Case report: a case of primary cutaneous diffuse large B-cell lymphoma, leg type with TdT positive in an elderly woman.

Current Understanding of Lymphoproliferative Disorders.

Primary cutaneous lymphomas (PCLs), comprising cutaneous T-cell lymphomas (CTCLs) and cutaneous B-cell lymphomas (CBCLs), are rare non-Hodgkin lymphomas with distinct epidemiological characteristics. How the incidence rates (IRs) of PCLs have changed over the past decade has not been well documented. To assess changes in IRs in overall and subtype-specific PCLs in the USA by sex, age and ethnic group. This study analysed 13 126 cases of PCL diagnosed between 2010 and 2021 using data from the Surveillance, Epidemiology and End Results programme. Age-adjusted IRs (aaIRs), 5-year relative survival and annual percentage change were calculated. The overall aaIR of PCLs was 11.9 per 1 000 000 person-years, with 8.8 for CTCLs and 3.1 for CBCLs. Among CTCL subtypes, mycosis fungoides had the highest aaIR of 5.2, whereas within CBCLs, primary cutaneous marginal zone lymphoma exhibited the highest aaIR of 1.4. Between 2014 and 2021, the aaIR of CBCLs declined annually by 4.9%. In males, aaIRs for CTCLs and CBCLs decreased by 3.5% and 4.8%, respectively, per year over the same period. Five-year relative survival was 89.3% for CTCLs and 91.5% for CBCLs. The incidence of PCLs has exhibited distinct patterns of decline among different population groups over the past decade. The continued disparities in both incidence and survival underscore the need for targeted research and interventions to mitigate demographic inequalities.

Early Surgical Excision Achieving Remission in Cutaneous B-cell LymphomaPrimary cutaneous diffuse large B-cell lymphoma, leg-type (PCDLBCL-LT), is an uncommon and aggressive form of non-Hodgkin lymphoma with a poor prognosis.We report the case of an 89-year-old woman who presented with a rapidly enlarging cutaneous nodule on her right thigh.The lesion, which appeared 1.5 months earlier, measured 22 cm and displayed homogeneous pink, structureless areas with hemorrhagic foci on dermatoscopy.The patient's history included Alzheimer's disease, epilepsy, a congenital solitary kidney, cerebrovascular disease resulting in a bedridden state, and a prior basal cell carcinoma.An excisional biopsy with a 0.5 cm margin was performed for diagnostic and therapeutic purposes.Histopathological analysis revealed diffuse infiltration by large atypical lymphocytes with hyperchromatic nuclei and frequent mitotic figures.Immunohistochemistry showed positivity for cutaneous diffuse-20 (CD20) and B-cell lymphoma-2 (BCL-2), while CD3, CD10, BCL-6, and cellular myelocytomatosis were negative.The Ki-67 proliferation index was notably high (90-95%), confirming the aggressive nature of the lymphoma.Based on these findings, a diagnosis of PCDLBCL-LT was established.Given the patient's advanced age, comorbidities, and the family's preference to avoid systemic therapy, no additional treatments such as chemotherapy or radiotherapy were pursued.The patient remained recurrence-free over a one-year follow-up period.This case underscores the importance of early recognition of atypical skin lesions in elderly patients and highlights that surgical excision alone may be an effective, minimally invasive treatment option in selected frail individuals.Early intervention not only aids in local disease control but may also help maintain quality of life without the risks associated with aggressive therapies.

Radiotherapy for indolent primary cutaneous B-cell lymphoma: an international multicenter ILROG analysis.

