Pseudotumors due to IgG4 immune-complex tubulointerstitial nephritis associated with autoimmune pancreatocentric disease

Autoimmune pancreatitis (AIP) is a mass-forming chronic fibroinflammatory condition centered on the pancreatobiliary system and characterized by predominant immunoglobulin G4 (IgG4)-positive plasma cells. Recent reports have brought to light the multiorgan involvement of this disease. We describe a series of 5 cases of tubulointerstitial nephritis (TIN) associated with AIP and characterize the clinical, pathologic, ultrastructural, and immunopathologic features of TIN. The specimens consisted of 4 biopsies and 1 nephrectomy. The average patient age was 64 years (range 45 to 78) and the male to female ratio was 4:1. All had histologic and/or clinical and radiographic evidence of AIP, mass-forming sclerosing cholangitis, or both. The clinical impression in 4 patients was a renal mass or vasculitis. Two patients had renal insufficiency. Histologic preparations revealed a dense tubulointerstitial lymphoplasmacytic infiltrate. Eosinophils were often numerous. Tubulitis and tubular injury were present, along with tubular atrophy with focally thickened tubular basement membranes (TBMs). The histologic appearance ranged from a cellular, inflammatory pattern without tubular atrophy to a striking expansive interstitial fibrosis with tubular destruction. The nephrectomy specimen demonstrated a masslike nodular pattern of inflammation with normal renal tissue elsewhere. Glomeruli were uninvolved. By immunohistochemistry or immunofluorescence, numerous plasma cells in the infiltrate were positive for IgG4. TBM granular IgG deposits, predominantly of the IgG4 subclass, were detected in 4 of 5 cases by either immunofluorescence or immunohistochemistry. By electron microscopy, corresponding amorphous electron-dense deposits were present in the TBM in these cases. This type of TIN, typically characterized by a masslike lesion consisting of a lymphoplasmacytic infiltrate with eosinophils and prominent IgG4-positive plasma cells and immune-complex deposits in the TBM, may be part of a systemic IgG4-related disease, which we term "IgG4-associated immune complex Multiorgan Autoimmune Disease" (IMAD).     

Clinical significance and pathological features of ectopic lymphoid-like structures in IgG4-related tubulointerstitial nephritis

Objective To investigate the clinical significance and pathological features of lymphocytes and plasma cells infiltration and related ectopic lymphoid-like structures in IgG4-related tubulointerstitial nephritis (IgG4-TIN). Methods Complete data was collected from 24 patients with IgG4-TIN confirmed by pathology in the Peking University First Hospital. The renal specimens were examined by routine light microscopy, immunofluorescence and electron microscopy examination. In addition, immunohistochemistry was used to detect the distribution of CD20+ B lymphocytes, CD3+ T lymphocytes and CD138+ plasma cells. Results A total of 24 patients were enrolled in the study, including 21 males (87.5%), 3 females (12.5%). The age was (58.0±10.8) years (38-75 years). Pathology analysis showed ectopic lymphoid-like structures were located in 16 (66.7%) cases and Russell bodies were detected in infiltrative plasma cells of 19(79.2%) cases with IgG4-TIN. Compared with cases without Russell body formation, cases with Russell body formation in renal interstitial plasma cells were more prone to show ectopic germinal center-like structure formation (P=0.001), tubular basement membrane (TBM) electron dense deposits (P=0.040) and reduced blood C3 levels (P=0.028). Conclusions Abnormal tubulointerstitial infiltration of ectopic lymphoid-like structures and plasma cells with prominent Russell body exist in IgG4-TIN patients, which suggests the persistent activation of lymphocytes and plasma cells in renal interstitium may contribute to the pathogenesis of IgG4-TIN.     

IgG4-related tubulointerstitial nephritis

Tubulointerstitial nephritis (TIN) is a disease pattern with heterogeneous causes. Recently a specific subtype of autoimmune TIN, IgG4-related TIN, has been identified that is part of systemic IgG4-related disease/ autoimmune pancreatitis. On biopsy, this TIN shows an IgG4+ plasma cell-rich infiltrate, akin to the pancreatic tissue findings in autoimmune pancreatitis, and may show tubulointerstitial immune complex deposits. Notably, some cases may be mass-forming. Recognition of this specific type of TIN can guide appropriate patient therapy.     

