Lymphoma of the kidney. A report of 11 cases

Acute kidney failure reveals primary renal non-Hodgkin lymphoma

A male patient in his 60s was admitted to our hospital with symptoms of dyspnoea, asthenia, diaphoresis and acute kidney failure. No tumour or infection was detected in initial screening. However, laboratory examination suggested that the acute kidney failure was due to an intrarenal cause, exhibiting a tubular injury pattern and indications of tumour lysis syndrome. Initial hydration therapy, paired with intravenous rasburicase, rapidly improved the kidney function. Unfortunately, the kidney function deteriorated once again, prompting a kidney biopsy that revealed an aggressive diffuse large B-cell non-Hodgkin lymphoma of the kidney. The chemotherapy, comprised of R-CHOP scheme, led to a full recovery of the kidney function and complete remission of the lymphoma. Primary renal non-Hodgkin lymphoma without nodal manifestation is rare, and its pathophysiology is poorly understood. Therapy schemes can vary significantly between cases, relying primarily on non-renal-specific haemato-oncological guidelines. Therefore, further studies are needed to develop the best therapeutic approaches.

B‑cell lymphoblastic lymphoma‑associated renal damage: A case report and literature review

Lymphoblastic lymphoma (LBL) is a highly malignant form of lymphoma with rapid progression and high mortality. According to the World Health Organization immunophenotype, it is classified into T-lymphoblastic lymphoma (T-LBL) and B-lymphoblastic lymphoma (B-LBL). B-LBL often involves lymph nodes and extranodal locations, such as the skin, bones, and soft tissues. However, renal damage as an initial symptom is very rare in B-LBL. The present study presented a rare case of renal involvement in a 30-year-old male patient with B-LBL presenting with acute renal failure with bilateral renal enlargement. Renal involvement is rare in B-LBL, and nephrologists should improve the understanding of this disease.

The Differential Diagnosis of Medullary-Based Renal Masses

CONTEXT.—

Renal malignancies can be divided into cortical- and medullary-based tumors, the latter of which classically infiltrate the renal parenchyma by extending between nonneoplastic structures. Although high-grade cortical tumors can rarely exhibit the same growth pattern, the infiltrative morphology should elicit a differential diagnosis to be considered in each case. However, these diagnoses can be challenging to distinguish, especially on small renal biopsy samples.

OBJECTIVE.—

To provide an overview of the clinical, gross, and microscopic findings; genetic and molecular alterations; and immunohistochemical evaluation of medullary-based renal tumors and other tumor types with overlapping morphologies and growth patterns.

DATA SOURCES.—

Literature review and personal observations were used to compile the information in this review.

CONCLUSIONS.—

Collecting duct carcinoma is a prototypical medullary-based tumor, and although diagnostic criteria exist, it remains a diagnosis of exclusion, especially with ancillary techniques aiding the recognition of established as well as more recently described neoplasms. Other medullary-based malignancies included in the differential diagnosis include renal medullary carcinoma/renal cell carcinoma unclassified with medullary phenotype, fumarate hydratase-deficient renal cell carcinoma, and upper tract urothelial carcinoma. Moreover, other rare entities should be excluded, including metastatic carcinoma, lymphoma, and melanoma. In addition to potential prognostic differences, accurate diagnoses can have important surgical and clinical management implications.

Bilateral primary renal diffuse large B-cell lymphoma: a rare presentation of paediatric renal disease mimicking juvenile nephronophthisis

A 12-year-old boy presented with a prolonged history of headache, fatigue and hypertension. Initial investigations were consistent with presumed non-oliguric end-stage renal disease, leading to a provisional diagnosis of juvenile nephronophthisis. Subsequent imaging demonstrated bilaterally enlarged kidneys without cystic change. Mutation analysis was negative for nephronophthisis, causing diagnostic uncertainty which prompted renal biopsy. Histology revealed a primary renal diffuse large B-cell lymphoma which was highly responsive to chemotherapy, including the anti-CD20 monoclonal agent, rituximab. Renal function improved during lymphoma treatment, with residual chronic kidney disease stage 3a once chemotherapy was completed. Atypical diagnostic features should always prompt re-evaluation of a patient. In this case, the delayed malignancy diagnosis did not have an adverse effect on patient survival or morbidity. The outcome for primary renal lymphoma (PRL) has improved markedly following the introduction of rituximab.