Primary cutaneous diffuse large B-cell lymphoma-leg type (PCDLBCL-LT) is a rare and aggressive lymphoma of elderly patients, typically affecting the lower extremities and characterized by centroblast- and immunoblast-like cells with a non-germinal center phenotype (MUM1+, BCL2+, IgM+, CD10-). CD5-positive cases are exceptionally uncommon and pose a diagnostic challenge, as CD5 expression broadens the differential diagnosis to include other B-cell lymphomas such as mantle cell lymphoma and transformed chronic lymphocytic leukemia. We describe a 70-year-old female patient who presented with a 2-cm cutaneous nodule on the lower extremity. Histopathology revealed a pandermal diffuse infiltrate of atypical large B-cells. Immunohistochemistry showed a CD5+, CD20+, MUM1+, BCL2+, IgM+, cyclin D1-profile, supporting CD5 + PCDLBCL-LT. Fluorescence in situ hybridization for MYC , BCL2 , and BCL6 rearrangements were negative, effectively ruling out double-hit/triple-hit lymphoma. The patient achieved a complete metabolic response after six cycles of R-CHOP chemotherapy, which was maintained for 24 months. However, she subsequently developed extracutaneous relapse involving the soft tissues of the extremities, trunk, and periorbital region, consistent with a progression. Treatment with a rituximab-bevacizumab combination regimen induced a second complete remission, sustained for six months at the time of reporting. Our case highlights the importance of routine CD5 testing in PCDLBCL-LT to identify this distinct subgroup and to guide appropriate differential diagnosis and patient monitoring.

Accurate identification of non-melanoma skin cancer (NMSC) using ICD-10 claims-based algorithms is largely uncharacterized. This study aimed to develop and validate claim-based algorithms for NMSC. Adult patients with psoriasis were identified in Optum Market Clarity between Oct 2015 and Dec 2020. Eligible patients had at least 1 year of claim enrollment prior to cohort entry, linked claims-EHRs, overlapping follow-up periods, and no prior malignancy. Data were randomly split into the development and validation datasets. Broad NMSC encompassed narrow NMSC (basal cell carcinoma, squamous cell carcinoma, sebaceous cell carcinoma, and malignant neoplasms of the sweat glands), Merkel cell carcinoma, carcinoma insitu, Kaposi sarcoma of skin, and cutaneous T-cell or B-cell lymphoma. The five developed claims-based algorithms consisted of 1+ diagnosis code (1) at any position; (2) at the primary position; (3) by a dermatologist; (4) at any position plus treatment procedure code; (5) at primary position plus treatment procedure code. NMSC cases and non-cases were adjudicated using EHR records. Algorithms performance measures were estimated. Of 25 647 patients (mean age 51.4 ± 15.2 years, female 53.6%), 321 broad and 281 narrow NMSC patients were identified in the development dataset (n = 12 824). Algorithm sensitivity was 89.9% (algorithm1) and 81.9% (algorithm2) but under 65% for algorithms 3-5 for broad NMSC. PPV ranged from 98.2% to 99.1%. Results were consistent in the validation dataset. This study developed and validated high-performing ICD10-based algorithms for NMSC to facilitate future dermatology research using health data.

Primary cutaneous B-cell lymphoma encompass clinically heterogeneous entities. While primary cutaneous diffuse large B-cell lymphoma, leg type (pcDLBCL-LT) is aggressive, primary cutaneous follicle centre lymphoma (pcFCL) and primary cutaneous marginal zone lymphoma (pcMZL) typically follow an indolent course. To clarify their pathophysiological basis, we perform single-cell RNA sequencing on pcFCL, pcMZL, and pcDLBCL-LT, alongside reactive B-cell rich lymphoid proliferations (rB-LP), gastric mucosa-associated lymphoid tissue (MALT) lymphoma, and systemic counterparts. Here we show that the indolent pcMZL, pcFCL, and rB-LP exhibit a persistent germinal centre reaction, not observed in pcDLBCL-LT or gastric MALT lymphoma. Further, pcMZL top expanded clones develop within lesions from naïve and not post-germinal centre B cells as currently presumed. Our data thus indicate that pcMZL and pcFCL, similar to rB-LP may be driven by (a yet unknown) antigen. While our data indicates that pcFCL exhibits some features of true lymphomas, it clearly supports the classification of pcMZL as a lymphoproliferative disease.

Low-Dose Radiotherapy for Primary Cutaneous Indolent B-Cell Lymphomas: a Multicenter Retrospective Study.

