Primary Renal Lymphoma: An Unusual Finding Following Radical Nephrectomy. Case Report
The patient underwent further investigations to confirm the diagnosis of primary renal lymphoma. Currently, the treatment for renal lymphoma is not surgical, but rather chemotherapy. We present this case because very few studies have been published, which contributes to the literature by understanding the presentation of this entity mimicking a clear cell tumor.
In adult patients, PRL is often present on only one side of the
kidney. Occasionally, patients with PRL present nonspecific symptoms and signs,
flank pain, weight loss, fever, hematuria and a palpable mass3. The lack of
precise knowledge of the disease has led to different therapeutic approaches
and the reported prognosis in general has been very poor, with 75% mortality
before one year after the diagnosis was established4.
We review this case of primary renal lymphoma that was diagnosed
based on the histopathological report of the surgical specimen after performing
radical nephrectomy as a diagnostic suspicion of renal cell carcinoma.
Case Presentation
A 48-year-old female presented with the following medical conditions
Systemic arterial hypertension in treatment. She denied any allergies or
history of surgery. She reported a history of asthenia and adynamia for three
months, accompanied by intermittent pain in the left flank. She denied having
hematuria, fever or weight loss. She underwent enhanced CT examination (Figures
1,2) at our hospital and a mass (10 x 9 cm in diameter) was noted in the
left kidney.
Figure 1: Axial computed tomography
revealing a mass at the left kidney without enhancement upon administration of
contrast medium (red dots). With measures of 9x 8 cm with 8 HU
Figure 2: Computed tomography coronal
section showing a left kidney mass located at the upper pole (red dots) with
measures of 10x 9 cm that has contact with the spleen
On physical examination, the abdomen was distended due to adipose
tissue, normal bowel sounds were auscultated and abdominal mass is palpated at
the level of the left renal fossa. There was no sign of either lymphadenopathy
or hepatosplenomegaly.
Her laboratory results were as follows: (Table 1)5.
|
Test |
Observed
Value |
Reference
Range |
|
hemoglobin
level |
9.5g/dL |
12.1-15.1
g/dL |
|
leukocyte
count |
3.4 x109 |
4.0-11.0
x 103/µL |
|
platelets |
155x 103 |
150-450
x 103/µL |
|
erythrocyte
sedimentation rate |
34,00
mm/h |
0–15
mm/h |
|
glucose |
77
mg/dL |
70-130
mg/dL |
|
sodium |
127
mmol/L |
135-145
mmol/L |
|
potassium |
4.70
mmol/L. |
3.5-5.0
mmol/L |
|
lactate
dehydrogenase |
896 U/L |
140–271
U/L |
|
serum
creatinine |
0.7
mg/dL |
0.6-1.3
mg/dL |
|
albumin |
3.40
g/dL |
3.5-5.5
g/dL |
|
alanine
transaminase (ALT) |
15 U/L |
7-56
U/L |
|
aspartate
transaminase (AST) |
34 U/L. |
5-40
U/L |
Given the suspicion of left kidney cancer radical nephrectomy and
lymph node dissection were performed. With the following surgical findings: (Figure
3) Kidney measured 7 x 6 x 5 cm, with a tumor located in the upper pole of
approximately 12 cm, with abundant newly formed vessels, loose and firm
adhesions tumor-spleen and tail of pancreas, one artery, one vein and one
ureter (Figure 3).
Figure 3: Surgical specimen
A) Surgical specimen resulting from radical nephrectomy with lymph
node indicated by the red arrow.
B) Macroscopic section from the pathology service.
An open approach was performed with a Chevrone-type incision,
transperitoneal approach. The average operating time was 2 h 30 min and the
estimated blood loss was 1500 ml due to the abundant neo formed vessels that
the tumor had.
The tumor was sent to the pathology department and histological
examination revealed the following: (Figure 4)
(A) An infiltrate of atypical lymphoid cells was observed with a
diffuse growth pattern that erased the architecture of the renal parenchyma
(10x).
(B) In another section, we can identify the same infiltrate with
respect to two glomeruli of the residual kidney (asterisk)(10x).
(C) At higher magnification, the atypical lymphoid cells are medium
to large with vesicular chromatin and evident nucleoli alternating with areas
of necrosis (arrowheads)(40x).
(D) Abundant mitotic figures are observed at the center (arrows).
Comparison of the size of the lymphoid cell defined as large (arrowhead), which
is larger than the size of the nucleus of a histiocyte (circle) (40x).
Postoperative pathology and immunohistochemistry indicated diffuse large B-cell
lymphoma localized only to the kidney6.
Figure 4: Microscopic section of the
pathology service
A) An infiltrate of atypical lymphoid cells is observed with a
diffuse growth pattern that erases the architecture of the renal parenchyma
(10x).
B) In another section we can identify the same infiltrate respecting
two glomeruli of the residual kidney (asterisk)(10x).
C) At higher magnification, the atypical lymphoid cells are medium
to large with vesicular chromatin and evident nucleoli that alternate with
areas of necrosis (arrowheads)(40x).
D) Abundant mitotic figures are observed in the center (arrows).
Postoperative immunohistochemical staining (Figure 5)
revealed Diffuse large B- cell lymphoma (DLBCL) with the following results:CD20
(+), MUM1 (+), CD10 (-), Bcl2 (+), Bcl6 (+), CD3 (-) and Ki-67 (>80% +).
Figure 5: Immunohistochemistry staining of
the resected left renal kidney
The antibodies used were as listed
in A, B, C, D, E, F, G each representative graph (×200).
