Renal granulomatous sarcoidosis in childhood: a report of 11 cases and a review of the literature

Imaging Features of Pediatric Sarcoidosis

Sarcoidosis is a granulomatous inflammatory disease of uncertain cause. It occurs most commonly in young and middle-aged adults and less frequently in children; therefore, few data on pediatric sarcoidosis exist in the literature. The diagnosis and management of sarcoidosis remain challenging because of diverse and often nonspecific clinical and imaging findings. In addition, the clinical picture varies widely by age. Prepubertal and adolescent patients often present with adult-like pulmonary disease; however, early-onset sarcoidosis is typically characterized by the triad of arthritis, uveitis, and skin rash. Sarcoidosis is mostly a diagnosis of exclusion made by demonstrating noncaseating granulomas at histopathologic examination in patients with compatible clinical and radiologic findings. Although sarcoidosis often affects the lungs and thoracic lymph nodes, it can involve almost any organ in the body. The most common radiologic manifestation is pulmonary involvement, characterized by mediastinal and bilateral symmetric hilar lymphadenopathies with perilymphatic micronodules. Abdominal involvement is also common in children and often manifests as hepatomegaly, splenomegaly, and abdominal lymph node enlargement. Although neurosarcoidosis and cardiac sarcoidosis are rare, imaging is essential to the diagnosis of central nervous system and cardiac involvement because of the risky biopsy procedure and its low diagnostic yield due to focal involvement. Being familiar with the spectrum of imaging findings of sarcoidosis may aid in appropriate diagnosis and management. ©RSNA, 2023 Test Your Knowledge questions are available in the supplemental material.

The Overlap of Kidney Failure in Extrapulmonary Sarcoidosis in Children-Case Report and Review of Literature

Sarcoidosis is a non-necrotizing granulomatous inflammatory multisystemic disorder of unknown etiology. In children, as in adults, it can involve a few or all organ systems to a varying extent and degree, entailing multisystemic manifestations. Kidney involvement in pediatric-onset adult-type sarcoidosis is rare, with a wide range of renal manifestations, most of them related to calcium metabolism. Children with renal sarcoidosis tend to be more symptomatic than adults, although male patients have a higher prevalence. We present the case of a 10-year-old boy who presented with advanced renal failure with nephrocalcinosis and important hepatosplenomegaly. The diagnosis was established by histopathological examination, with consequent cortisone therapy and hemodialysis. This review emphasizes that sarcoidosis should be considered in the differential diagnosis of pediatric patients with acute kidney insufficiency or chronic kidney disease of an unknown etiology. As far as we know, this is the first study regarding extrapulmonary sarcoidosis in children from Romania.

Granulomatous nephritis: A rare presentation of juvenile-onset sarcoidosis

Sarcoidosis is rare in children. Incidence and prevalence of sarcoidosis in India are not known. Renal involvement in childhood sarcoidosis is further rare with no clear data about prevalence. Here we report a case of a 13-year-old girl who presented with sarcoidosis with multi-system involvement including renal sarcoidosis. She initially presented with pyrexia of unknown origin and cervical lymphadenopathy - evaluation of which led to diagnosis of sarcoidosis. Later, after development of pulmonary involvement, she was treated with oral prednisolone and azathioprine. She again defaulted on medicines and later presented with renal failure and was diagnosed with a renal sarcoidosis. She was treated with oral prednisolone and mycophenolate mofetil with which she gradually improved with normal renal functions.

Case Report: Pediatric Renal Sarcoidosis and Prognostic Factors in Reviewed Cases

