De novo CD5-positive diffuse large B cell lymphoma solely presenting as multiple subcutaneous nodules

CD5+ Primary Cutaneous Diffuse Large B-Cell Lymphoma, Leg Type, Presenting as an Asymptomatic Nodule

Primary cutaneous diffuse large B-cell lymphoma, leg type (PCDLBCL-LT), is a rare and aggressive variant of primary cutaneous lymphoma that typically expresses B cells as well as MUM1/IRF4, BCL2, and FOXP1, whereas BCL6 may be present or undetectable. We present a case of CD5+ PCDLBCL-LT presenting as a 6 mm pink-bluish nodule on the mid-left thigh, which was concerning for basal cell carcinoma. The histological examination reveals the presence of an intradermal proliferation of large, atypical CD5+, CD20+ BCL2+, BCL6+, MUM-1+, and Cyclin-D1+ lymphocytes in a nodular, diffuse interstitial and perivascular distribution. Because the patient presented with a small, single nodule, the systemic treatment of multiagent chemotherapy was avoided and localized electron beam radiation therapy with rituximab was initiated instead, achieving complete response. Early identification of PCDLBCL-LT is key for maximal therapeutic benefit and prognosis; it is important to consider PCDLBCL-LT on the differential when evaluating small, single nodules on the lower extremities of elderly patients.

Primary cutaneous methotrexate-associated B-cell lymphoproliferative disorders other than EBV-positive mucocutaneous ulcer: clinical, pathological, and immunophenotypic features

Methotrexate (MTX)-associated B-cell lymphoproliferative disorders (B-LPD) may first present in the skin. Epstein-Barr virus (EBV)-positive mucocutaneous ulcer (EBVMCU) is now a well known disease listed in the 2017 World Health Organization classification. However, primary cutaneous MTX-associated B-LPD (pcMTX B-LPD), other than EBVMCU, appear to be underestimated, and their distinctiveness remains unproven. This study aimed to document the clinicopathological characteristics of nine patients with pcMTX B-LPD that were not EBVMCU to extend our understanding of this peculiar disease. The cohort included three males and six females, with a median age of 74 years (range 54-83 years). All patients were treated with MTX for RA. Of nine patients, four presented with a solitary lesion, and five had multiple lesions. Histologically, five cases showed a polymorphic pattern, and four showed a monomorphic pattern. Immunohistochemically, four cases showed positive EBER staining, and one showed positive CD5 staining. In eight cases, once pcMTX B-LPD was diagnosed, methotrexate was immediately withdrawn. All eight of these patients experienced spontaneous regression and achieved complete remission (CR), without relapse. The patient with CD5 positivity received cytotoxic chemotherapy as the initial treatment. This patient achieved a CR after the initial treatment, but eventually experienced disease relapse resulting in death. We also revealed that pcMTX B-LPD and MTX-associated EBVMCU exhibited similar biological behaviours. We concluded that most pcMTX B-LPD cases could be cured by stopping MTX treatment. We also highlighted the fact that pcMTX B-LPD and MTX-EBVMCU had overlapping features. This finding suggested that pcMTX B-LPD and MTX-EBVMCU might share an underlying mechanism.

CD5-Positive Primary Cutaneous Diffuse Large B-Cell Lymphoma-Leg Type

Most primary cutaneous B-cell lymphomas (PCBCL) are CD5 negative, and only a few cases were found to express CD5. We report the first well-documented CD5+ primary cutaneous diffuse large B-cell lymphoma-leg type (PCDLBCL-LT). A 71-year-old woman with a history of Multiple Sclerosis was admitted because of a nodule at the left thigh. Histological examination of the skin biopsy disclosed a diffuse dermal infiltration by large lymphoid cells. Immunohistochemistry revealed that these large cells were positive for CD5, CD20, CD79a, MUM1/IRF4, Bcl6, Bcl2, and cytoplasmic IgM/λ, whereas CD3, CD56, CD23, CD21, CD10, CD30, cyclin D1, CD68, lysozyme, myeloperoxidase, and CD34 were not detected. Thus, the diagnosis of a CD5+ PCDLBCL-LT was made. Despite treatment, the patient died 11 months after initial diagnosis.

Subcutaneous diffuse large B-cell lymphoma with intraocular involvement

Here, we present an observational case report of choroidal involvement of subcutaneous diffuse large B-cell lymphoma (DLBCL). An 85-year-old female presented with a growing mass on her left abdominal wall that had been gradually growing over 2 months, which was diagnosed as subcutaneous DLBCL. A total of 1.5 months after her initial diagnosis, she presented with decreased peripheral vision of her right eye with intermittent pain for 1 month, and nausea and dizziness for 3 days. A large choroidal mass with vitreous seeding was found and vitreous aspiration with flow cytometry established the diagnosis of intraocular DLBCL. No tumorous lesions were detected anywhere else. Therefore, the patient was diagnosed as stage IV subcutaneous DLBCL with solely intraocular involvement, and was subsequently treated with systemic and intravitreal chemotherapy. A total of 9 months later, she achieved complete remission. It was concluded that subcutaneous extranodal DLBCL is a very rare form of non-Hodgkin lymphoma that can involve only the choroid.

De novoCD5-positive diffuse large B-cell lymphoma of the skin arising in chronic limb lymphedema

We report the case of a 79-year-old woman with a longstanding lymphedema of the right arm who developed a skin lymphoma involving the right wrist area. Microscopically, the lesion was composed of numerous centroblasts infiltrating both the dermis and the subcutaneous tissue. Phenotypic investigations showed expression of CD20, CD79a, and bcl-2 protein by neoplastic cells. In addition, these cells were CD5 positive. No expression of anaplastic large cell lymphoma kinase (ALK), CD10, CD23, CD30, CD43, bcl-6, cyclin D1, p53 or p16INK4a could be seen. Polymerase chain reaction (PCR) analysis demonstrated a clonal rearrangement of the genes coding for the kappa light chain of the immunoglobulin (Ig). No rearrangement of the genes coding for the Ig heavy chain, t(14;18) or t(11;14) chromosome translocations, or Epstein-Barr virus (EBV) genomic sequences could be found. The tumor was classified as stage IE and was first cured by complete surgical excision. Nineteen months later, a recurrence was noted in the right elbow area. This study further illustrates that lymphoma of the skin may complicate chronic limb lymphedema. Like most of the previously reported cases, this neoplasm belonged to the category of diffuse large B-cell lymphoma. However, it showed CD5 expression as a singular feature.

Effective in vivo purging with rituximab and autologous peripheral blood stem cell transplantation in a woman with CD5 positive primary cutaneous diffuse large B-cell lymphoma

Generalized subcutaneous tumors developed without any other sites of the disease in a Japanese woman. Skin biopsy revealed CD5(+) and CD20(+) atypical diffuse large cells infiltrating subcutaneous tissues. The diagnosis was CD5(+) primary cutaneous diffuse large B-cell lymphoma. Tumor-specific PCR showed the existence of malignant cells in the peripheral blood and bone marrow. After three cycles of chemotherapy, she was remained in partial remission. Peripheral blood stem cells (PBSC) were harvested after the fourth cycles of chemotherapy combined with rituximab for in vivo purging. The contamination of tumor cells in PBSC was negative with PCR. She then underwent autologous peripheral blood stem cell transplantation using purged PBSC and has remained in complete remission for the past 24 month.