Primary cutaneous B-cell lymphoma

Introduction to primary skin B-cell lymphoma Primary cutaneous B-cell lymphoma (PCBLC) is a type of NHL, a heterogeneous malignant disease that originates in the lymphoma system. About 25% of the NHL occurs at the end of the knot. In addition to the gastrointestinal tract, the skin is the second most common site of extranodal involvement. basic knowledge Sickness ratio: 0.05% Susceptible people: no special people Mode of infection: non-infectious Complications: proteinuria

Primary skin B-cell lymphoma etiology

(1) Causes of the disease

There are many questions about the presence of malignant B cells in the dermis and localized skin at the predilection sites in many cases, although subpopulations of epidermal T cells are known to homing or recirculating to the skin, but no skin immunosurveillance is considered. In the presence of the B cell population, IgA is present in the secretions, such as sweat, but no B cell accumulation areas such as the gastrointestinal tract lymph node group and the respiratory tract Weier's ring are found. It is inferred that the skin and lymph node drainage form a whole, resulting in Lymphocyte proliferative response to antigen stimulation directly targets the skin. Some scholars believe that there are expressions of organ-specific homing receptors expressed by various normal and malignant lymphocytes, and keratinocytes secrete cytokines such as TNF and IL-1. , they affect ligand and receptor adhesion (for delayed antigen 4 / vascular cell adhesion molecule 1 and lymphocyte function-associated antigen 1 / intercellular adhesion molecule 1), these receptors may be necessary for lymphocyte homing to the skin In theory, skin lymphocytes themselves also express skin-specific homing receptors, which cannot circulate when not bound to endothelial cells of the skin.

Dendritic cells for antigen presentation, such as dendritic cells of the dermis, may play an important role in the development of PBCL. It is inferred that various causes play a role in the progression of PCBLC, such as immunological factors, infectious factors, chromosomes. Factors and genetic factors, various infectious agents, viruses and bacteria are thought to play a role in the progression of PBCL. The relationship between Burkitt's lymphoma in Africa and Epstein-Barr virus has led observers to examine this virus in PCBLC. Epstein-Barr virus-infected transplant patients eventually developed into PCBLC. However, inconsistencies were found in patients with PCBLC, and the role of cutaneous lymphoma was still controversial. Burg et al also reported that 3 patients with PCBLC were infected with human T-cell leukemia/lymphoma virus. There were no evidence of immunodeficiency in these patients, and 3 cases were from African epidemics.

European researchers report that PCBLC is associated with pseudo-lymphoma around the skin infected with chronic atrophic extremities. Garbe et al found high titer serum antibodies in four patients with PCBLC, but no chronic Lyme disease. Clinical evidence, Cerroni and other applications of PCR analysis of 50 PCBLC wax blocks, found that only a small part (18%) of Borrelia burgdorferi DNA, the authors suggest that this spiral infection rate may be high in PCBLC patients, just because of PCR Analysis In some cases, no specific DNA was detected. It should be noted that most of the skin lymphomas were positive (3 out of 4), however, many studies in the United States showed no obvious relationship, so regional differences may result in Europe. It is positively related, but not in North America.

(two) pathogenesis

Some genetic and chromosomal abnormalities are well known in the development of nodular B-cell lymphoma. This observation was not observed for PCBLC, t(14;18)(q32;q21) is 70%~ In 90% follicular nodular lymphoma, this translocation caused bcl-2 rearrangement and overexpression, which blocked apoptosis. On the contrary, the observer found that follicular central lymphoma originating from the skin is rare. (14; 18) translocation or bcl-2 expression, therefore, suggesting that it may be helpful in distinguishing between primary and secondary cutaneous lymphoma, however studies have shown that both primary and secondary skin invasions have bcl-2 Expression, so it is still controversial in clinical practical application value.

PCBLC is currently considered to be a follicular central cell origin. However, some researchers have noted that PCBLC is very similar to MALT lymphoma in clinical progression, immunophenotype and pathogenesis. They believe that PCBLC originates from marginal cells and in fact It is proposed to apply the term skin-associated lymphoid tissue lymphoma, at least as a subpopulation of marginal zone lymphoma of PCBLC. Recently, molecular analysis of PCBLC has shown that PCBLC has intraclonal diversity due to high somatic mutations. These findings suggest an antigen-inducing process from transformed follicular central B cells.

Primary skin B-cell lymphoma prevention

Some reports that the occurrence of PCBLC is related to spirochete infection. When the skin is locally infected, antibiotic treatment can be applied to prevent the occurrence of PCBLC.

Primary skin B-cell lymphoma complications Complications

Generally no special complications.

Primary skin B-cell lymphoma symptoms Common symptoms Pimple nodules night sweat protein

PCBLC usually develops purple pimples or nodules with isolated, localized red spots, occasionally multiple or clustered defects in a limited skin, as well as peripheral erythema, smaller papules, invasive plaques and Or) erythema, a wide range or ulcers are rare, special subtypes may have a good site, such as follicular central lymphoma occurs in the scalp and trunk, immune cell tumors occur in the extremities.