Background: Pediatric sarcoidosis is a complex inflammatory disorder with multisystemic manifestations. Kidney involvement in children is rare, and prognostic factors are unknown. Case Report and Methods: We report the case of a 16-year-old girl with multiorgan sarcoidosis and renal involvement. The patient presented with tubulointerstitial nephritis, acute kidney injury (AKI), chest CT disseminated noduli, granulomatous iridocyclitis, giant-cell sialadenitis, and arthralgia. The kidney biopsy revealed non-granulomatous interstitial nephritis. Treatment consisted of initial high-dose methylprednisolone pulse followed by oral prednisolone and methotrexate. Full remission was achieved. In addition, we performed a literature review using PubMed and analyzed data on pediatric renal sarcoidosis cases. Results: We identified 36 cases of pediatric sarcoidosis with renal involvement on presentation and data on the end-of-follow-up glomerular filtration rate (GFR). The data from the literature review showed that renal involvement was slightly more prevalent in males (60%). AKI was present in most of the described patients (84%). Oral prednisolone was used in 35 of 36 cases; in more severe cases, other immunosuppressants were used. We newly identified renal concentration impairment and granulomatous interstitial nephritis as factors with a clear trend toward GFR loss at the end of follow-up, emphasizing the importance of kidney biopsy in symptomatic patients. In contrast, higher GFR at presentation and hypercalcemia were rather favorable factors. According to the identified predictive factors, our patient has a good prognosis and is in remission. Conclusion: The factors indicating a trend toward an unfavorable renal outcome in pediatric sarcoidosis are renal concentration impairment and granulomatous interstitial nephritis at presentation, while a higher GFR is beneficial.

Long-term outcome of biopsy-proven idiopathic tubulointersitial nephritis with or without uveitis in children-a nationwide follow-up study

BACKGROUND

Only a few studies reporting the long-term outcome of children with idiopathic tubulointerstitial nephritis (TIN) and uveitis syndrome (TINU) are available. We studied the long-term kidney and ocular outcome in a nationwide cohort of children with TIN or TINU.

METHODS

All patients followed up for a minimum of 1 year by a paediatrician and an ophthalmologist were enrolled. The data on plasma creatinine (P-Cr), estimated glomerular filtration rate (eGFR), proteinuria, hypertension and uveitis were collected retrospectively.

RESULTS

Fifty-two patients were studied. Median age at time of diagnosis was 13.1 (1.8-16.9) years and median follow-up time was 5.7 (1.1-21.2) years. Forty-five (87%) patients were initially treated with glucocorticoids. The median of the maximum P-Cr was 162 μmol/l (47-1,016) and that of eGFR 47 ml/min/1.73m² (8-124). Uveitis was diagnosed in 33 patients (63%) and 21 (40%) patients developed chronic uveitis. P-Cr normalised in a median of 2 months. Eleven (21%) patients had nephritis recurrence during or after discontinuation of glucocorticoids. At the latest follow-up, 13 (25%) patients had eGFR < 90 ml/min/1.73m² (median 83; 61-89 ml/min/1.73m²). Six patients had tubular proteinuria; all presented with TIN without uveitis. Seven (13%) patients were hypertensive. Eleven (21%) patients had uveitis. One patient developed uraemia and was later transplanted.

CONCLUSIONS

Our study questions the previously reported good long-term kidney and ocular outcome of patients with TIN/TINU. Decreased kidney function and/or ocular co-morbidities may persist for several years; thus, both kidney and ocular follow-up for at least 1 year is warranted. A higher resolution version of the Graphical abstract is available as Supplementary information.

Renal sarcoidosis: approach to diagnosis and management

PURPOSE OF REVIEW

The purpose of this article is to provide understanding of renal sarcoidosis, the different types of renal sarcoidosis, disease burden of renal involvement, and treatment options.

RECENT FINDINGS

The frequency of renal involvement seems to be underestimated, but renal sarcoidosis represents a relevant group of organ manifestations and significantly adds to the patient's morbidity. Because histopathological analysis of renal biopsy specimens can reveal various entities, a diagnostic workup is necessary in every patient with sarcoidosis.

SUMMARY

If systematically screened for renal manifestations are likely to occur in up to 25-30% of all sarcoidosis patients. The most common histological form of renal sarcoidosis is the granulomatous interstitial nephritis; however, granulomas can be absent. Furthermore, one can find various forms of secondary glomerulonephritis. In cases with dysregulated calcium homeostasis, nephrocalcinosis and nephrolithiasis are commonly detectable kidney diseases. AA amyloidosis or renal masses because of granuloma formation are considered to be rare manifestations. In addition to glucocorticoids various immunosuppressive treatments such as tumor necrosis factor alpha inhibitors have proven to be effective based on case series.