Burkitt Lymphoma Presenting With Intracardiac Mass and Tumor Thrombosis in the Anterior Mediastinum With Literature Review

Burkitt lymphoma manifesting as an intracardiac mass is a rare entity. This report describes the case of a 10-year-old boy who presented with an intracardiac mass and tumor thrombosis in the anterior mediastinum that proved to be Burkitt lymphoma. The LMB-96 chemotherapy protocol was given and at the end of the treatment there was still residual mass. A biopsy was performed and the pathology revealed thymus tissue. The patient has been in complete remission for 3 months. Burkitt lymphoma has a short doubling time and an intracardiac lesion can become life threatening. Early recognition and prompt treatment are crucial in achieving optimal outcomes.

Abdominal pain in a 5-year-old girl with bilateral nephromegaly: Answers

Renal involvement in non-Hodgkin lymphoma is a recognized development, but it mostly follows a diagnosis of lymphoma. We describe a rare case of a T-cell-type non-Hodgkin lymphoma that first presents as nephromegaly in a 5-year-old girl admitted to the emergency department with abdominal pain. Further investigation revealed bilateral nephromegaly, but the results of blood tests, imaging studies, and bone marrow aspiration were inconclusive. During the second week of hospitalization, significant physical examination revealed an enlarged lymph node in the anterior cervical chains, confirming a diagnosis of Non-Hodgkin's lymphoma. This case illustrates that it is important to have a high degree of suspicion in any patient presenting with unexplained enlarged kidneys without any identifiable cause because it could be the first presentation of a hematologic malignancy.

Primary Renal Lymphoma Identified in a Robot-Assisted Laparoscopic Nephroureterectomy Specimen

Background: Although renal involvement is often present in non-Hodgkin's lymphoma (NHL), primary renal NHL is a rare diagnosis.

Case Presentation: We present a case report of a 72-year-old asymptomatic male who underwent a robot-assisted laparoscopic radical nephroureterectomy on an atrophic left kidney with evidence of an infiltrating mass. Pathology report demonstrated a grade 1 follicular lymphoma.

Conclusion: Lymphoma is a differential that should be considered when evaluating a renal mass. Chemotherapy and radiation are the mainstays of treatment.

Disseminated Renal Burkitt Lymphoma With Malignant Inferior Vena Caval Thrombosis in a Child

The most common causes of renal mass with malignant venous thrombosis are Wilms' tumor and renal cell carcinoma. Although renal involvement may occur in disseminated lymphomas, primary renal Burkitt lymphoma (BL) is rare. Vascular tropism is not a usual feature of lymphoma; thus, primary renal BL with venous extension is distinctly unusual. However, it is important to diagnose this entity because such patients respond well to medical management and may not require surgery. We report a pediatric case of primary renal BL with malignant vascular thrombus and systemic dissemination where biopsy was diagnostic and enabled appropriate treatment.

Ewing sarcoma/primitive neuroectodermal tumor of the kidney: clinicopathologic analysis of 34 cases

The present study describes the clinicopathologic analysis of 34 cases of Ewing sarcoma/primitive neuroectodermal tumor occurring in the kidney. The patients were 21 males and 13 females with an age range of 6 to 44 years. Clinically, patients presented with multiple symptoms including hematuria, pain, and/or lump in the abdomen. Nephrectomy was performed in most of the cases. Grossly, whole of the renal parenchyma was involved by a variegated tumor. Histologically, the tumor was composed of monomorphic, small, and round cells arranged in a variety of patterns. Rosettes, geographical areas of necrosis, and arborizing vascular pattern were the prominent histologic features. The nucleus was monomorphic and round. Anisonucleosis was also noted in some cases. The nucleus was mostly hyperchromatic. A mixture of hyperchromatic and powdery chromatin was noted in few cases. Immunohistochemically, MIC2 (CD99) was positive in 32 of 34 cases followed by neuron-specific enolase (9/12 cases), vimentin (8/14 cases), synaptophysin (1/8 cases), and S-100 protein (1/4 cases). Molecular analysis by reverse transcriptase-polymerase chain reaction that was carried out in 26 cases revealed presence of EWS-FLI-1 type 1 translocation in 12 cases, EWS-FLI-1 type 2 translocation in 10 cases, and both type 1 and type 2 EWS-FLI-1 translocation in 2 cases. Two cases did not demonstrate any translocation. Follow-up data were available for 17 of 34 cases. Local recurrence of the tumor was seen in 4 patients, and 10 patients were recorded to have distant metastasis in various organs, such as lung, bone, and lymph node, during the course of the disease.

