Primary synovial epithelioid sarcoma of the knee: distinctly unusual location leading to its confusion with pigmented villonodular synovitis

Epithelioid sarcoma (ES) is a rare malignant soft tissue tumor occurring in the distal extremities of young adults and is characterized histologically by nodules of epithelioid cells showing central necrosis. Intra‐articular ES is extremely rare; only four cases have been reported, but their radiologic and histologic documentation of intra‐articular origin have been imprecise. We report the first radiologically and histologically well‐documented case of primary synovial ES. A 59‐year‐old woman presented with pain followed by swelling of her right knee for 6 months. MRI revealed an entirely intra‐articular nodular synovial mass in the lateral part of the right knee joint in a background of diffusely thickened synovium. Synovectomy was performed under the clinical impression of pigmented villonodular synovitis (PVNS), a diagnosis erroneously confirmed by the reporting pathologist. The tumor rapidly recurred 3 months afterward and the diagnosis of primary synovial ES was made. Despite above‐knee amputation, the tumor continued to spread proximally to the retroperitoneum. She developed multiple lung metastases and died 20 months after initial presentation. The nodular aggregates of tumor cells with central necrosis resulted in diffuse polypoid synovial thickening mimicking tuberculous synovitis and PVNS. The tumor cells showed positive staining for EMA, CK19, CD34, and complete loss of INI1 staining, establishing the diagnosis of primary synovial ES. The ES spread from the synovium to and along the joint capsule, and then extra‐articularly into the soft tissue surrounding the knee joint, with lymphovascular permeation. Such pattern of spread calls for radical surgical excision as the treatment of choice.     

Low rate of return to pre-injury level of sports after multi-ligament knee injury – Functional outcomes after MLKI

BackgroundMulti-ligament knee injury (MLKI) is a rare but severe injury with potential devastating complications. The primary goal of this study was to investigate return to sports and work after MLKI. Secondary outcomes were patient reported outcome measures (PROMs), treatment, time between trauma, diagnosis and treatment, and neurovascular damage.MethodA database search was performed to identify all patients with MLKI in our hospital (2010–2017). Pre-defined variables were collected from patient files and questionnaires. Multiple regression analysis was used to study the relationship between different variables and PROMs.Results31 patients were included. The overall return to sports rate after a MLKI was 88.5%, but only 23.1% returned to their pre-injury level. 83.3% of the patients were able to return to work. Multiple regression analyses led to a significant prediction model for pain during rest (F(7,16) = 2.808, p = 0.041, R² = 0.355). Within this model, a higher age was a significant predictor for higher pain scores (p = 0.002). Age was also a significant (negative) predictor within the non-significant models for IKDC (p = 0.004) and Lysholm (p = 0.024). A delay between trauma and diagnosis of more than three months was seen in 32.3% of the patients.ConclusionsThis study showed a relatively high overall return to sports and work after MLKI, but less than a quarter returned to their pre-injury level of sports. An important finding was the substantial number of patients with a delay between trauma and diagnosis.This study contributes to more awareness and knowledge about MLKI among physicians, which is essential to reduce these delays.     