IL-10 polymorphisms +434T/C, +504G/T, and -2849C/T may predispose to tubulointersititial nephritis and uveitis in pediatric population

BACKGROUND

Tubulointerstitial nephritis (TIN) and uveitis syndrome (TINU) are likely to be autoimmune diseases. Based on previous studies, adults with isolated idiopathic uveitis have polymorphisms in interleukin 10 (IL-10) and tumor necrosis factor α (TNF-α) genes. We aimed to evaluate the presence of IL-10 and TNF-α polymorphisms in a nationwide cohort of pediatric TIN/TINU patients.

METHODS

Single nucleotide polymorphisms in IL-10 (+434T/C, +504G/T, -1082G/A, -2849C/T) and in TNFα (-308G/A, -238G/A, -857C/T) genes were genotyped in 30 well-defined pediatric patients with idiopathic TIN/TINU syndrome. Control group frequencies for these SNPs were obtained from 393 independent Finnish subjects.

RESULTS

The homozygous minor allele in IL-10 +434T (rs2222202) and IL-10+504G (rs3024490) was found in all patients with TIN or TINU syndrome while the frequency of these minor alleles in the control population was 44% and 23%, respectively (p <0.001). In IL-10 SNP -2849 (rs6703630) a significant difference was found with genotype TT in all patients (p = 0.004) and in subgroups with TINU syndrome (p = 0.017) and TINU syndrome with chronic uveitis (p = 0.01) compared to reference population. There were no statistical differences in any of the studied TNF-α genotypes between TIN/TINU patients and control population.

CONCLUSIONS

A significant difference in the frequency of IL-10+434T and +504G alleles was found between TIN/TINU patients and control population. Genotype -2849TT was more frequently present in patients with TINU syndrome than in the reference subjects. Genetic variation in the inflammatory mediators may predispose to autoimmune nephritis and uveitis.

Acute kidney injury as a rare manifestation of pediatric sarcoidosis: A case report and systematic literature review

BACKGROUND

Sarcoidosis is a chronic noncaseating granulomatous disease with an unknown etiology that can affect multiple organs. Renal involvement in pediatric-onset adult-type sarcoidosis is rare, and only a few cases have been reported. We present a case of a Chinese patient with pediatric-onset adult-type sarcoidosis with renal involvement, and a literature review was performed.

METHODS

The PubMed database was searched for publications, and relevant clinical data were extracted and presented.

RESULTS

We identified 22 pediatric-onset adult-type sarcoidosis cases with renal involvement. Acute kidney injury was the major clinical presentation. Granulomatous interstitial nephritis was the predominant histopathological feature. All patients were treated with corticosteroids and immunosuppressive agents, and most achieved improved outcome.

CONCLUSIONS

Sarcoidosis should be considered in children with acute kidney injury of an unknown etiology. A final diagnosis is established through a combination of the clinical and laboratory characteristics, radiological presentation, and histological features of noncaseating granulomas. A therapeutic schedule should be decided after a systemic assessment.

A curious case of growth failure and hypercalcemia: Answers

BACKGROUND

Sarcoidosis is a multisystem granulomatous disease of unknown etiology that rarely presents in childhood. Here, we report a case of pediatric sarcoidosis, presenting with renal failure and hypercalcemia.

CASE DIAGNOSIS/TREATMENT

A previously well 14-year-old Caucasian boy was admitted to the Hospital for Sick Children, Canada, for hypertension and renal failure following work-up by his family physician for initial concerns of growth failure. On admission, his weight was 35 kg (<3rd percentile), his height was 148 cm (<<3rd percentile), and his blood pressure was 154/116 mmHg (>99th percentile for height). Laboratory findings showed elevated creatinine (218 umol/L), hypercalcemia (3.21 mmol/L), and normocytic anemia (hemoglobin 105 g/L). His further assessment showed a urinary concentrating defect with hypercalciuria (calcium/creatinine 1.76 mmol/mmol) and nephrocalcinosis on ultrasound. His eye examination showed uveitis with conjunctival biopsy remarkable for granulomas, which led to pursuit of a diagnosis of possible sarcoidosis. Angiotensin Angiotensin-converting enzyme was found to be high at 96 U/L, and he had a renal biopsy that was consistent with interstitial nephritis with granulomas. Treatment was started with prednisone leading to resolution of his hypercalcemia but persistence of his mild chronic kidney disease.