Renal involvement in IgG4-related disease

IgG4-RD may affect several organs including kidneys. The kidney is involved in approximately 20% of patient with IgG4-RD. The most common intrinsic kidney disease is tubulointerstitial nephritis (IgG4-TIN). Retroperitoneal fibrosis (IgG4-RPF) may induce obstructive acute renal failure. More rarely, IgG4-RKD can manifest as a glomerular disease, in particular as a membranous nephropathy (MN). It mostly affects middle-aged to elderly men and causes acute or chronic renal dysfunction, multiple hypodense lesions on CT-Scan and various extra-renal lesions. Increased serum IgG4 and hypocomplementemia are the most important serological findings for the diagnosis of IgG4-RD and thus should be systematically assessed when IgG4-RKD is suspected. Specific diagnosis criteria for IgG4-TIN including interstitial infiltration of IgG4-positive plasma cells, storiform fibrosis and tubular basement membrane immune complex deposits have been proposed. Corticosteroids are effective and remain the first-line therapy but relapses or severe forms could respond to immunosuppressive therapy.     

Clinicopathological findings of immunoglobulin G4-related kidney disease

Immunoglobulin (Ig) G4-related kidney disease characterizing tubulointerstitial nephritis (TIN) is an organ complication recognized in IgG4-related systemic diseases that has some unique aspects compared to other types of TIN. TIN lesions in the kidney can be tumor-like, focal or diffuse. Abnormal urinalysis is usually mild or absent even in the cases with deteriorated renal dysfunction. Some cases are accidentally diagnosed from radiological findings without renal dysfunction and/or abnormal urinalysis. The typical pathological findings of TIN are unique fibrosis and infiltration of massive lymphocytes and IgG4-positive plasma cells. Glomerular lesions are rare but the complication of mesangial proliferative glomerulonephritis and membranous nephropathy is occasionally reported. Pathogenic mechanisms are unclear until now; however, auto-immune and allergic mechanisms have been suspected from laboratory data. The initial response to steroid agents is generally favorable; however, recurrence is possible after the discontinuation of steroid treatment. Long-term follow-up is necessary with continuous systemic checks for organ disorders due to IgG4-related systemic diseases.     

Proposal for diagnostic criteria for IgG4-related kidney disease

Background

IgG4-related disease has attracted wide attention recently. It is characterized by a high level of serum IgG4 and dense infiltration of IgG4-positive plasma cells into multiple organs, with the kidney being one representative target. Although several sets of diagnostic criteria for autoimmune pancreatitis (AIP) are available and renal lesion is recognized as an extra-pancreatic manifestation of AIP, it is difficult to differentiate IgG4-related tubulointerstitial nephritis (TIN) without AIP from other types of TIN. To clarify the entity of IgG4-related kidney disease (IgG4-RKD) and support in-depth studies, the Japanese Society of Nephrology has established a working group to prepare diagnostic criteria for IgG4-RKD.

Method

The working group analyzed 41 patients with IgG4-RKD, and collected the following data to devise a diagnostic algorithm and diagnostic criteria for IgG4-RKD: clinical features including extra-renal organ involvement, urinalysis and serological features including serum IgG4 levels, imaging findings demonstrated by computed tomography (CT), renal histology with IgG4 immunostaining, and response to steroid therapy.

Results

The conditions for criteria are as follows. (1) Presence of some kidney damage, as manifested by abnormal urinalysis or urine marker(s) and/or decreased kidney function with either elevated serum IgG level, hypocomplementemia, or elevated serum IgE level. (2) Kidney imaging studies showing abnormal renal imaging findings, i.e., multiple low density lesions on enhanced CT, diffuse kidney enlargement, hypovascular solitary mass in the kidney, and hypertrophic lesion of the renal pelvic wall without irregularity of the renal pelvic surface. (3) Serum IgG4 level exceeding 135?mg/dl. (4) Renal histology showing two abnormal findings: (a) dense lymphoplasmacytic infiltration with infiltrating IgG4-positive plasma cells >10/high power field (HPF) and/or ratio of IgG4-positive plasma cells/IgG positive plasma cells >40%. (b) Characteristic ??storiform?? fibrosis surrounding nests of lymphocytes and/or plasma cells. (5) Extra-renal histology showing dense lymphoplasmacytic infiltration with infiltrating IgG4-positive plasma cells >10/HPF and/or ratio of IgG4-positive plasma cells/IgG-positive plasma cells >40%. The diagnosis is classified into 3 stages of definite, probable and possible according to the combinations of the above conditions. Thirty-nine cases (95.1%) were diagnosed with IgG4-RKD according to the criteria.