Prevalence and patterns of renal involvement in imaging of malignant lymphoproliferative diseases

BACKGROUND

Renal involvement in patients with lymphoproliferative disease is an uncommon radiological finding.

PURPOSE

To determine its prevalence and radiological appearances in a patient population.

MATERIAL AND METHODS

All forms of lymphoproliferative disease (ICD: C81-C96) were considered. From January 2005 to January 2010, 668 consecutive patients with lymphoproliferative disease were identified with the help of the radiological database and patient records. Inclusion criteria were complete staging including appropriate CT scan and/or MRI. All stored images (initial staging and follow-up examinations) were reviewed.

RESULTS

Review of all stored images revealed renal infiltration in patients with non-Hodgkin lymphoma (11 of 364 = 3.0%; median age = 65 years, m:f = 6:5) but also multiple myeloma (2 of 162 = 1.2%; median age = 72 years; m:f = 1:1) and leukemia (5 of 101 = 4.9%; median age = 12 years; m:f = 2:3). There were no cases of renal infiltration in 41 patients with Hodgkin's disease. In total there were six patients with solitary lesions, five patients with diffuse renal enlargement, four patients with perirenal lesions, and two patients with direct invasion of the kidney.

CONCLUSION

In leukemia the most common imaging pattern is diffuse enlargement. In the other subtypes of lymphoproliferative disease no specific correlation between typical CT patterns and subtype of lymphoproliferative disease can be found. The prevalence of renal involvement is in line with earlier studies. Contrary to earlier reports, multiple lesions were not found to be a common pattern.

Pediatric renal non-hodgkin lymphoma with inferior vena cava thrombosis

Involvement of kidneys in disseminated lymphoma is common. Primary lymphoma of the kidney is rare and has varied imaging characteristics. Abdominal lymphadenopathy can result in encasement and narrowing of the retroperitoneal vessels occasionally causing thrombosis. We present a 12-year-old boy with renal lymphoma and inferior vena caval thrombus; discuss the rarity of this presentation as well as other differential diagnosis and the need for confirmation of histopathologic diagnosis before instituting therapy in pediatric renal tumors.

Lymphoid neoplasms of the urinary tract and male genital organs: a clinicopathological study of 40 cases

Lymphoid neoplasms of the urinary tract and male genital organs are relatively rare, comprising less than 5% of all primary extranodal lymphomas; only a handful of small case series and isolated case reports have been published describing their predominant sites and subtypes. We identified 40 patients with lymphoid neoplasms of the urinary tract and male genital organs. Hematoxylin and eosin slides and immunohistochemical stains were reviewed, and follow-up data were also obtained. Twenty-six of 40 cases (65%) were primary genitourinary lymphomas. Mean age at diagnosis was 56 years (range 4-86 years). Among renal, bladder, and ureter lymphomas, a male predominance was noted (1.6:1). The subtypes of the lymphoid neoplasms observed were diffuse large B-cell lymphoma (17 cases, 43%); Burkitt lymphoma, extranodal marginal zone lymphoma, SLL/CLL, and follicular lymphoma (4 cases, or 10% each); B-cell ALL (2 cases, 5%); B-cell lymphoma, unclassifiable, with features intermediate between diffuse large B-cell lymphoma and Burkitt lymphoma, mantle cell lymphoma, plasmacytoma, polymorphic post-transplant lymphoproliferative disorder, and peripheral T-cell lymphoma NOS (1 case, or 2.5% each). In most cases, the genitourinary tract was the site of initial presentation. Genitourinary tract lymphomas most commonly occurred in the kidney. B-cell non-Hodgkin's lymphomas predominated, with diffuse large B-cell lymphoma being the most common subtype in the entire group. Extranodal marginal zone lymphoma was seen only in the kidney, rather than the bladder, where it is typically thought to be more common. Although this study confirms the predominance of diffuse large B-cell lymphoma in extranodal sites, the findings also highlight the variety of lymphomas that may occur in the genitourinary tract. This diversity of subtypes affirms the importance of fully characterizing lymphomas by immunohistochemistry and other modalities, which are indispensable for accurate diagnosis.