CONCLUSIONS

This case represents an atypical presentation of a rare pediatric disease and highlights the spectrum of renal manifestations and treatment options in sarcoidosis.

Granulomatous inflammation: The overlap of immune deficiency and inflammation

Pediatric granulomatous diseases constitute a heterogenous group of conditions in terms of clinical phenotypes, pathogenic mechanisms, and outcomes. The common link is the presence of multinucleated giant cells in the inflammatory infiltrate. The clinical scenario in which a tissue biopsy shows granulomatous inflammation is not an uncommon one for practicing adult and pediatric rheumatologists. Our role as rheumatologists is to develop a diagnostic plan based on a rational differential diagnostic exercise tailored to the individual patient and based mainly on a detailed clinical assessment. This chapter presents a comprehensive differential diagnosis associated with a classification developed by the authors. We describe with some detail extrapulmonary sarcoidosis, Blau syndrome, and immunodeficiency associated granulomatous inflammation, which in our view are the paradigmatic primary forms of granulomatous diseases in childhood. The other entities are presented only as differential diagnoses listing their most relevant clinical features. This chapter shows that almost all granulomatous diseases seen in adults can be found in children and that there are some entities that are essentially pediatric at onset, namely Blau syndrome and most forms of immunodeficiency associated granulomatous diseases.

The diversity of juvenile sarcoidosis symptoms

We report a case of juvenile sarcoidosis, emphasizing the variety of clinical manifestations. The child had uveitis, which is among the most common manifestations of the disease. However, fever of unknown origin, glomerulonephritis and lymphadenopathy were also noticed, underscoring the diversity of the clinical spectrum of the disease.

Budd-Chiari syndrome as presenting symptom of hepatic sarcoidosis in a child, with recurrence after liver transplantation

A seven-yr-old boy presented with a severe Budd-Chiari syndrome, complicated by recurrent thrombosis of several successive TIPSs. Because of liver failure secondary to venous outflow tract obstruction and deterioration of his general condition, an emergency liver transplantation was performed. Steroids were discontinued three months after transplantation, and maintenance immunosuppressive therapy consisted of tacrolimus and azathioprine. Seven years later, this patient presented symptoms of recurrence of venous outflow obstruction in the transplant liver, comparable to the initial event. Histopathology of the liver revealed diffuse granulomatous inflammation with confluent non-caseating granulomas compressing the centrolobular veins. Extensive investigations excluded infections, immune deficiency, and systemic vasculitides. After treatment with a high dose of corticosteroids, the granulomas in the allograft disappeared completely. We report the first case of hepatic sarcoidosis, presenting with venous outflow obstruction and recurring after liver transplantation, in a child.

The puzzling clinical spectrum and course of juvenile sarcoidosis

BACKGROUND

Juvenile sarcoidosis is a rare, chronic, multisystem, granulomatous disease of obscure etiology which is seen in childhood and adulthood. The disease in childhood has a course different from that in adulthood.

DATA SOURCES

PubMed database was searched using terms sarcoidosis, children or childhood sarcoidosis or juvenile sarcoidosis in combination with one of the following terms: epidemiology, clinical manifestations, genetics, diagnosis, treatment, and prognosis. We also retrieved the terms such as early onset sarcoidosis and Blau syndrome. Furthermore, e-medicine and European Respiratory Society monographs for sarcoidosis were reviewed.

RESULTS

Sarcoidosis in childhood presents with two age dependent, distinct forms. In younger children it is clinically evident before the age of four years and characterized by the triad of rash, arthritis and uveitis. In their older counterparts, the juvenile late onset sarcoidosis involves several organs and its clinical appearance resembles the adult type of the disease, with the respiratory system being most frequently affected (hilar lymphadenopathy, pulmonary infiltrations). Steroid is the main agent of treatment whereas methotrexate is also used for beneficial steroid sparing effects. New, novel therapies may change the outcome of the disease especially in difficult morbid cases.