Conclusion

The provisional criteria and algorithm appear to be useful for clarifying the entity of IgG4-RKD and seeking underlying IgG4-RKD cases; however, further experience is needed to confirm the validity of these criteria.     

Tubulointerstitial nephritis associated with IgG4-related systemic disease

We report three patients with tubulointerstitial nephritis (TIN) with high serum IgG4 concentrations. None of the patients had notable pancreatic lesions when the TIN developed, although one had a history of autoimmune pancreatitis (AIP). Nevertheless, the clinicopathological findings were quite similar to those of AIP. They were all middle-aged to elderly men. Sialadenitis and lymphadenopathy were often evident. Serum total IgG and IgG4 concentrations were elevated and hypocomplementemia was observed. Although antinuclear antibodies were positive, anti-Ro and anti-La antibodies were negative. Renal biopsy showed dense lymphoplasmacytic infiltration with fibrosis in the renal interstitium, and the infiltrated plasma cells had strong immunoreactivity for IgG4. Furthermore, lymphoplasmacytic infiltration and abundant IgG4-positive plasma cells were observed in the salivary glands of a patient. Steroid therapy was effective for TIN in all three patients. The present findings support the recently proposed concept of IgG4-related systemic disease, and suggest that IgG4 is associated not only with AIP but also with other systemic lymphoplasmacytic diseases, including TIN. The conditions responsible for the pathogenesis of TIN need to be considered, irrespective of the presence of AIP.     

Recurrent IgG4‐related tubulointerstitial nephritis concurrent with chronic active antibody mediated rejection: A case report

IgG4‐related disease is a relatively newly described entity that can affect nearly any organ, including the kidneys, where it usually manifests as tubulointerstitial nephritis (IgG4‐TIN). The diagnosis can be suggested by characteristic histological features, including an inflammatory infiltrate with increased IgG4‐positive plasma cells associated with “storiform” fibrosis. Serum IgG4 is usually elevated. In the native kidney and other organs, there is typically a brisk response to treatment with immunosuppression. Recurrence of IgG4‐TIN after renal transplant has not been described in the literature. Here, we describe the first case of recurrent IgG4‐TIN in a young patient concomitant with chronic active antibody mediated rejection five years after kidney transplant. Recurrent IgG4‐TIN could be diagnosed by the characteristic histopathologic features and increased IgG4‐positive plasma cells. Despite maintenance immunosuppression, this disease may recur in the kidney allograft.     

Endocapillary proliferative glomerulonephritis with crescent formation and concurrent tubulointerstitial nephritis complicating retroperitoneal fibrosis with a high serum level of IgG4

Renal lesions of IgG4-related disease have been reported recently. Most of them are tubulointerstitial nephritis, and a definite glomerulonephritis complicating IgG4-related disease is very rare. We report here a case of definite glomerulonephritis and concurrent tubulointerstitial nephritis complicating retroperitoneal fibrosis with a high serum level of IgG4. A 68-year-old Japanese woman was referred to our hospital for investigation of anasarca. We diagnosed her disease as a nephrotic syndrome and left hydroureteronephrosis due to retroperitoneal fibrosis. Her laboratory data revealed a high serum level of IgG4, renal injury, hypoproteinemia, hypocomplementemia, a positive finding of circulating immunocomplex (CIC), and negative findings ofautologous antibodies suggesting systemic lupus erythematosus (SLE) or Sj?gren's syndrome (SS). A diagnosis of SLE or SS could not be made clinically. Right renal biopsy revealed endocapillary proliferative glomerulonephritis with crescent formation and concurrent tubulointerstitial nephritis. Infiltration of plasma cells in interstitium was more conspicuous than seen with ordinary tubulointerstitial nephritis, and in most of them IgG4 was positive. We placed a percutaneous nephrostomy catheter in her left kidney, and prescribed prednisolone and cyclosporine. The responses to prednisolone and cyclosporine therapies were very good. Further studies are needed to clarify the relationship between glomerulonephritis and IgG4-related disease. However, when considering renal lesions of IgG4-related disease, we think that hypocomplementemia, a positive finding of CIC, negative findings of autologous antibodies suggesting SLE or SS, conspicuous interstitial infiltration of IgG4-positive plasma cells, and a good response to steroid or immunosuppressant therapy are key points.     