Isolated renal relapse of a case with non-Hodgkin's lymphoma

A 29-year-old woman with left pleural effusion and a mass in anterior mediastinum was admitted. Transthoracic needle aspiration from the mass revealed findings consistent with nodular sclerosis variety of Hodgkin's disease. The patient was in remission after six cycles of ABVD followed by mediastinal radiotherapy. Ten months later CT scan showed three hypodense masses in the right kidney. Ultrasound guided renal biopsy revealed diffuse large B cell lymphoma. Retrospective re-evaluation of the archival specimens of the mediastinal mass was also consistent with diffuse large B cell lymphoma. After induction chemotherapy (four cycles of DHAP) she underwent high dose chemotherapy (BEAM) and autologous peripheral blood stem cell transplantation. She is still in remission for 7 years after transplantation. In conclusion, renal involvement during advanced lymphoma is quite common but isolated renal relapse in NHL is a rare situation. Although renal infiltration generally shows a poor prognosis, long-term survival may be achieved with high dose chemotherapy and autologous peripheral blood stem cell transplantation.

Bilateral primary renal lymphoma with orbital metastasis in a child

Primary renal lymphoma (PRL) is a rare condition and bilateral PRL even rarer. Most of these bilateral PRL have been reported in adults. We describe a 3-year-old male with bilateral primary renal B cell lymphoma with orbital metastases. We discuss the difficulties in diagnosis and management of this rare presentation of lymphoma.

Primary renal lymphoma presenting with hypertension

Primary renal lymphoma (PRL) is a rare lymphoma which usually presents with hematuria, flank pain, abdominal mass, and weight loss. PRL is more diagnosed in adults than children. We describe an asymptomatic child who presented with hypertension and was subsequently diagnosed with primary renal lymphoma. This case represents an atypical presentation for PRL.

Marginal zone lymphoma of both spleen and kidney displaying transformation into large B-cell lymphoma

We report a case of simultaneous involvement of the spleen and the left kidney in a marginal zone lymphoma with a monotypic lymphoplasmacytic cell component, which transformed into a diffuse large B-cell lymphoma of the immunoblastic type. PCR showed that the small and large B-cell populations carried the same type of immunoglobulin heavy chain gene rearrangement. This type of rearrangement was detected in the spleen, the latero-aortic lymphadenopathy and the kidney demonstrating that it is the same lymphoma that affected both organs and the lymph nodes. Primary renal lymphoma is very rare and only a few cases of renal marginal zone lymphoma, MALT type, have been reported. Involvement of simultaneous multiple sites has been described in MALT type lymphoma, but splenic involvement secondary to renal MALT lymphoma seems to have never been observed. Nevertheless, in our case the huge size of the spleen associated with splenic hilar node involvement is consistent with primary splenic marginal zone lymphoma. The extension into latero-aortic lymph nodes of this lymphoma can explain secondary kidney involvement. The nodal Kaposi's sarcoma observed in this patient of Mediterranean origin was probably coincidental.

Sonography in Benign and Malignant Renal Masses

Ultrasonography and CT have allowed improved detection of renal mass lesions. Though ultrasonography is less sensitive in the characterization of the renal mass lesions, it is often the first imaging modality for evacuation of the kidneys. This article gives an overview of the benign and malignant renal mass lesions and the role of ultrasonography in their characterization.

Long-term survival after combination chemotherapy for bilateral renal malignant lymphoma in a dog

CASE HISTORY

A 6-year-old, entire male Flat-coated Retriever was presented with a history of lethargy, polydipsia and seizures. Clinical chemistry had shown marked azotaemia.

CLINICAL FINDINGS AND DIAGNOSIS

Radiography and ultrasonography revealed bilateral renomegaly, and cytology of fine needle aspirates from the kidneys was diagnostic of malignant lymphoma. The dog was treated with a modified high-dose cyclophosphamide-, vincristine-, and prednisolone-based chemotherapy protocol, achieved remission, and returned to normal quality of life. Survival time was 346 days from the time of diagnosis.