Immunoglobulin G4-related disease: case report and literature review

Immunoglobulin (Ig) G4-related disease (IgG4-RD) is a rare and chronic progressive clinical entity, characterized by elevated serum IgG4 along with tissue infiltration by IgG4 + plasma cells. It is an immune-mediated fibro-inflammatory condition that can affect virtually any organ and tissue. IgG4-related lung disease (IgG4-RLD) occupies 14% of all IgG4-RD, with nonspecific symptoms and various abnormal radiographic patterns. Published data on IgG4-related hypertrophic pachymeningitis (IgG4-RHP), an increasingly recognized central nervous system manifestation of IgG4-RD, is also limited. Both lung and cranial dura involvement have not yet been reported until now. We further entail a review of the literature on the clinicopathologic features and differential diagnosis of this uncommon disease. We herein report an interesting case of a 70-year-old male patient admitted due to headache and fever. A magnetic resonance imaging (MRI) of the brain revealed extensive dural thickening with marked enhancement. Chest computed tomography (CT) scan showed nodular or mass-like consolidation and focal interstitial change. Thoracoscopic lung biopsy and lumbar puncture were conducted. After careful histopathological observation and consideration of alternative differential diagnoses, he was diagnosed with IgG4-related disease with lung and cranial dural involvement based upon significant elevation of serum and cerebrospinal fluid (CSF) IgG4 concentration. The patient was started on oral prednisolone 60 mg/day (1.0 mg/kg/day) for 14 days, and a tapering dose of 5 mg every 2 weeks followed by maintenance therapy at low dose for 3 months. His clinical manifestations, and serologic and imaging findings improved with steroid treatment. Currently, the patient remains well without disease progression. IgG4-RD should be considered as a differential when diagnosing other similar multisystemic lesions. Clinical examination, careful histological observation, and immunostaining for appropriate markers are essential in establishing the diagnosis. Clinicians should become familiar with this alternative differential diagnosis.

     

Invasive rhino-orbital-cerebral aspergillosis in an immunocompetent patient

IntroductionRhino-orbital-aspergillosis (ROA) is a rare but serious disease in immunocompetent patients. Diagnosis is often delayed due to the absence of specific clinical symptoms. We describe the case of a patient who presented initially with ROA which spread progressively to the right ethmoid-sphenoid sinuses and then to the brain.ObservationA 61-year-old patient with a history of well-controlled diabetes presented with a sudden severe decrease in right visual acuity. Cerebral MRI showed the presence of an infiltrate in the right orbital apex extending to the homolateral cavernous sinus without any cerebral involvement. A diagnosis of right orbital myositis was made and corticosteroid therapy was started. His symptoms worsened progressively leading to quasi-blindness. A new MRI showed the development of right sphenoid-ethmoid osteolytic lesions. A fungal aetiology was suspected and tests for fungal biomarkers found a β-(1-3)-D-glucan level of 99 pg/ml but negative galactomannan. An ethmoid biopsy was performed for histological and mycological investigations, including the detection of Aspergillus DNA by qPCR. qPCR was positive and culture resulted in the isolation of multi-sensitive Aspergillus fumigatus. Treatment was initiated with voriconazole. Due to persistence of blindness and the appearance of a lesion extending to the right frontal lobe, surgical excision was performed followed by antifungal treatment for a total duration of 1 year. The patient is currently stable, but has persistence of blindness in the right eye.ConclusionInvasive ROA is a rare but serious disease in immunocompetent patients which should be evoked in the differential diagnosis of a tumour or vasculitis. Early diagnosis is essential for optimal management.     

Extranodal interdigitating dendritic cell sarcoma presenting in the pleura: a case report

Interdigitating dendritic cell sarcoma (IDCS) is an extremely rare neoplasm arising from the antigen-presenting cells of the immune system. This disease usually involves the lymph nodes, and rarely, extranodal sites may be affected. The authors report a case of extranodal IDCS presenting in the pleura. A 32-yr-old man presented with progressive chest pain. Imaging studies showed diffuse pleural thickening with pleural effusion. Morphological and immunohistochemical analysis of an incisional biopsy of the pleura were consistent with a diagnosis of IDCS; tumor cells were positive for S100 and CD45, but negative for CD1a, CD21, CD35, B cell and T cell markers. The patient was administered chemotherapy, but died of progressive disease. Although its incidence is extremely rare, this case suggests that extranodal IDCS should be considered in the differential diagnosis of undifferentiated neoplasms and that immunohistochemical staining be performed using appropriate markers.     

