Description
A 21-year-old man diagnosed as having a case of stage IV diffuse large B-cell lymphoma with CD20 positivity on immunohistochemistry underwent a baseline contrast-enhanced CT (CECT) scan for staging. The CECT scan revealed extensive lymphomatous deposits in the orbit, paranasal sinuses, thyroid, pleura, lungs, liver, pancreas and bilateral kidneys, and in the cervical, mediastinal and retroperitoneal nodes. In addition, the left seminal vesicle was enlarged and hypodense (figure 1). The right seminal vesicle was normal. The urinary bladder and prostate were also normal. Further, an 18F-fluorodeoxyglucose positron emission tomography scan was performed, which also revealed uptake in the region of the left seminal vesicle with a standardised uptake value value of 19.3 (figure 2).
Figure 1.
Axial contrast-enhanced CT (CECT) showing an enlarged and hypodense left seminal vesicle (arrow).
Figure 2.
Maximum intensity projection images of positron emission tomography CT scan showing multifocal increased 18F-fluorodeoxyglucose (FDG) uptake in the thyroid (star), mediastinum (curved arrow), retroperitoneum (arrowhead), kidneys (outlined arrow) and left seminal vesicle (thin arrow).
Tumours of the seminal vesicles can be primary or secondary. Primary tumours can be benign (adenomas, cystadenomas) or malignant (adenocarcinoma, cystosarco phyllodes, sarcomas, neuroendocrine tumours, lymphomas). Secondary tumours are those that spread from the prostate, rectum and bladder, or lymphomas.1
These lesions cannot be differentiated on imaging and the differential diagnosis is ultimately made by histological analysis.2
Lymphomas frequently involve extranodal structures in the abdomen, including the solid organs (liver, spleen, kidneys and pancreas) as well as the hollow viscus (the gastrointestinal tract). However, in the pelvis, the incidence rate of lymphomas in locations other than the lymph nodes, such as the urinary bladder, prostate, seminal vesicles ovary, uterus, cervix and vagina, is known to be very low.
Extranodal involvement is more common in non-Hodgkin’s lymphoma and is seen in 20–40% of these cases. The gastrointestinal tract is involved in 10–30% of cases and the head and neck in 20%.3
Learning points.
Lymphomas can, rarely, involve pelvic organs such as the urinary bladder, prostate, seminal vesicles ovary, uterus, cervix and vagina.
Malignancies occurring in the seminal vesicle are both primary and secondary, however, they have no characteristic imaging appearance.
Footnotes
Competing interests: None declared.
Patient consent: Obtained.
Provenance and peer review: Not commissioned; externally peer reviewed.
References
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