CLINICAL RELEVANCE

Malignant lymphoma in the kidneys of dogs has been considered to carry a uniformly poor prognosis. Long-term remission after medical treatment has not previously been reported. The favourable outcome in this case illustrates the limitations of clinical staging in determining the outcome for individual patients.

Renal Involvement of Non-Hodgkin’s Lymphoma and Its Prognostic Effect in Childhood

OBJECTIVE

To evaluate renal involvement in childhood lymphoma and define its prognostic effects.

PATIENTS AND METHODS

One hundred and four patients with non-Hodgkin's lymphoma and renal involvement on admission to a single center between 1972 and 2003 were evaluated retrospectively. Blood urea nitrogen, serum creatinine, uric acid, electrolytes, and lactate dehydrogenase levels, as well as urinalysis, were evaluated. One or more of the following imaging methods were performed: intravenous urogram, ultrasound, computed tomography, and magnetic resonance imaging. The chi2 test was used to compare the groups. The Kaplan-Meier survival method was used to calculate survival rates, and the log-rank test was used to compare groups with respect to survival. Survival rates were also compared in two different time periods (before 1991 and after 1991).

RESULTS

There were 76 boys and 28 girls with a median age of 6 (0.9-16) years. The renal infiltration pattern was nodular in 62 patients (59.6%) and diffuse in 40 patients (38.5%). Two patients had tumoral masses that originated from their kidneys (1.9%). Renal involvement was bilateral in 75 patients (72.1%); the remaining 29 patients had unilateral involvement. The overall survival rate was 42.5% with a median follow-up of 64 months. The factors that had a statistically significant impact on survival were high creatinine (p = 0.00001) and blood urea nitrogen levels (p = 0.0001), the onset of tumor lysis syndrome (p = 0.01), and the need for dialysis (p = 0.009). The survival rate was higher in the time period after 1991 (p = 0.01).

CONCLUSION

Impaired renal function is a poor prognostic factor for non-Hodgkin's lymphoma. Renal function should therefore be monitored closely. Renal dysfunction caused by direct tumoral involvement may complicate therapy and shorten survival.

Neoplasms of the Renal Medulla: Radiologic-Pathologic Correlation

Tumors of the renal medulla cover a wide spectrum, with characteristic histomorphology and variable biologic profiles. Renal medullary tumors can be categorized into benign and malignant neoplasms based on histologic features and clinico-biologic behavior. They can be further classified into pediatric and adult tumors based on the patient age group. When small, renal medullary tumors may be differentiated from the more common renal adenocarcinomas by their central location and certain demographic characteristics. Although most large malignant medullary tumors demonstrate imaging findings that are indistinguishable from those of other renal malignancies, some tumors demonstrate imaging findings that may suggest a specific diagnosis.

An unusual cause of acute renal failure: renal lymphoma

Renal involvement is a common finding in non-Hodgkin's lymphoma (NHL). Acute renal failure at initial presentation due to lymphomatous infiltration of the kidneys has been described infrequently. We report a 17-year-old male who presented with acute renal failure due to massive lymphomatous infiltration of the kidneys, which necessitated hemodialysis. The diagnosis of B-cell NHL was established by tru-cut biopsy of the kidneys and the patient had an excellent response to high-dose chemotherapy with no major complication. The presence of extrarenal involvement in the testes and the retroperitoneal lymph nodes made the diagnosis of primary renal lymphoma debatable. However, considering the delay in diagnosis and the high proliferative rate of B-cell NHL, we might postulate that the disease had originated primarily in the kidneys. We recommend that in NHL cases with severe renal involvement, full-dose chemotherapy should be instituted with meticulous clinical and laboratory follow-up in order to improve clinical and renal failure status rapidly and to avoid further dissemination of NHL.

Lymphomas diagnosed by percutaneous kidney biopsy

BACKGROUND

Occult renal lymphoma clinically mimicking renal medical disease constitutes a diagnostic challenge to nephrologists, radiologists, and renal pathologists. The clinical and radiological findings, mostly nonspecific or inconclusive, seldom obviate the need for a kidney biopsy.