CONCLUSIONS

Sarcoidosis in childhood is recognized as a systemic disease affecting various organs and having diverse clinical course depending on the age of onset.

Unusual presentation of sarcoidosis in a child

Sarcoidosis is a chronic multisystemic granulomatous disease of unknown etiology. We report a 5-year-old boy with sarcoidosis who had an unusual presentation of membranous nephropathy and Budd-Chiari syndrome. These combinations of features have never reported in pediatric literature so far.

Recurrence of granulomatous interstitial nephritis in transplanted kidney

Sarcoidosis is a multisystemic disease of unknown etiology. Minor renal involvement is not rare but kidney failure is uncommon and only rare cases of recurrent disease in a kidney transplant have been published. We report a patient who at age 10 yr developed ESRD secondary to renal sarcoidosis with GIN. Her disease subsequently recurred in the transplanted kidney despite standard immunosuppression with prednisone, tacrolimus, and mycophenolate mofetil. The recurrent disease appeared to respond to increased immunosuppression, which included infliximab. However, the patient died of disseminated histoplasmosis three yr post-transplant.

NOD2-associated pediatric granulomatous arthritis, an expanding phenotype: study of an international registry and a national cohort in Spain

OBJECTIVE

To study the phenotype characteristics of the largest to date cohort of patients with pediatric granulomatous arthritis (PGA) and documented mutations in the NOD2 gene.

METHODS

We analyzed merged data from 2 prospective cohorts of PGA patients, the International PGA Registry and a Spanish cohort. A systematic review of the medical records of interest was performed to identify phenotype characteristics.

RESULTS

Forty-five patients with PGA (23 sporadic cases and 22 from familial pedigrees) and documented NOD2 mutations were identified and formed the basis of the study. Of these 45 patients, 18 had the R334W-encoding mutation, 18 had R334Q, 4 had E383K, 3 had R587C, 1 had C495Y, and 1 had W490L. The majority of patients manifested the typical triad of dermatitis, uveitis, and arthritis. In contrast, in 13 patients, the following "atypical" manifestations were noted: fever, sialadenitis, lymphadenopathy, erythema nodosum, leukocytoclastic vasculitis, transient neuropathy, granulomatous glomerular and interstitial nephritis, interstitial lung disease, arterial hypertension, hypertrophic cardiomyopathy, pericarditis, pulmonary embolism, hepatic granulomatous infiltration, splenic involvement, and chronic renal failure. In addition, 4 individuals who were asymptomatic carriers of a disease-causing mutation were documented.

CONCLUSION

NOD2-associated PGA can be a multisystem disorder with significant visceral involvement. Treating physicians should be aware of the systemic nature of this condition, since some of these manifestations may entail long-term morbidity.

Renal sarcoidosis: clinical, laboratory, and histologic presentation and outcome in 47 patients