IgG4相关性肾病的临床病理特征分析

目的探究本中心中国人群IgG4相关性肾病的发病情况、临床病理特征及预后。 方法回顾性分析2010年1月至2019年1月在东部战区总医院国家肾脏疾病临床医学研究中心行肾穿刺活检患者的临床病理资料，对肾组织中有大量浆细胞浸润的患者，重新测定肾活检时血清IgG4水平及肾组织IgG4阳性浆细胞浸润数目，结合肾外表现，筛选出确诊为IgG4相关性肾病的病例，并分析IgG4相关性肾病的临床特点、病理特征及肾脏预后。 结果44 784例肾活检患者中有22例确诊为IgG4相关性肾病。IgG4相关性肾病最常表现为蛋白尿(86.4%)及肾功能不全(81.8%)，约68.2%患者存在肾外累及。高IgG血症、高IgG4血症、低补体血症的发生率分别为86.4%、84.2%、45.5%。肾脏组织学最常见的病理类型为IgG4相关间质性肾炎(90.9%)，其次为膜性肾病(13.6%)。肾间质席纹状纤维化、鸟眼样改变分别占40.9%、54.5%。22例患者中，21例接受糖皮质激素治疗，2例失访，余20例中位随访时间为12个月，9例肾功能好转，10例肾功能平稳，1例肾功能减退并进展至终末期肾病。 结论IgG4相关性肾病发病率低，好发于中老年男性，最常表现为肾功能不全及蛋白尿。半数以上的患者有肾外表现。高IgG血症、高IgG4血症和低补体血症是其血清学特征。最常见的肾脏病理类型为间质性肾炎；大量IgG4阳性浆细胞浸润、肾间质席纹状纤维化或鸟眼样改变是其典型的病理特征。糖皮质激素仍是IgG4相关性肾病治疗首选的一线药物。     

A case of Mikulicz’s disease complicated with severe interstitial nephritis associated with IgG4

A 48-year-old woman who had bilateral swelling in the eyelids and submandibular region was admitted. Clinical findings suggested that her renal function had deteriorated. Laboratory data showed renal insufficiency (2.52 mg/dl), hypergammaglobulinemia (IgG 3,729 mg/dl, IgA 124 mg/dl, IgM 73 mg/dl). Gallium-67 scintigram indicated abnormal uptake in bilateral lacrimal glands, submandibular glands, and kidneys. A diagnosis of Mikulicz’s disease and interstitial nephritis was made, since biopsy specimens of her lacrimal gland and minor salivary gland showed diffuse infiltration of lymphocytes. In addition, renal biopsy specimens showed diffuse severe interstitial infiltration of IgG4-positive mononuclear cells. Symptoms and laboratory data normalized in response to methylprednisolone semi-pulse therapy and prednisolone 50 mg/day. Mikulicz’s disease was recently reported to be IgG4 associated disease. In our case, Mikulicz’s disease complicated with diffuse severe interstitial nephritis was successfully treated by corticosteroid. The present case supports the hypothesis that IgG4-related autoimmune disease could be causes of Mikulicz’s disease and interstitial nephritis.     