Staging, once the diagnosis of PCBLC is established, a comprehensive medical history inquiry and physical examination should be performed to rule out systemic sexual assault. The symptoms of B, such as fever, night sweats and weight loss, should be asked, including lymphoma and palpation of liver and spleen. Comprehensive physical examination, staging procedures including peripheral blood cell count and classification, multi-organ chemical detection (including LDH) chest X-ray, abdominal and pelvic CT scan, gallium scan and bone marrow biopsy, when the patient is diagnosed with cutaneous plasmacytoma Evaluation of plasma or urine M protein (plasma protein electrophoresis / urinary protein electrophoresis), for patients with PCBLC, if there is less than 6 months of onset, there should be no evidence of systemic insults, it is not clear how often the staging should be repeated, no physical examination for the physical examination It is not clear whether the infringement of evidence is necessary to proceed in stages.

Examination of primary skin B-cell lymphoma

1. Histopathology: The histological features of various subtypes of PCBLC are very similar. However, the characteristics of each subtype are important for classification. The epidermis is normal in appearance. Usually, normal collagen tissue separates the normal epidermis from lymphocytes. In superficial dermal tissue, early lesions generally infiltrate the perivascular and peri-glandular areas, and old lesions tend to diffusely infiltrate, from the dermis to subcutaneous fat, with or without reactive lymphoid follicles. Diffuse or nodular infiltration is common in the bottom layer, and massive infiltration can lead to destruction of the gland structure. It can be seen that a large number of reactive T cells exist in the periphery or mixed with malignant B cells. In the old lesions, the reactive infiltration is usually very Less, although initially monomorphic, there may or may not be a mixture of various tissue cells, plasma cells and immunoblasts. Eosinophils and neutrophils may also exist, but are typically rare, and some Mitotic images are more common, and the morphological characteristics of B lymphocytes in the infiltrating site can vary from one subtype to another.

2. Immunophenotype: It is helpful for the diagnosis of PCBLC. Up to now, the most ideal specimen is fast frozen section tissue. However, flow cytometry is more reliable for light chain restriction and abnormal phenotypic detection, and some single Cloned antibodies can be well detected for wax block tissue, which is helpful for the differential diagnosis of PCBLC.

3. Immune genotype: In malignant lymphoma, the same Ig receptor is expressed from the daughter cells of mature cells to achieve a detectable amount, so clonal gene rearrangement, Ig heavy chain, and light chain cloning genes can be observed. Rearrangement supports the malignant properties of PCBLC, and some researchers believe that clonality experiments are a reliable criterion for distinguishing between reactive inflammation and malignant proliferation, and are helpful in cases with a small amount of malignant cell infiltration.

Diagnosis and diagnosis of primary skin B-cell lymphoma

Diagnostic criteria

The staging of patients with PCBLC is still inconsistent. It is not applicable to the NHL Ann Arbor staging of the primary skin. According to this staging, extranodal invasion such as skin should be classified as stage IV, suggesting that the prognosis is poor. Obviously, it is more necessary for PCBLC. Accurate staging system, the recommended staging of Burg et al in 1984 is similar to CTCL's tumor nodular metastasis system, but it is not widely used. Recently, the international NHL prognostic factors are based on multicenter research to design an international index for invasive lymphoma. The international index includes: age, activity status, stage, extranodal invasion and LDH. This international index evaluates 125 cases of systemic low-grade lymphoma and finds an important prognostic tool that can identify different remission periods and Patients with the possibility of survival.

1. Inert subtypes include: 1 bubble central lymphoma; 2 immune cell tumor / marginal zone lymphoma.

2. Moderate malignant subtype: Large B-cell lymphoma including the leg.

3. Unshaped and other subtypes: 1 plasmacytoma; 2 intravascular large cell lymphoma / malignant hemangioendothelioma; 3 sets of lymphoma; 4 rich in T cell B cell lymphoma.

The diagnosis of PCBLC is difficult. It depends not only on histological diagnosis, but also on immunophenotypic and tumor genes for diagnosis. There is no standard for the diagnosis of PCBLC. Therefore, all available diagnostic methods must be applied to obtain a clear diagnosis.

Differential diagnosis

It is mainly distinguished from reactive lymphocytosis. Because of its similar characteristics, reactive lymphocyte proliferation (RLH) refers to reactive lymphocyte proliferation caused by various antigenic stimuli. These antigens have insect bites ( and ). ), tattoos, wounds, vaccines, anti-epileptic drugs, acupuncture and injections that cause allergic reactions, due to similar clinical and histopathology, often confused with PCBLC, which may be a precursor of PCBLC, clinically, brown-red papules can be seen Plaques or nodules, which may exist in isolation or in groups, often occurring at the head, torso and lower extremities. Other parts of the invasion include the nose, scrotum and nipple, and the extremities of the extremities are usually spread by bites. Borrelia burgdorferi causes infection.

The material in this site is intended to be of general informational use and is not intended to constitute medical advice, probable diagnosis, or recommended treatments.