We conducted the current study to investigate the clinical, laboratory, and histologic features at presentation and the outcome of renal sarcoidosis (RS). Exhaustive retrospective data were collected by the French Sarcoidosis Group. Forty-seven adult patients were assessed (30 male/17 female, M/F ratio: 1.76). Median estimated glomerular filtration rate (eGFR) was 20.5 mL/min per 1.73 m(2) (range, 4-93 mL/min per 1.73 m(2)). Moderate proteinuria was found in 31 (66%) patients (median, 0.7 g/24 h; range, 0-2.7 g/24 h), microscopic hematuria in 11 (21.7%) patients, aseptic leukocyturia in 13 (28.7%) patients. Fifteen of 47 (32%) patients had hypercalcemia (>2.75 mmol/L). Eleven of the 22 (50%) patients diagnosed between June and September had hypercalcemia compared with only 4 of the 25 (16%) cases diagnosed during the other months (p < 0.001). Thirty-seven patients presented with noncaseating granulomatous interstitial nephritis (GIN), and 10 with interstitial nephritis without granulomas. Apart from hypercalcemia, the clinical phenotype was also remarkable for the high frequency of fever at presentation. All patients initially received prednisone (median duration, 18 mo), 10 received intravenous pulse methylprednisolone. eGFR increased from 20 +/- 19 to 44 +/- 24.7 mL/min per 1.73 m(2) at 1 month (p < 0.001, n = 38), to 47 +/- 19.9 mL/min per 1.73 m(2) at 1 year (p < 0.001, n = 46), to 49.13 +/- 25 mL/min per 1.73 m(2) at last follow-up (p < 0.001, n = 47). A complete response to therapy at 1 year and at last follow-up was strongly correlated with complete response at 1 month (p < 0.01). Renal function improvement was inversely related to initial histologic fibrosis score. A complete response to therapy at 1 year was strongly correlated with hypercalcemia at presentation (p = 0.003). Relapses were purely renal (n = 3) and purely extrarenal (n = 10) or both (n = 4), often a long time after presentation, with in some cases severe cardiac or central nervous system involvement. We conclude that hypercalcemia and fever at presentation are often associated with RS; RS is most often and permanently responsive to corticosteroid treatment, but some degree of persistent renal failure is highly frequent and its degree of severity in the long run is well predicted from both histologic fibrotic renal score and response obtained at 1 month.

Mizoribine for renal sarcoidosis: effective steroid tapering and prevention of recurrence

Sarcoidosis is a systemic disease of unknown etiology that is characterized by chronic non-caseating granulomatous inflammation with tissue destruction. It is an uncommon disease in children, and renal sarcoidosis in particular is very rare in adults and children. A 17-year-old boy with renal sarcoidosis was referred to our hospital with an initial diagnosis of pyelonephritis. Prior treatment with various antibiotics had not been effective, but tentative oral daily prednisolone (PSL) had partially ameliorated his symptoms, although the symptoms recurred during steroid tapering. We detected non-caseating granulomatous interstitial nephritis and numerous sclerotic glomeruli in a second biopsy specimen, compatible with the diagnosis of renal sarcoidosis. The patient was treated with pulsed methyl-prednisolone and oral daily doses of PSL and mizoribine (MZR). During the treatment with MZR, the PSL was successfully tapered, and the patient has since presented no signs of recurrence. Our treatment of this patient shows that treatment with MZR can allow steroid sparing and prevent recurrence in a patient with sarcoidosis.

Childhood sarcoidosis: A rare but fascinating disorder

Childhood sarcoidosis is a rare multisystemic granulomatous disorder of unknown etiology. In the pediatric series reported from the southeastern United States, sarcoidosis had a higher incidence among African Americans. Most reported childhood cases have occurred in patients aged 13-15 years. Macrophages bearing an increased expression of major histocompatibility class (MHC) II molecules most likely initiate the inflammatory response of sarcoidosis by presenting an unidentified antigen to CD4+ Th (helper-inducer) lymphocytes. A persistent, poorly degradable antigen driven cell-mediated immune response leads to a cytokine cascade, to granuloma formation, and eventually to fibrosis. Frequently observed immunologic features include depression of cutaneous delayed-type hypersensitivity and a heightened helper T cell type 1 (Th1) immune response at sites of disease. Circulating immune complexes, along with signs of B cell hyperactivity, may also be found. The clinical presentation can vary greatly depending upon the organs involved and age of the patient. Two distinct forms of sarcoidosis exist in children. Older children usually present with a multisystem disease similar to the adult manifestations, with frequent hilar lymphadenopathy and pulmonary infiltrations. Early-onset sarcoidosis is a unique form of the disease characterized by the triad of rash, uveitis, and arthritis in children presenting before four years of age. The diagnosis of sarcoidosis is confirmed by demonstrating a typical noncaseating granuloma on a biopsy specimen. Other granulmatous diseases should be reasonably excluded. The current therapy of choice for sarcoidosis in children with multisystem involvement is oral corticosteroids. Methotrexate given orally in low doses has been effective, safe and steroid sparing in some patients. Alternative immunosuppressive agents, such as azathioprine, cyclophosphamide, chlorambucil, and cyclosporine, have been tried in adult cases of sarcoidosis with questionable efficacy. The high toxicity profile of these agents, including an increased risk of lymphoproliferative disorders and carcinomas, has limited their use to patients with severe disease refractory to other agents. Successful steroid sparing treatment with mycophenolate mofetil was described in an adolescent with renal-limited sarcoidosis complicated by renal failure. Novel treatment strategies for sarcoidosis have been developed including the use of TNF-alpha inhibitors, such as infliximab. The long-term course and prognosis is not well established in childhood sarcoidosis, but it appears to be poorer in early-onset disease.