Perirenal capsule involvement in IgG4-related chronic interstitial nephritis: a case report and literature review

Objective To explore the clinicopathological features and the renal biopsy process of a case of IgG4-related chronic interstitial nephritis with perirenal capsule involved and review associated literature to improve the clinician's understanding for this disease and to perform a better renal biopsy. Methods The onset, diagnosis and treatment course of the disease were described and associated literature were reviewed to summary the clinicopathologic features and key points in renal biopsy. Results The data of the patient showed that the urine specific gravity was 1.011, with urine protein ± and urine sugar 3+. The concentration of hemoglobin was 53 g/L, serum creatinine was 1665 μmol/L, and IgG4 was 9.39 g/L. Computed tomography showed that both kidneys enlarged slightly with decreased density and low density shadow around the kidneys. On contrast-enhanced scan, irregular low-density enhancement areas were found in both kidneys, and the edge of the boundary was not clear. For the first renal biopsy, no renal parenchyma was found except mainly hyaline collagen fibrils. At the second time, 3 pieces of tissues were obtained, which showed chronic interstitial glomerulonephritis. The IgG4 positive plasma cells were about 60/HPF and the IgG4+/IgG+cells ratio was more than 40%. The diagnosis of IgG4-related chronic interstitial glomerulonephritis was confirmed. After corticosteroid treatment, the serum creatinine decreased to 502 μmol/L after the patient got rid of dialysis. Conclusions There are various manifestations of renal damage caused by IgG4-related disease. It is necessary to pay attention to the involvement of the perirenal capsule, and to balance the risk of bleeding and poor sampling in renal biopsy.     

IgG4相关性疾病泌尿系统损害分析

目的 总结IgG4相关性疾病泌尿系统损害的临床特点,以其提高对该疾病的认识.方法 回顾性分析出现泌尿系统损害的IgG4相关性疾病患者6例的临床表现、实验室检查、影像学资料、病理表现、治疗及预后情况.结果 诊断为IgG4相关性疾病患者中6例存在泌尿系统损害,男女比例为4:2,中位年龄59岁(36～ 72岁),中位病程为10.5个月.除肾脏、输尿管受累外,所有患者均同时存在泌尿系统外的多器官受累.泌尿系统损害临床表现多样,包括肾功能异常、水肿和腹痛.所有患者均存在高球蛋白血症、血清IgG(中位值23.3 g/L)及IgG4亚型(中位值4227.0 mg/L)升高,肾小管源性蛋白尿;5例患者Scr明显升高(中位值237 μmol/L).影像学表现可分为4类:肾脏弥漫增大、CT多发低密度灶可伴不均匀强化灶、肾盂和(或)输尿管积水、肾脏萎缩.肾脏病理显示为弥漫纤维化伴肾间质大量淋巴细胞、浆细胞浸润的间质性肾炎表现,伴淋巴细胞、浆细胞IgG4免疫组化染色阳性.患者对中至大剂量糖皮质激素治疗反应良好,经治疗,临床症状改善,IgG、IgG4及Scr均明显降低.结论 IgG4相关性疾病泌尿系统损害临床表现多样化,多同时合并其他器官受累;肾组织病理学以IgG4阳性的淋巴细胞和浆细胞浸润的间质性肾炎为其突出特点;糖皮质激素治疗有效.     

Inflammatory abdominal aortic aneurysm: close relationship to IgG4-related periaortitis

Inflammatory abdominal aortic aneurysm (AAA) is a member of a family of disorders referred to as "chronic periaortitis" together with retroperitoneal fibrosis. Retroperitoneal fibrosis is included in IgG4-related disease, which is characterized by numerous infiltrating IgG4-positive plasma cells and high serum IgG4 concentrations. However, the relationship between IgG4-related disease and inflammatory AAA has not been documented. In this study, we examined the clinicopathologic characteristics of inflammatory (10 cases) and atherosclerotic (22 cases) AAAs, based on the hypothesis that inflammatory AAA might be related to IgG4-related disease. Cases of inflammatory AAA could be classified into 2 groups based on immunostaining of IgG4. Four patients showed diffuse infiltration of abundant IgG4-positive plasma cells (IgG4-related cases), whereas the remaining 6 cases of inflammatory AAA and all cases of atherosclerotic AAA had only a few IgG4-positive plasma cells (non-IgG4-related cases). IgG4-related inflammatory AAA was pathologically characterized by the frequent infiltration of eosinophils, lymph follicle formation, perineural inflammatory extension, and inconspicuous infiltration of neutrophils compared with non-IgG4-related inflammatory AAA. Obliterative phlebitis, which is venous occlusion with inflammatory cell infiltration, is observed in all IgG4-related cases. In addition, serum IgG4 concentrations were significantly higher in IgG4-related inflammatory AAA (109 to 559 mg/dL, normal range: 4 to 110 mg/dL) than non-IgG4-related inflammatory AAA (32 to 59 mg/dL) and all atherosclerotic AAA (12 to 83 mg/dL). In conclusion, inflammatory AAAs might be classified into 2 groups: IgG4-related or nonrelated. The former might be one of the IgG4-related diseases, and could be included in IgG4-related periaortitis together with retroperitoneal fibrosis.     

