitheliotropic cutaneous T-cell lymphoma (NE-CTCL). Computed tomography revealed heterogeneous enhancing mesenteric masses and nodular lesions of soft tissue density, and infiltration of the abdominal muscular wall. Moreover, a pattern of diffuse muscle nodules in the skeletal muscles was visible, with lesions showing homogenous, heterogeneous or ring enhancement. Necrosis was histologically observed and these lesions were infiltrated by CD3-positive and CD20-, CD79a- and Iba1-negative neoplastic lymphocytes. On the basis of the immunopathological features metastatic NE-CTCL was suspected. Skeletal muscle metastasis has been rarely reported in small animals and this case report further confirms that this possibility should be considered in dogs with lymphoma.

Evaluation of the Association Between Epstein-Barr Virus and Mycosis Fungoides

INTRODUCTION

Mycosis fungoides (MF) is the most common cutaneous T-cell lymphomas. Despite extensive studies, etiopathogenesis of MF is unknown. Environmental, infectious and genetic factors have been proposed as potential risk factors of MF. Herpes virus family members, especially Epstein-Barr virus (EBV), have been among the viral factors of interest in recent years. The aim of this study was to investigate the possible association of EBV infection with MF.

MATERIALS AND METHODS

This case-control study was performed on skin biopsy samples of 57 MF patients referred to Pathology Department of Mashhad Emam Reza Hospital from 2000 to 2011 and also on 57 melanocytic nevus samples matched with patients for age and sex. The presence of EBV in samples was evaluated by polymerase chain reaction. Statistical analysis of the data was conducted with the Statistical Package for the Social Sciences version 11.5 (SPSS Inc., Chicago, IL, USA).

RESULTS

In this study, out of 57 MF samples, there were 34 male and 23 female patients, with male:female ratio of 1.04. Mean patient age was 51.4 years. There were 22 and 4 positive cases of EBV in the case and control groups, respectively. Chi-square statistical test showed that EBV was significantly higher in case group than control (P = 0.000). There was no correlation between the presence of EBV in samples with lesion type, age and gender of the patients.

CONCLUSION

According to our study results, EBV is a likely etiologic agent or potential promoter in the pathogenesis of MF.

Pharmacokinetic analysis of rhein in Rheum undulatum L

This research aims to identify the main active compounds of Rhei undulati Rhizoma (roots of Rheum undulatum LINNE) and determine the types of anthraquinones absorbed into the body and their pharmacokinetic parameters. The boiling-water extract of the herb was administered to 12 healthy volunteers (9 men/3 women) at a dosage of 100 mg/kg the anthraquinone levels in plasma were determined with TLC, HPLC, and LC-MS. Rhein was the only anthraquinone compound absorbed by the body as determined for plasma analysis of the volunteers. The elimination rate constant of rhein in Rhei undulati Rhizoma was 0.23+/-0.02/h and the half life was 3.38+/-0.35 h. This experiment confirmed that rhein is the most important active compound absorbed by the body among anthraquinones contained in Rhei undulati Rhizoma, indicating that rhein is a promising marker substance to evaluate Rhei Rhizoma and Rhei undulati Rhizoma.

Infrequent Fas mutations but no Bax or p53 mutations in early mycosis fungoides: a possible mechanism for the accumulation of malignant T lymphocytes in the skin

Mycosis fungoides (MF) is the most frequent manifestation of cutaneous T cell lymphoma but its cause and pathophysiology remain unclear. Because progression of lesions is characteristically slow, we hypothesized that mycosis fungoides originates from an accumulation of lymphocytes due to defective apoptosis of skin homing T lymphocytes. In this study, we investigate possible alterations of three molecules regulating apoptosis, i.e., Fas antigen, Bax, and p53, at the genomic level in skin lesions from 44 patients with MF, as Fas mediates one of two major pathways for apoptosis of activated T cells. Fas mutations were found in six patients using a polymerase chain reaction and single-strand conformational polymorphism method followed by cloning and sequencing of abnormal polymerase chain reaction products. The mutations predict for defective transmission of the death signal in three cases. Immunohistochemistry demonstrated the lack of Fas protein expression on dermal lymphocytes in one case with Fas gene mutation predicting for a truncated death domain, whereas Fas protein was expressed by dermal lymphocytes in the other investigated cases. By contrast, no mutations of Bax or p53 were found, whereas immunohistochemistry demonstrated increased p53 expression in the nucleus of basal keratinocytes above the neoplastic infiltrate in some MF cases. These results support the hypothesis that Fas defects may play a role in the pathogenesis of MF.

Clinicopathological features of CD56+ nasal-type T/natural killer cell lymphomas with lobular panniculitis

Nasal-type T/natural killer cell lymphoma (TNKCL) shows frequent extranodal involvement including the skin, and is associated with a poor prognosis. We have studied six patients with nasal-type TNKCL presenting with inflammatory subcutaneous nodular lesions with a subcutaneous lymphoid infiltrate. Clinical information was obtained from the medical records of the patients and at follow-up. All cases showed features of angiocentric lymphoma on histology, although there was diffuse cellular infiltration rather than an angiocentric pattern in the subcutis. All six patients were similar in immunophenotype: positive for CD56 and either cytoplasmic CD3 or CD45RO, but negative for B-cell markers and CD30. In situ hybridization using an anti-sense Epstein-Barr virus early regions probe showed a positive reaction in all cases. All patients either died with progressive disease or showed no response to combined chemotherapy. The diagnosis of nasal-type TNKCL, which has a fatal outcome, is facilitated by detection of CD56-positive tumour cells. In evaluating lobular panniculitis including apparently benign inflammatory subcutaneous nodules, nasal-type TNKCL should be considered in the differential diagnosis, especially in Asian countries.