A) CD20: (+) 100%
B) Mum 1 (+) 100%
C) CD10 (-)
D) BCL2 (+) 100%
E) BVL6 (+) 90%
F) CD3 (-)
G) KI-67 (+) 80%
Bone marrow biopsy and CT of the chest region did not reveal any
evidence of lymphoma invasion. Based to these findings, the patient was
diagnosed with PRL. After the operation, the patient was admitted to the
intensive care unit because of hypovolemic shock. She remained in intensive
care for 3 days; two packs of blood were transfused, with a control hemoglobin
of 9.2 g/dL. The patient remained hospitalized for 7 days and was discharged
with a referral to the hematology service to assess adjuvant chemotherapy based
on the histopathological results.
She was evaluated by the hematology department in the outpatient
clinic, who decided to prescribe the RCHOP regimen: 6 cycles of a combination
of 1 g cyclophosphamide on day 1,80mg epirubicin on day 1,3mg vindesine on day
1 and 10 mg dexamethasone on days 1-5 (1 cycle, 28 days). The patient is
currently being monitored and has been disease-free for two years.
Follow-up included CT scans of the chest, abdomen and pelvis every 6
months, as there was no established follow-up regimen for these patients.
Epidemiology
Primary renal lymphoma (PRL) is an infrequent but clinically
important entity. While the existence of true PRL (originating solely within
the kidney) remains debated, it represents a rare manifestation of lymphoma,
distinct from secondary renal involvement observed in 30-60% of
lymphoproliferative disorders6. Diffuse large B-cell lymphoma constitutes the most common
histological subtype7,10.
Epidemiologically, PRL demonstrates a male predominance
(male-to-female ratio of 1.6:1) and typically presents in older adults, with a
mean age of approximately 72 years6,11. Bilateral involvement
is uncommon, reported in only 2% of cases6. While generally
considered an aggressive malignancy with a median survival of 15 months, this
figure likely reflects diagnostic delays and historical treatment approaches6.
Pathophysiology
The pathogenesis of PRL is incompletely understood. The paucity of
lymphoid tissue within the renal parenchyma suggests that the disease
originates in the renal capsule, subsequently infiltrating the kidney8.
Alternatively, chronic inflammatory kidney conditions may predispose to PRL
development by attracting lymphoid cell infiltration, ultimately resulting in
lymphomatous transformation9. Tumor proliferation commences in the interstitium, with the
underlying nephrons and vasculature providing a scaffold for tumor growth,
thereby preserving renal contour3. As the tumor enlarges, compression of the surrounding renal
parenchyma ensues, potentially leading to architectural distortion1.
Clinical
presentation
Clinical presentations are variable, ranging from asymptomatic
discovery as an incidental renal mass (in approximately 50% of patients) to
non-specific renal symptoms (flank pain, hematuria, altered general condition)
or systemic B-cell symptoms in advanced stages11. Differential diagnosis
should include other renal tumors, particularly in the presence of atypical
renal mass characteristics or unexplained renal symptoms, warranting
consideration of PRL, particularly given its potential for rapid systemic dissemination12.
Currently defined diagnostic criteria include: (I) renal mass
presence, (II) absence of extrarenal lymphomatous involvement (viscera or lymph
nodes) and (III) exclusion of leukemic hematoma and bone marrow involvement1.
Imaging
Radiological findings on
contrast-enhanced computed tomography (CT) scans typically reveal a solitary
mass exhibiting minimal or absent enhancement. Isolated perinephric lymphoma,
while infrequent (<10% of cases), is highly suggestive of PRL. [3, 9] The
absence of calcifications, homogenous post-contrast attenuation and lack of
renal vein thrombus or mass effect are also differentiating features in
solitary renal tumors4.
Definitive diagnosis requires
pathological confirmation via needle biopsy or, frequently, post-nephrectomy
examination of the surgical specimen due to the similarity of imaging
characteristics to renal cell carcinoma13.
Treatment
Treatment strategies have evolved since PRL’s initial description in
1956, encompassing surgery combined with adjuvant radiotherapy, surgery alone
and systemic chemotherapy14. Current treatment typically involves 6-8 cycles of
cyclophosphamide, doxorubicin, vincristine and prednisone (CHOP) or, for
CD20-positive non-Hodgkin lymphoma, in combination with rituximab (R-CHOP) to
improve 5-year survival14,15.
Preoperative biopsy confirmation is crucial to avoid unnecessary
radical nephrectomy, enabling standardized routine chemotherapy with
potentially favorable prognosis15.
The patient in this report presented with an incidentally discovered
left renal mass. Initial suspicion of renal cell carcinoma prompted open
nephrectomy, with subsequent histological evaluation revealing diffuse large
B-cell PRL. The patient received six cycles of R-CHOP, with follow-up
examinations revealing no local recurrence.
Conclusions
This case highlights the importance of considering PRL in the
differential diagnosis of renal masses. While histological evaluation remains
paramount, increased awareness of characteristic clinical and radiological
features can guide appropriate management, potentially precluding unnecessary
surgical intervention. Further research is needed to optimize diagnostic and
therapeutic strategies for this rare malignancy.
Declarations
Contributors
All authors contributed to planning, literature review and conduct
of the review article. All authors have reviewed and agreed on the final
manuscript.
Competing
interests
None.
Patient consent
for publication
Informed consent was obtained from the patient, consent form
available upon request.
Ethics approval and consent to participate
Consent for treatment and open access publication was obtained or
waived by all participants in this study. Clinical Trials issued approval
NCT06525467. Consent for treatment and open access publication was obtained or
waived by all participants in this study. Mexican Institute of Social Security
issued approval 98337030. Written informed consent was obtained from the
patient for the publication of this case report and accompanying images. The
study was registered in ClinicalTrials.gov (identifier: NCT06525467).
Funding
No Funding.
References
11. Geetha N, Abdul S,
Rajan V, Jacob PM. Primary renal lymphoma-a case. E-cancer Med Sci 2014;8:466.