Tubulointerstitial nephritis in active tuberculosis - a single center experience

Background: Tuberculosis (TB) is a common disease worldwide, but kidney affection, i.e. tubulointerstitial nephritis (TIN) caused by Mycobacterium tuberculosis is rare. More frequent in patients with TB is drug induced TIN, i.e. the result of intensive antitubercular treatment. Patients and methods: In the time between April 2005 until August 2011 data from all patients (4 male, 1 female) with clinical evidence of active TB and significant renal disease were collected. All patients were treated with antitubercular treatment according to standard protocols. All patients underwent kidney biopsy due to progressive renal failure and all of the renal biopsies revealed an interstitial inflammation with eosinophilia. Epitheloid granulomata were found in 3 of 5 patients, whereas caseating granulomata were found in only one patient. No patient had sterile leucozyturia and all patients were negative for Mycobacterium tuberculosis on PCR; of note, none of the renal biopsies examined were positive for acid and alcohol fast bacilli by Ziehl-Neelsen staining. Conclusions: TB associated TIN is rare, but needs a rapid recognition and an early treatment. Kidney biopsy should be performed in patients with TB and renal disease to ensure the diagnosis of renal involvement of active TB and established correct treatment (intensifying TB treatment or changing TB therapy in drug induced TIN). Additionally, negative PCR of the histopathological samples should not exclude TB associated TIN and sterile leukocyturia is less common than expected.     

IgG4-Related Cholecystitis Presenting as Biliary Malignancy: Report of Three Cases

An increased awareness of IgG4-related diseases has led to an escalation in the number of sites known to be involved by this fibroinflammatory disease. We report three cases of IgG4-related cholecystitis which were thought to represent biliary malignancies both clinically and radiographically. All three cases underwent surgery tailored towards presumed malignant neoplasms. Only following pathologic examination was the true nature of the disease identified. Recognition of the clinical, radiographic, and pathologic presentation of IgG4-related cholecystitis is essential for the consideration of this disease process prior to surgical management for suspected gallbladder malignancies. However, the pre-operative diagnosis remains challenging and extensive surgical intervention is often necessary given the distressing presentation of IgG4-related cholecystitis.     

Lymphadenopathy of IgG4-related sclerosing disease

IgG4-related sclerosing disease is a recently recognized syndrome characterized by mass-forming lesions in exocrine glands or extranodal tissues due to lymphoplasmacytic infiltrates and sclerosis, a raised serum IgG4 level and increased IgG4+ plasma cells in the involved tissues. We report the morphologic features of the enlarged regional (n=3) and nonregional lymph nodes (n=3) in patients with this syndrome. The patients presented with autoimmune pancreatitis, lymphoplasmacytic sclerosing cholangitis, chronic sclerosing dacryoadenitis, or chronic sclerosing sialadenitis. The histologic features of the lymph nodes could be categorized into 3 patterns: Castleman diseaselike, follicular hyperplasia, and interfollicular expansion by immunoblasts and plasma cells. The percentage of IgG4+/IgG+ plasma cells was markedly elevated (mean 62% vs. 9.9% in 54 control lymph nodes comprising a wide variety of reactive conditions). We also report 6 cases of primary lymphadenopathy characterized by increased IgG4+/IgG+plasma cells (mean 58%). These cases share many clinical and pathologic similarities with IgG4-related sclerosing disease. In fact, 2 of these patients developed lymphoplasmacytic sclerosing cholangitis or lacrimal and submandibular gland involvement during the clinical course. These cases therefore probably represent primary lymph node manifestation of the disease. The importance of recognition of the lymphadenopathic form of IgG4-related sclerosing disease lies in the remarkable response to steroid therapy, and the potential of mistaking the disease for lymphoma either clinically or histologically.     