METHODS AND RESULTS

We report 5 new cases of diffuse bilateral renal lymphoma diagnosed by percutaneous kidney biopsy, all presenting with acute renal failure (ARF) of unknown cause. Three cases showed an interstitial and 2 an intraglomerular/intravascular type of lymphomatous infiltration. All tumors were of B-cell lineage. Our cases add to 50 similar cases reported since 1980. Considering all 55 cases together, 39 (87%) of the 44 cases with interstitial and 5 of 11 (45%) of those with intraglomerular lymphoma presented with ARF. In contrast, 5 of 10 cases with intraglomerular but none with interstitial infiltration presented with nephrotic range proteinuria. All but 2 cases (95%) with ARF and interstitial lymphoma but none with ARF and intraglomerular lymphoma showed bilaterally enlarged kidneys. Signs of extrarenal lymphomatous involvement were detected in 24 cases (44%) at the time of kidney biopsy or shortly thereafter. However, in only 10 cases (18%), all with interstitial lymphoma, was a tumor suspected prior to biopsy, mainly based on radiographical evidence of enlarged kidneys.

CONCLUSION

Both types of diffuse bilateral renal lymphoma may clinically mimic renal medical disease. ARF in interstitial and in intraglomerular lymphoma may be due to increased intrarenal pressure and intraglomerular obstruction, respectively. Percutaneous kidney biopsy provides the most expedient means of establishing the diagnosis. Differential diagnosis includes interstitial nephritis and proliferative glomerulonephritis.

[Primary renal lymphoma]

OBJECTIVE

To describe a case of primary renal lymphoma.

MATERIAL AND METHODS

We presents a patient with a right renal mass which histological analysis revealed a non-Hodgkin Lymphoma.

RESULTS

A 78-year-old male patient with right flank pain mass was referred to our Service. He was diagnosed of renal mass by imaging studies. Inmunohistochemical investigations revealed a B-cell-type lymphoma. He received combination chemotherapy with CHOP.

CONCLUSIONS

Primary renal lymphoma is a rare disease whose existence has been questioned, because the kidney does not normally contain lymphoid tissue. Its clinical presentation is like any other renal tumor and its definitive diagnosis is by histology. Elective treatment is chemotherapy (CHOP).

Primary anaplastic large cell lymphoma of the kidney

Primary renal lymphoma is a rare disease. There is still no agreement on its development primarily in this non-lymphoid organ. Some of the reported cases are questionable because of the incomplete staging of extrarenal disease. In the present study, we describe a rare case of a 73-year-old white man presenting with right flank pain. Physical examination did not reveal any peripheral lymphadenopathy or hepatosplenomegaly. An abdominal computerized tomography (CT) showed a large tumor in the right kidney with no enlarged liver, spleen or lymph nodes. On morphological and immunohistochemical examination, the tumor fulfilled the criteria of anaplastic large cell lymphoma (ALCL). A review of the literature revealed that this is the first reported case of primary ALCL of the kidney.

Primary renal lymphoma and hypercalcemia in a child

Renal lymphoma is most frequently due to secondary lymphomatous infiltration of the kidneys in advanced stage disease. Rarely, are the kidneys the tissue of origin. We describe a 15-year-old male presenting with hypercalcemia and acute renal failure, due to a bilateral "primary B-cell lymphoma of the kidneys". The diagnosis was established by percutaneous needle biopsy of the right kidney. His disease was metastatic to multiple bones. His presenting features radiological findings and biopsy results are unique. We report his case, and review the pediatric literature.

Kidney involvement and renal manifestations in non-Hodgkin's lymphoma and lymphocytic leukemia: a retrospective study in 700 patients

Renal involvement as part of systemic lymphoma (LY) is quite frequent, however, primary extranodal renal non-Hodgkin's lymphoma (NHL) is extremely rare, and only about 65 cases have been reported in the world literature. In a retrospective study of renal manifestations in 700 patients with documented LY and chronic lymphocytic leukemia (CLL) seen at our hospital during 1986-95, 83 patients had signs of acute renal failure. Only five of these had proven renal infiltration, but none of them satisfied the criteria for primary renal LY. Glomerulonephritis (GN) has also rarely been reported in association with LY and CLL, and only 37 glomerular lesions in NHL and 42 in CLL have been documented, respectively. GN may precede, coexist, or follow the diagnosis of LY by several years. Of the 42 cases of CLL reported worldwide, 36 had nephrotic syndrome. Renal failure was seen in about one third. The most common glomerular lesion reported is membranoproliferative GN, followed by membranous GN. In our study, we found only five biopsy-proven cases with GN amongst the 700 patients seen. In this report we also briefly describe some rare interesting associated renal syndromes in CLL and NHL.

