Penile Mass Reveals Systemic Diffuse Large B-Cell Lymphoma
A rare case report describes a painful penile mass as the initial sign of systemic diffuse large B-cell lymphoma, highlighting diagnostic challenges in extranodal malignancies.
Diffuse large B-cell lymphoma (DLBCL) involving the penis is an exceptionally rare extranodal malignancy that often presents with nonspecific clinical features. Because of this atypical presentation, it is frequently misdiagnosed as penile carcinoma or infectious conditions before definitive diagnosis is achieved.
In this case report, a 58-year-old man presented with a progressively enlarging painful penile mass that persisted for three months. The lesion was refractory to empirical antibiotic therapy, prompting further investigation through ultrasound-guided core biopsy of the penile shaft mass.
The biopsy revealed diffuse large B-cell lymphoma, centroblastic type, non–germinal center B-cell subtype with MYC and BCL-2 double expression. Fluorodeoxyglucose positron emission tomography/computed tomography (FDG PET/CT) demonstrated intense uptake in the penis with additional gastric involvement confirmed by biopsy, consistent with Lugano stage IV disease.
The patient received curative-intent systemic chemo-immunotherapy with Rituximab plus Cyclophosphamide, Doxorubicin, Vincristine, and Prednisone (R-CHOP) and subsequently achieved complete metabolic remission on follow-up FDG PET/CT. This case highlights an unusual presentation of systemic DLBCL as a painful penile mass.
This report underscores the pivotal role of FDG PET/CT in detecting occult extranodal involvement, accurately staging disease, and guiding appropriate management. Clinicians should maintain a high index of suspicion for lymphoma when evaluating penile masses that do not respond to standard antimicrobial therapy.