A chinese boy with geleophysic dysplasia caused by compound heterozygous mutations in ADAMTSL2

Geleophysic dysplasia, belonging to the group of acromelic dysplasia, is a rare genetic disease. Two genes, FBN1 and ADAMTSL2, were known to be linked to this disorder. The disorder presents as extreme short stature, short limbs, small hands and feet, stubby fingers and toes, joint stiffness, toe walking, skin thickening, progressive cardiac valvular thickening and characteristic facial features, including a round face with full cheeks. Here, we report the first Chinese case with geleophysic dysplasia type 1 based on clinical and genetic features. The boy was admitted because of severe physical growth retardation and mild motor retardation. Comprehensive medical evaluations were performed including metabolic studies, endocrine function examination, bone X-rays and echocardiography. Much delayed bone age and geleophysic dysplasia were found. Targeted next-generation sequencing was used to detect genetic mutations associated with skeletal dysplasia. Sanger sequencing was used to confirm the mutations in the patient. PCR amplification, cloing, and sequencing was used to determine the de novo mutation origin. Two compound heterozygous mutations were confirmed in the ADAMTSL2 gene of the patient. The c.340G > A (p.Glu114Lys) mutation was a de novo heterozygous mutation, and our results suggested that it was located on the paternal allele. While the c.234-2A > G inherited from his mother was a novel pathogenic heterozygous splicing mutation. Growth hormone deficiency had been observed in the patient. His growth velocity was improved by growth hormone supplementation. In conclusion, we have identified a novel splicing mutation of ADAMTSL2 carried by a Chinese boy with geleophysic dysplasia type 1. The patient was treated effectively with growth hormone supplementation.     

Cerebral phaeohyphomycosis due to Cladophialophora bantiana in a French Guianese child

We report a case of cerebral phaeohyphomycosis, a fungal brain infection due to a dark (dematiaceous) fungi in a 6-year-old French Guyanese boy. The child presented fever and drowsiness due to several paraventricular brain abscesses. Neurological surgeries were performed to reduce intracranial hypertension and to obtain abscess biopsies. Mycological cultures of intraoperative samples led to the diagnosis of cerebral phaeohyphomycosis due to Cladophialophora bantiana. The patient neurological status deteriorated and remained critical after several weeks of combination antifungal therapy with voriconazole 8 mg/kg/day, liposomal amphotericin B 10 mg/kg/day and flucytosine 200 mg/kg/day. A complete surgical resection was not possible because of multiple small abscesses. A multidisciplinary ethical staff decided on home medical care with palliative ventriculoperitoneal shunt, nasogastric feeding and analgesics. One year later, the patient's neurological condition had improved and cerebral lesions had regressed, while he had not received any antifungal treatment but only traditional medicines. Cerebral phaeohyphomycosis are rare diseases affecting immunocompromised but also apparently non-immunocompromised patients, as in this case. A complete surgical resection is not always possible and mortality rates are high in spite of treatments with a combination of antifungals. The diagnosis may be difficult because of these dematiaceous fungi's slowly growing and their potential pathogenicity for laboratory staff.     

Pulmonary tumor thrombotic microangiopathy

Pulmonary tumor thrombotic microangiopathy (PTTM) is characterized by widespread fibrocellular intimal proliferation of the small pulmonary arteries and arterioles in patients with metastatic Carcinoma. Microscopic pulmonary tumor emboll have frequently occurred in patients with malignant tumors; however, few cases of PTTM have been reported. A rare case of a patient with gastric adenocarcinoma who presented with acute dyspnea and lethal respiratory failure is described. Histologically, diffuse fibromuscular intimal thickening cauring luminal stenosis and obstruction but containing rather few cancer cells was observed in the small pulmonary arteries and arterioles. These findings were consistent with PTTM. Atthough PTTM is a rare phenomenon, PTTM should be considered in the differential diagnosis of acute dyspnea or pulmonary hypertension in patients with carcinoma.     