Primary malignant neuroepithelial tumors of the kidney: a clinicopathologic analysis of 146 adult and pediatric cases from the National Wilms' Tumor Study Group Pathology Center

Primary malignant neuroepithelial tumors of the kidney (NETKs) comprise a group of primitive, highly malignant neoplasms that histologically and clinically are not well characterized. A large cohort of 146 of these tumors, occurring in adults and children, has been collected at a single depository site, the National Wilms' Tumor Study Group (NWTSG) Pathology Center. The authors undertook a systematic retrospective review of the histologic, ultrastructural, and clinical features of these tumors, based on materials collected by the NWTSG and the consultation files of one of the authors (J.B.B.). Histologic features were generally those of primitive neural tumors with varying amounts of rosettes and neuropil; however, a large proportion of cases displayed unusual features such as spindle cells, ganglion cells, clear cell sarcoma-like foci, rhabdoid cells, epithelioid cells, and organoid foci. CD99 staining had been performed on 69 cases and showed membranous staining in 65. The NETKs were present in patients with a wide age spectrum, ranging from 1 month to 72 years (median, 18 years). EWS/FLI1 fusion analysis using reverse transcriptase-polymerase chain reaction and immunohistochemical stains for cytokeratin, chromogranin, and epithelial membrane antigen were performed successfully on a subset of 45 cases with available paraffin blocks. Only 13 of the 45 were fusion-positive, and there was no correlation between fusion status and histology, presence of rosettes, ultrastructural features, or cytokeratin positivity. CD99-negative cases were usually fusion-negative (six of seven cases), and all three chromogranin-positive cases were fusion-negative. Tumor staging, performed on 72 clearly defined and quantifiable cases by using NWTSG criteria, indicated that these are aggressive tumors, because only six were Stage 1, compared with 16 Stage 2, 31 Stage 3, and 19 Stage 4 lesions. The authors conclude that NETKs are a somewhat diverse group of generally aggressive, high-grade lesions that may present in a wide age range and are difficult to characterize without immunohistochemistry and cytogenetics/molecular biology.

Renal lymphoma. The diagnostic and therapeutic roles of fine-needle aspiration

This study focused on 19 patients with renal lymphoma (RL) from whom 20 initial (1 patient with fine-needle aspiration [FNA] specimens of masses in both kidneys) and 1 repeated FNA specimen were obtained. Of the 19 patients, 10 had secondary RL, 8 primary RL, and 1 transplant RL. The FNA samples were studied by smears (all cases), tissues (11), phenotyping by immunostaining (13) or flow cytometry (4), and gene rearrangement (3). The final diagnoses included 1 T-cell lymphoma and 18 B-cell lymphomas. Of the 20 original specimens, 14 were reported as positive for lymphoma, 3 suggestive of lymphoma, 1 positive for transitional cell carcinoma, and 2 unsatisfactory. The follow-up specimen showed reactive changes. Tissue correlation, available in 11 cases, confirmed a positive cytodiagnosis (7), provided a final diagnosis in the cytologically inconclusive cases (3), or revised the misdiagnosis of transitional cell carcinoma from smears (1). The phenotyping elucidated the B vs T lineage of the lymphoma in all tested cases, confirmed the positive cytodiagnosis in 10 cases, confirmed the reactive cytodiagnosis in 1 case, and helped achieve a conclusive diagnosis in 2 cases suggestive of lymphoma. Gene rearrangement studies showed light chain restriction in the 2 tested cases. FNA has an essential role in treatment planning for RL. Although FNA usually is diagnostically conclusive, a high index of suspicion and awareness of atypical or misleading cytomorphologic features are important for a correct interpretation, especially for primary RL. Ancillary testing is essential for the diagnosis in problematic cases and lays the foundation for the differential diagnosis.