Background Cutaneous and systemic plasmacytosis is a rare disorder predominantly observed in individuals of Asian descent. The aetiology, treatment modalities, and prognosis of this condition remain unclear. Objective To describe the clinicohistopathologic features and outcomes in patients with cutaneous and systemic plasmacytosis. Methods We analysed data from 21 patients treated at West China Hospital of Sichuan university from 2011 to 2022. Results All patients exhibited characteristic reddish-brown patches or plaques, primarily located on the trunk, head, face, and neck, with one patient also showing affected soles. Lymphadenopathy was present in 38.9% (7/18), and bone marrow involvement in 100% (7/7). Polyclonal immunoglobulinemia appeared in 91.67% (11/12), with elevated IgG4 in 87.5% (7/8) and IL-6 in 83.3% (5/6). Monoclonal gene rearrangements were observed in 54.5% (6/11) of patients. Over 5.3 years, 11.1% (2/18) partially remitted, while 44.4% (8/18) progressed, with four developing multicentric Castleman disease. Limitations This is a retrospective evaluation with a small number of cases; further prospective studies are warranted to support our inferences. Conclusions Cutaneous and systemic plasmacytosis often follows a chronic, progressive course. Our findings indicate an overlap in pathological features with cutaneous marginal zone B-cell lymphoma (MZBCL) and an association with IgG4-related disease. Additionally, some cases developed into multicentric Castleman disease. Currently, no effective treatment regimen has been established for this condition.

Background: Primary cutaneous marginal zone B-cell lymphoma (PCMZL) is a rare subtype of extranodal marginal zone lymphoma that typically remains confined to the skin. While generally indolent with a favorable prognosis, its diagnosis can be challenging due to overlap with other cutaneous lymphoid proliferations. Case Presentation: A 74-year-old man presented with longstanding subcutaneous nodules (>2 cm) on both cheeks, the submental region, and the right jaw, without overlying epidermal changes. Biopsies demonstrated a low-grade B-cell lymphoma with IgM expression and plasmacytic differentiation, and next-generation sequencing identified a MYD88 p.L265P mutation. Imaging revealed mediastinal lymphadenopathy, metabolically active nodes, and splenomegaly. Given the indolent course of PCMZL, observation was initially recommended. However, due to cosmetic concerns, rituximab therapy was initiated with a planned course of eight weekly infusions. Discussion: PCMZL comprises approximately 25-30% of primary cutaneous B-cell lymphomas. It presents with erythematous or violaceous papules, plaques, or nodules, most often on the trunk and extremities. Accurate diagnosis requires integration of clinical, histopathologic, and molecular findings. Although prognosis is excellent, relapse occurs in up to 50% of patients. Management strategies vary and may include observation, surgical excision, radiotherapy, or systemic therapies such as rituximab. In this case, therapy was driven by patient preference, underscoring the importance of individualized care even in indolent disease. Conclusion: PCMZL should be considered in the differential diagnosis of persistent subcutaneous nodules. This case emphasizes both the rarity of the disease and the role of patient-centered factors in guiding treatment.

Primary cutaneous B-cell lymphoma most commonly presents as solitary or multiple violaceous papules, nodules, or plaques depending on the specific subtype. It tends to have an aggressive clinical course. Secondary cutaneous involvement of systemic or nodal lymphoma also needs to be excluded. We describe a unique case of a 73-year-old man with presentation as striking annular and arcuate lesions clinically and histologically mimicking an interstitial granulomatous dermatitis, such as granuloma annulare. Close scrutiny of the interstitial infiltrate on histology and adjunctive immunostaining established the diagnosis as diffuse large B-cell lymphoma (DLBL). This is the first description of B-cell lymphoma mimicking interstitial granuloma annulare clinically and histologically. Cutaneous T-cell lymphoma, in particular the "interstitial" variant of mycosis fungoides, is reported to closely mimic interstitial granuloma annulare. Although the skin histology suggested high grade features,due to the unusual indolent clinical presentation, the patient was monitored clinically.Five years after initial presentation, the patient developed a large fungating skin tumor on the chest wall also confirmed as DLBL. Six cycles of R-CHOP chemotherapy led to complete resolution of the chest lesion and rash. Eighteen months after completion of chemotherapy, he presented to hospital with left-sided weakness. A CT scan revealed a right temporal lobe mass, radiologically most likely lymphoma. The patient declined further treatment and died shortly afterward. This case highlights the importance of long-term follow-up of patients with DLBL, even with a seemingly indolent initial clinical presentation.