Familial occurrence of warts, hypogammaglobulinemia, infections, and myelokathexis (WHIM) syndrome

Introduction:  Warts, hypogammaglobulinemia, infections, and myelokathexis (WHIM) syndrome is a rare immunodeficiency disorder with an autosomal-dominant pattern of inheritance and low fatality rate but significant lifelong morbidity. Materials and Methods:  A 27-year-old mother of two children has been suffering from severe neutropenia and recurrent infections with the diagnosis of sporadic WHIM syndrome established by sequencing the CXCR4 gene and the finding of a heterozygous 1000 C→T nonsense mutation in the second CXCR4 exon. The first child was an apparently healthy boy delivered at full term. Umbilical cord blood cells were obtained for genetic analysis. Peripheral blood cells were also analyzed at 8 months of life. Both analyses revealed the same mutation as that of his mother. The child was in a good condition, manifesting neutropenia without infections until 11 months of life. He subsequently developed pneumonia requiring a more aggressive treatment. After that, the regular substitution of immunoglobulins (IVIGs) and G-CSF has been preventing serious infections. Six months ago the second boy was delivered who also demonstrated neutropenia without severe infections. Genetic studies using cord blood and also peripheral blood cells in the fourth month showed an identical mutation of the CXCR4 gene as in his mother. Moreover, the mother and her first son demonstrated monocytopenia. Results:  The results indicate that genetic defects connected with WHIM syndrome may influence not only the granulocyte, but also the monocytic lineage. Moreover, a perinatal diagnosis of WHIM syndrome made by sequencing the CXCR4 gene should be performed in cases where either parent is known to be affected with this disease. Conclusions:  This would facilitate an earlier detection of the deficiency in children, thereby allowing a more comprehensive follow-up and administration of appropriate therapy.     

Malignant mesothelioma with osteoblastic heterologous elements

A 59 year-old man with a history of asbestos exposure presented with a right pleural effusion and a diffuse pleural thickening with focal calcifications on chest X-ray. Cytological examination of pleural fluid indicated malignant mesothelioma. A biopsy specimen showed malignant mesothelioma surrounding a fragment of mature bone. The patient was treated with intrapleural interferon, but relapsed 3 years later. A fresh biopsy specimen showed round tumor cells surrounding osteoid substance. Only ten cases of this rare variant of malignant mesothelioma with osteoblastic heterologous elements have been reported in the literature. The most difficult differential diagnosis is primary pleural osteosarcoma.     

A case of pulmonary alveolar microlithiasis

Pulmonary alveolar microlithiasis (PAM) is a rare disease with unknown etiology and pathogenesis. It is characterized by diffuse, innumerable, and minute calculi, called microlithiasis in the alveoli. More than half of reported cases are asymptomatic at the time of diagnosis. We describe the first case of PAM in Korea. A 19-yr-old man without respiratory symptoms presented with interstitial thickening on the chest radiograph. His chest high resolution CT scan showed diffusely scattered, ill defined tiny micronodules and interstitial thickening. Open lung biopsy confirmed the diagnosis of PAM. He was followed up for 6 months without treatment, and no progression was noticed.     

From the archives of MD Anderson Cancer Center: Untreated leukemic non-nodal mantle cell lymphoma with relapse as pleomorphic variant mantle cell lymphoma 21 years later

Leukemic, non-nodal mantle cell lymphoma (MCL) is a distinct, rare, indolent variant of mantle cell lymphoma, but can relapse aggressively. It can present with lymphocytosis with chronic lymphocytic leukemia (CLL)-like morphologic and immunophenotypic features as was initially considered in the index case. However, at time of splenectomy, two years later cyclin D1 overexpression was shown and the disease was realized to be leukemic non-nodal MCL. The patient was followed for 21 years, without therapy, before he developed clinically aggressive MCL with lymphadenopathy. Lymph node biopsy showed MCL, pleomorphic variant. We review the literature and discuss the features of leukemic non-nodal MCL as well as the potential pitfalls in diagnosis. Furthermore, we are not aware of another cases reported with a 21 year interval from initial diagnosis of leukemic non-nodal MCL to aggressive MCL.     

