DISCUSSION
Based on one of the recent studies, primary vulvar DLBCL is bi-modally distributed between the age group of 25 to 43 and 62 to 79 with a mean age of 58. Our patient is a 79-year-old elderly woman. Clinically, the patient with vulvar DLBCL may present with complaints of tender to non-tender mass with or without ulceration. Erythema, edema, and pruritus may also be present.4 Our patient presented with the complaint of a hard nodule in the right labia majora, which appeared to be an ulcerative peri-urethral mass on examination.
Since there are only a few reported cases of primary vulvar DLBCL in medical literature, it might be diagnostically challenging. The differential diagnosis for vulvar DLBCL ranges from inflammatory lymphoid conditions (lichenoid dermatoses, extramedullary myeloid cell tumor, Langerhans cell granulomatosis) to carcinomas (Neuroendocrine carcinomas like Merkel cell or metastatic, lymphoepithelioma-like, poorly differentiated squamous cell, Bartholin’s gland adenocarcinoma) and other conditions like melanoma, rhabdomyosarcoma, extraosseous Ewing’s sarcoma/primitive neuroectodermal tumor, lipoma, and Bartholin gland cyst or abscess.5 Pelvic MRI emerges as the most effective imaging tool for this purpose.6,7
In cases of DLBCL, the typical IHC analysis findings involve large, abnormal lymphocytes that are negative for CD3 but positive for CD20, exhibiting a Ki-67 labeling index surpassing 80%. To determine the cell of origin, staining for CD10, Bcl-6, and MUM-1 is conducted using the Hans algorithm.8 Confirmation of the double-expression phenotype involves staining for Bcl-2 and c-myc.9Additionally, Epstein-Barr virus in situ hybridization staining assists in identifying EBV-positive DLBCL. In some instances, DLBCL may be suspected despite negative findings for CD3 and CD20 in H&E staining. In such scenarios, it’s important to entertain the likelihood of a poorly differentiated carcinoma or a small round-cell tumor as part of the standard diagnostic process. Nevertheless, the spectrum of potential diagnoses broadens to include CD20-negative DLBCL and anaplastic large-cell lymphoma (ALCL) when lymphoma is under consideration.10
In our case, immunohistochemistry analysis revealed the tumor cells were positive for CD20, BCL6, MUM1, CMYC, and BCL2 and negative for CK, CD3, CD10, SOX11, and Ki67 70%.
The primary treatment used for vulvar lymphoma is typically R-CHOP therapy, sometimes followed by radiotherapy. Recent studies have highlighted the significance of the cell type causing DLBCL, with Activated B Cell (ABC) and Germinal Centre B Cell (GCB) DLBCLs showing varying responses to standard treatment like rituximab and CHOP chemotherapy (R-CHOP). Patients with GCB-DLBCL usually respond well to R-CHOP, while those with ABC-DLBCL may not.11,12
In comparison to nodal NHL, genital lymphomas seem to be less aggressive and show a very low incidence of recurrence. The prognosis of the genital lymphomas appears to be very good with a 5-year survival rate occurring between 80 and 90%.13–15