[Sarcoidosis as an uncommon cause of articular pathology in pediatric patients]

We present two cases of sarcoidosis with chronic arthropathy presenting clinical and imaging findings compatible with chronic juvenile arthritis. One patient suffered from chronic nephropathy, with anomalous US pattern and sarcoid granulomas demonstrated at renal biopsy. Throughout the illness, the patient suffered from cutaneous lesions that proved to be sarcoid granulomas after biopsy. US and color-Doppler US were useful in detecting the lesions and in the follow-up of the chronic articular pathology in these children. Although sarcoidosis is uncommon, it is important to consider this disease in the diagnosis of chronic arthropathy in children. We analyze these two cases and comment on the clinical and imaging characteristics of pediatric articular sarcoidosis.

Sarcoidosis presenting with hearing loss and granulomatous interstitial nephritis in an adolescent

Granulomatous interstitial nephritis is an uncommon finding in a kidney biopsy. The differential diagnosis is broad and includes infections, drug exposure, and sarcoidosis. Sarcoidosis, a systemic disorder of unknown etiology characterized by the presence of noncaseating granulomata in affected organs, is rare in children. We discuss an adolescent boy with the unusual presentation of granulomatous interstitial nephritis and acute deafness. Sarcoidosis should be considered as part of the differential diagnosis for children and adolescents with hearing loss and kidney disease.

Successful steroid-sparing treatment of renal limited sarcoidosis with mycophenolate mofetil

Sarcoidosis is a multi-system disorder characterized by non-caseating epithelioid granulomas in multiple organs. The disease usually presents in young adults and is uncommon in children. Renal involvement can usually occur due to granulomatous interstitial nephritis, but renal failure is uncommon. Corticosteroids are the mainstay of therapy. We present the report of a child with severe renal failure secondary to renal limited sarcoidosis who was successfully treated with corticosteroid induction therapy. Because of the severe side effects of corticosteroids, mycophenolate mofetil was added and corticosteroids were tapered off. The child has been in sustained remission for over a year with mycophenolate mofetil monotherapy.

Isolated sarcoid granulomatous interstitial nephritis responding to infliximab therapy

Sarcoidosis is a systemic disease with multiorgan involvement. In children, renal impairment of sarcoidosis usually is caused by either hypercalcemia leading to nephrocalcinosis or interstitial nephritis with or without granulomata. We report the case of a 13-year-old boy presenting with severe arterial hypertension and acute renal failure caused by an isolated sarcoid granulomatous interstitial nephritis (GIN). Other known causes of GIN, eg, drug intake or fungal or mycobacterial infection, were excluded, and there was no evidence of extrarenal sarcoid involvement. Renal function improved initially with prednisone treatment. Blood pressure was controlled using ramipril, nifedipine, furosemide, dihydralazine, and metoprolol. Later, the patient showed signs of severe steroid toxicity and progressive renal failure. Monthly treatment with infliximab, a tumor necrosis factor-alpha antibody, was started, resulting in steady improvement in renal function and resolution of renal granulomata. In addition, antihypertensive medication could be reduced, and low-dose prednisone therapy was maintained. To our knowledge, this is the first report of successful treatment with infliximab of a patient with sarcoid GIN.

Cutaneous nephrology

There are numerous cutaneous findings that may be related to coexistent renal disease. An astute clinician may use careful skin examination to make early diagnosis of renal conditions in some cases, and institute appropriate therapy as soon as indicated.