Introduction: Plasmacytoma is a rare plasma-cell neoplasm, which includes bone and extramedullary types. While most cases occur in the head and neck, our report presents an unusual case of extramedullary plasmacytoma (EMP) in the penis, emphasizing the diverse locations of this condition. Case Presentation: An 88-year-old man, post-hydrocelectomy, presented with a palpable penile mass causing urinary symptoms. CT scans revealed a tumor with extracapsular spread and potential urethral involvement. Biopsy confirmed lymphoma, later identified as extramedullary plasmacytoma. A follow-up whole-body CT scan was performed, revealing multiple areas of bone rarefaction of the dens of the axis. His diagnosis has been further specified as multiple myeloma. Treatment with lenalidomide, bortezomib, and dexamethasone led to significant penile tumor reduction and improved voiding symptoms after three cycles. Conclusion: A rare case of primary EMP in the penis is reported, with only two documented cases of EMP in this location. The etiology of EMP remains unclear, possibly linked to chronic infection, irritation, or inflammation. EMP typically occurs in soft tissues, commonly in the head and neck, presenting as submucosal masses with symptoms in individuals aged 50–70. Diagnosis requires demonstrating monoclonal plasma cell infiltration and excluding multiple myeloma. While EMPs are often treated with radiotherapy, a patient with bone rarefaction suggestive of multiple myeloma requires first-line chemotherapy. This case highlights the importance of recognizing myeloma-defining events for appropriate treatment.

1.
Wang
Y
,
Li
HY
,
Liang
TT
,
Han
YP
,
Wang
XJ
,
Wei
X
et al
.
Primary extramedullary plasmacytoma of the penis: a case report
.
Jpn J Clin Oncol
.
2013
;
43
(
10
):
1030
3
.
2.
Weber
DM
.
Solitary bone and extramedullary plasmacytoma
.
Hematol Am Soc Hematol Educ Program
.
2005
;
2005
(
1
):
373
6
.
3.
Scarberry
K
,
Jegalian
A
,
Valent
J
,
Wood
HM
.
Solitary extramedullary plasmacytoma of the penis
.
Urol Ann
.
2014
;
6
(
3
):
242
3
.
4.
Zhu
X
,
Wang
L
,
Zhu
Y
,
Diao
W
,
Li
W
,
Gao
Z
et al
.
Extramedullary plasmacytoma: long-term clinical outcomes in a single-center in China and literature review
.
Ear Nose Throat J
.
2021
;
100
(
4
):
227
32
.
5.
Rajkumar
SV
.
Multiple myeloma: every year a new standard
.
Hematol Oncol
.
2019
37
Suppl 1
62
5
.
6.
Medical Masterclass Contributors
Firth
J
.
Haematology: multiple myeloma
.
Clin Med
.
2019
;
19
(
1
):
58
60
.
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