Renal lymphoma: CT patterns with emphasis on helical CT

Renal lymphoma is most often seen in conjunction with multisystemic, disseminated lymphoma or as tumor recurrence. Renal lymphoma may also be seen in immunocompromised patients or, rarely, as primary disease. Computed tomography (CT) is the most sensitive, efficient, and comprehensive examination for evaluation of the kidneys in patients with suspected renal lymphoma. Helical CT in particular improves detection and characterization of lymphomatous renal involvement by optimizing contrast dynamics and data acquisition and is the current modality of choice for accurate staging of lymphoma. Typical CT patterns in renal lymphoma include single and multiple masses, invasion from contiguous retroperitoneal disease, perirenal disease, and diffuse renal infiltration. Atypical CT patterns may also be encountered and provide a diagnostic challenge. These include spontaneous hemorrhage, necrosis, heterogeneous attenuation, cystic transformation, and calcification. Solid renal masses including renal cell carcinoma and metastases are the most commonly encountered entities that mimic renal lymphoma at CT and require biopsy for definitive diagnosis. CT (particularly helical CT) is useful in the evaluation of patients with suspected renal lymphoma, and familiarity with the spectrum of findings in renal lymphoma is important for accurate diagnosis.

Primary T-cell-rich B-cell lymphoma in the kidney presenting with acute renal failure and a second malignancy

Infiltration of the kidney is commonly found in lymphoma, but acute renal failure arising from bilateral renal infiltration is uncommon. Primary renal lymphoma may occur and is usually of B-cell lineage. It is rare for patients with lymphoma to develop acute renal failure as their initial clinical presentation. Recently, an association between primary renal lymphoma and a second primary malignancy has been reported. We describe the first case of a renal T-cell-rich B-cell lymphoma presenting as acute renal failure, which was associated with a second primary pulmonary malignancy.

Primitive neuroectodermal tumor of the kidney--another enigma: a pathologic, immunohistochemical, and molecular diagnostic study

Primitive neuroectodermal tumor (PNET), the second most common type of sarcoma in the first two decades of life, rarely presents as an organ-based neoplasm. Rather, it is seen typically in the soft tissues of the chest wall and paraspinal region. We report a case of primary PNET of the kidney in a 17-year-old girl who presented with abdominal pain, hematuria, and an abdominal mass. Nodules and sheets of monotonous-appearing primitive round cells and the formation of rosettes focally were the principal microscopic features. The tumor cells were uniformly immunoreactive for vimentin, cytokeratin, neuron-specific enolase, and 013 (CD99). In addition, the characteristic translocation of PNET and Ewing sarcoma, t(11;22)(q24;q12), was detected by polymerase chain reaction (PCR). Eight previous examples of renal PNET have been reported in the literature in the past 2 years, but only three of these cases have had complete immunohistochemical evaluation with the demonstration of 013 positivity. To our knowledge the present case is the only one to date demonstrating the recurrent translocation t(11;22)(q24;q12) by PCR. Assuming that the previous cases in the literature are bona fide examples of PNET, the kidney may be another site of predilection for this usual soft-tissue neoplasm. We are once again confronted with the dilemma about the nature of the progenitor cell.

Malignant lymphoma of the kidney

BACKGROUND

Primary renal lymphoma (PRL) is a rare disease, making information including etiologic factors for PRL extremely limited.

METHODS

Clinical and pathologic findings of PRL in Japan are presented and compared with those from Western countries. The presence of Epstein-Barr virus (EBV) genomes in the tumor was also evaluated. Eight cases of PRL were collected from a review of the "Annual of the Pathological Autopsy Cases in Japan (1976-1992)". These cases fulfilled the following criteria: (1) presence of renal mass without extrarenal lymphomatous involvement at admission and (2) absence of a leukemic blood picture. For histologic and immunohistochemical studies, 10% formalin-fixed and paraffin-embedded histologic specimens were used. Presence of Epstein-Barr virus (EBV) genome was examined by polymerase chain reaction (PCR) and in situ hybridization (ISH).

RESULTS

There were five males and three females; age at admission ranged from 15 to 79 years (median 57 yr). Abdominal and/or flank pain were the most common presenting symptoms. No particular past history was present in any of the patients. Histologically, tumor cells in all cases showed a diffuse pattern of proliferation: large cell type in six cases, mixed cell type and small lymphocytic type in 1 each. Immunohistochemistry revealed B-cell nature of lymphoma cells in all cases. Neither PCR nor ISH showed the presence of EBV genome in any cases.

CONCLUSIONS

PRL is non-Hodgkin's lymphoma of predominantly large cell type with a B-cell immunophenotype. EBV etiology is unlikely in PRL.