Pathologic evaluation of non-neoplastic renal parenchyma in partial nephrectomy specimens

Purpose

This study aimed to identify non-neoplastic pathologic changes in partial nephrectomy specimens of patients without a known history of medical comorbidities. Routine analysis of this tissue may allow the clinician to identify subclinical renal disease.

Methods

We retrospectively reviewed our database of patients who underwent open partial nephrectomy for a small renal mass. Non-neoplastic tissue of partial nephrectomy specimens of patients without a known history of chronic kidney disease, diabetes mellitus, hypertension, or coronary artery disease was evaluated for glomerular, interstitial, and vascular pathologic changes.

Results

A rim of non-neoplastic tissue was adequate for pathologic evaluation in 91.8% of specimens. A total of 45 patients were studied with a median age of 52.0 years. Atherosclerosis was the most commonly identified pathologic finding in 9 (20%) patients, followed by mesangial expansion and interstitial fibrosis, each found in 8 (17.8%) patients. Linear regression found interstitial fibrosis to be the only pathologic lesion associated with preoperative serum creatinine (coefficient = 0.697, P = 0.001). Male gender was also associated with a higher preoperative creatinine (coefficient = 0.270, P = 0.034). Postoperative serum creatinine was not associated with any of the examined lesions.

Conclusions

Current surgical techniques provide adequate non-neoplastic tissue for pathologic evaluation. We observed a striking degree of pathologic disease in patients without a known history of medical comorbidities. Routine inspection of the non-neoplastic parenchyma of partial nephrectomy specimens should be performed as it can alert the clinician to presence subclinical renal disease allowing for medical intervention.     

Autoimmune pancreatitis: a systemic immune complex mediated disease

Autoimmune pancreatitis (AIP) is a mass forming inflammatory pancreatobiliary-centric disease. Recent reports of multiorgan inflammatory mass forming lesions with increased numbers of IgG4 positive plasma cells suggest that AIP may have a systemic component. In this study, we explore the systemic nature of AIP, investigate the relevance of subtyping AIP, perform a systematic study of tissue IgG4 immunoperoxidase, and ultrastructurally evaluate the presence of immune complexes. Our study group consisted of 36 patients with AIP, 21 of whom underwent a Whipple procedure. On the basis of the pattern of inflammation, pancreatic involvement was subtyped as ductocentric (AIP-D) or lobulocentric (AIP-L). Extrapancreatic lesions included bile duct (n=3), salivary glands (n=3), lung (n=2), gallbladder (n=11), and kidney (n=4). Clinical and radiologic data was recorded. Immunohistochemistry for IgG4 was performed on both pancreatic and extrapancreatic tissues and the numbers of IgG4 positive plasma cells were semiquantitatively scored. A control cohort composed of pancreatic adenocarcinoma (n=19) and chronic pancreatitis-not otherwise specified (NOS) (n=14) was also evaluated. Eleven pancreatic specimens, including 2 cases of chronic pancreatitis-NOS and 4 kidneys were evaluated ultrastructurally. The pancreas, bile duct, gall bladder, salivary gland, kidney, and lung lesions were characterized by dense lymphoplasmacytic infiltrates with reactive fibroblasts and venulitis. IgG4 positive plasma cells were identified in all pancreatic and extrapancreatic lesions. The AIP cases showed significantly more pancreatic IgG4 positive plasma cells than chronic pancreatitis-NOS or adenocarcinoma (P=0.001). However, IgG4 positive cells were identified in 57.1% of chronic pancreatitis-NOS and 47.4% of ductal adenocarcinoma. Fifteen of 21 resected cases were classified as AIP-D, and 6 as AIP-L, the latter notably showing significantly more IgG4 positive plasma cells than the former (P=0.02). Additionally, clinical and radiologic differences emerged between the 2 groups. Ultrastructurally, electron dense deposits of immune complexes were identified in the basement membranes of 7 of the 9 AIP cases and in 3 of the 4 renal biopsies evaluated. AIP represents the pancreatic manifestation of a systemic autoimmune disease. Clinical and immunologic findings justify the recognition of pancreatic lobulocentric and ductocentric subtypes. Documentation of increased numbers of tissue IgG4 positive plasma cells, although not an entirely specific marker for AIP, may provide ancillary evidence for the diagnosis of a IgG4-related systemic disease.