Primary cutaneous lymphomas (PCL) are extranodal non-Hodgkin lymphomas affecting the skin without other systemic involvement at the time of diagnosis. Our case was a 62-year-old patient with PCBLC who had deep and multiple skin involvement but no systemic symptoms or involvement. At diagnosis, there was widespread skin involvement of the anterior chest wall, more pronounced on the left side. The patient received RT at 30 Gy/17 fractions for the lesions located on the anterior chest wall and 20 Gy/11 fractions as a boost to the primary mass. Six months after treatment, the patient demonstrated a near-complete response. In this case report, a case of primary B-cell cutaneous lymphoma with widespread chest wall involvement, which achieved a complete response to RT, is discussed with the literature.

Primary cutaneous lymphomas (PCL) are primarily composed of cutaneous T-cell lymphomas (CTCL), followed by cutaneous B-cell lymphomas (CBCL). This study aimed to assess the incidence and survival rates of PCL in Germany. We analyzed data from the North Rhine-Westphalia Cancer Registry (2008-2021), which covers a population of 18 million. Age-standardized incidence rates and relative survival were calculated. The analysis included 3,853 patients with newly diagnosed PCL. Of these, 69.5% were CTCL, and 24.9% were CBCL. The age-standardized incidence of PCL was 10.8 per million person-years. The incidence of both CTCL and CBCL increased over time. PCL cases were also identified in children. The overall five-year relative survival for PCL was 89% (95% CI: 87-92%), with CTCL patients having a survival rate of 91% (95% CI: 88-94%) and CBCL patients of 86% (95% CI: 81-91%). Among patients with Sézary syndrome, the five-year relative survival was 53% (95%: CI:29-77%). This study represents the largest population-based analysis of PCL in Germany, including both adults and children. The incidence of PCL was higher than previously reported. Additionally, we present the first survival data for PCL in Germany, revealing a notably higher survival probability for patients with Sézary syndrome.

Cutaneous lymphomas are a heterogeneous group of extranodal non-Hodgkin lymphomas with distinct clinical and biological features, broadly classified into cutaneous T-cell lymphomas (CTCL) and cutaneous B-cell lymphomas (CBCL). With improved survival due to early detection and therapeutic advances, the emergence of second primary malignancies (SPMs) has become a clinical concern. SPMs, defined as new, distinct malignant neoplasms arising synchronously or metachronously with the index cancer, can significantly impair prognosis and quality of life. In this narrative review, we meticulously examine the current literature, to synthesize evidence on SPMs' incidence and risk factors in patients with primary cutaneous lymphomas. Evidence from population-based and institutional studies consistently demonstrates elevated risks of hematologic and solid tumors in CTCL. By contrast, data on CBCL remain limited, though recent population-based analyses suggest increased risks of certain hematologic malignancies and solid tumors. We further propose development mechanisms for SPMs, including treatment-related mutagenesis, shared genetic susceptibilities, chronic antigenic stimulation, and immune dysregulation. Lastly, we highlight the clinical implications of these findings, underscoring the need for vigilant surveillance, patient education, and tailored screening strategies. Future research should prioritize large-scale, prospective, and molecularly integrated studies to refine risk stratification and guide personalized survivorship care of this vulnerable population.

Cutaneous diffuse large B-cell lymphoma induces a macrophage immunosuppressive phenotype through IL-10 secretion∗

Surgical treatment of facial single primary cutaneous marginal zone B-cell lymphoma: A case report

The diagnostics of B-cell cutaneous lymphomas is difficult because of its clinical manifestations’ nonspecificity. Since 2015 dermoscopy has been used as an additional method for diagnostics of B-cell cutaneous lymphomas. Dermoscopy is an inexpensive, non-invasive, painless diagnostic method that allows to quickly get additional information about the disease. Currently known dermatoscopic signs in conjunction with anamnestic and clinical data may indicate a diagnosis of B-cell cutaneous lymphoma. Capabilities of dermatoscopy in the diagnosis of B-cell cutaneous lymphomas are demonstrated in this article. However, dermatoscopy cannot replace histological and immunohistochemical examinations of skin which are the “gold standard” necessary for diagnosis of B-cell cutaneous lymphoma. The molecular genetic research using PCR-method is necessary in some cases of primary cutaneous marginal zone lymphoma with rich T-cells microenvironment.

Cutaneous diffuse large B-cell lymphoma induce a macrophage immunosuppressive phenotype through IL-10 secretion

Implementation of a patient-reported outcome assessment during radiotherapy for mycosis fungoides and other cutaneous lymphomas