Primary cutaneous large B cell lymphoma masquerading as lupus vulgaris

Primary cutaneous large B cell lymphoma, leg type is a rare and aggressive variant of cutaneous B cell lymphoma. It predominantly affects elderly women, with the lower limb being the most common site of presentation. The overall prognosis is poor, compared to other cutaneous B cell lymphomas. A 47-year-old man presented with a progressively enlarging nodule over the medial aspect of the left foot since 2 months. Clinical examination revealed a nodular plaque-like lesion with central ulceration that measured 7 × 7 cm, firm in consistency, and with ill-defined margins. The initial clinical diagnosis was lupus vulgaris. An incision biopsy was done, which on histopathology and immunohistochemistry revealed a rare diagnosis of primary cutaneous B cell lymphoma, leg type. The patient was started on chemotherapy; however, he succumbed to his illness about 1 year after the initial presentation. It is a rare type of cutaneous lymphoma, which may masquerade infectious disorders such as lupus vulgaris. A detailed histopathological and immunohistochemical analysis is essential for its correct diagnosis and management. Only a handful of cases of this rare condition are reported to date. This case has been reported in view of its rarity and unusual clinical presentation.

Oncolytic virotherapy-mediated anti-tumor response: a single-cell perspective

Talimogene laherparepvec (T-VEC) is a genetically modified herpes simplex 1 virus (HSV-1) approved for cancer therapy. We investigate its effect on the clinical, histological, single-cell transcriptomic, and immune repertoire level using repeated fine-needle aspirates (FNAs) of injected and noninjected lesions in primary cutaneous B cell lymphoma (pCBCL). Thirteen patients received intralesional T-VEC, 11 of which demonstrate tumor response in the injected lesions. Using single-cell sequencing of the FNAs, we identify the malignant population and separate three pCBCL subtypes. Twenty-four hours after the injection, we detect HSV-1^T-VEC transcripts in malignant and nonmalignant cells of the injected lesion but not of the noninjected lesion. Oncolytic virotherapy results in a rapid eradication of malignant cells. It also leads to interferon pathway activation and early influx of natural killer cells, monocytes, and dendritic cells. These events are followed by enrichment in cytotoxic T cells and a decrease of regulatory T cells in injected and noninjected lesions.

A case of cutaneous large B-cell lymphoma of the legs appearing as chronic venous ulceration

We report here a case of a woman with a cutaneous large B-cell lymphoma of the legs. She had a plaque lesion, superficially ulcerated and necrotized with tumorous borders situated on the posterior side of the right leg and two red or bluish-red nodular lesions. A skin biopsy from both nodular and plaque lesion showed a diffuse infiltrate of atypical large B cells CD20(+) and CD79a(+), spanning epidermis, dermis and subcutaneous tissue. A therapeutic approach containing anti-CD20 monoclonal antibody (rituximab) was suggested.