Clinical features of actinomycosis: A 20-year experience of a single institute in Southern China

BackgroundActinomycosis is a rare indolent infectious disease with nonspecific clinical presentations that delay diagnosis. Although actinomycosis is thought to be more prevalent in developing countries, data from developing countries are scarce. This study aimed to profile actinomycosis in developing countries and identify how it differed from profiles of developed countries.MethodsPatients fulfilling the inclusion criteria for actinomycosis from Nanfang Hospital in southern China between January 1999 and December 2018 were retrospectively analyzed. We described clinical characteristics, diagnostic procedures, differential diagnosis, and management of actinomycosis of clinical significance.ResultsThirty‑one patients were included in this study. The disease was diagnosed predominately in the orocervicofacial (n = 14), cardiothoracic (n = 11), abdominopelvic (n = 5), and soft tissue (n = 1) regions. Diagnosis was obtained by either histopathology (n = 29, 94%) or microbiology (n = 2, 6%). Only one-third of patients presented with general symptoms, such as fever and weight loss. Ten were lost during follow-up, and the median duration of antibiotic use was 93.5 days (interquartile range 28–300), whereas the median follow-up time was 34 months (interquartile range 9–132). Ten patients receiving complete resection of the lesion were cured without postoperative use of antibiotics. Only one patient relapsed during the follow-up period.ConclusionsActinomycosis is a rare disease even in developing countries, and both misdiagnosis and missed diagnosis are common. Diagnosis was often delayed and was obtained postoperatively from histopathology in developing countries. Hence, clinicians should be aware of this disease in patients with high risk factors. In the future, specific molecular methods may help to improve early diagnosis and treatment.     

Pure post-pubertal yolk sac tumor of the testis: An extremely rare and aggressive entity

ContextPure post-pubertal yolk sac tumors (YSTs) are an extremely rare type of malignant germ cell tumor (GCT) that account for <1 % of testicular GCTs. Clinically, they are more aggressive compared to the more common pre-pubertal counterpart. The aim of this study is to analyze the clinical presentation, ancillary tests and clinical outcomes in addition to presenting a spectrum of histomorphological features, in a case series along with a literature review.DesignA retrospective review of 4 cases of pure post-pubertal YST of the testis was performed.Data collected for each patient included demographics, clinical presentation, serum markers, radiology and pathologic findings, treatment, and clinical outcomes.ResultsAll patients presented with a testicular mass with or without associated pain and elevated serum alpha-feto protein. Mean age at presentation was 36 years (range 25–68 years). Two patients presented with metastatic disease at the time of diagnosis. Histologic patterns and features are as follows: germ cell neoplasia in-situ (n = 4), reticular/microcystic, solid, glandular, papillary, endometrioid, cystic, necrosis and angiolymphatic invasion (n = 3). Fluorescent in-situ hybridization test performed on Case 2, showed presence of isochromosome 12p and next generation sequencing showed gains of 12p. Case 1, 2 and 4 showed metastatic disease on follow-up.ConclusionsDiagnosis of pure post-pubertal YST remains challenging due to the variety of morphologic patterns often present in these tumors. Extensive sampling along with use of ancillary tests is the key for diagnosis. In this study, 75 % of cases had metastatic disease at or after the diagnosis confirming the aggressive nature of this rare entity.     

Familial epilepsy with anterior polymicrogyria as a presentation of COL18A1 mutations

Knobloch syndrome [OMIM: (KNO1) #267750] is a rare and clinically heterogeneous autosomal recessive disorder caused by mutations in COL18A1. Knobloch syndrome is characterised by abnormalities of the eye and occipital skull defects however the full phenotypic spectrum is yet to be defined. This report describes a family of four affected sisters with polymicrogyria, refractory seizures, and intellectual impairment of varying severity with a Lennox-Gastaut phenotype, and complex eye abnormalities where a syndromic diagnosis was not initially made. Whole exome sequencing of two affected sisters followed by filtering for rare and potentially disease causing variants in all genes identified compound heterozygous variants in NM_030582.3 (COL18A1): c.3690G > A: p.(Trp1230*) and NM_030582.3 (COL18A1): c.4063_4064delCT: p.(Leu1355Valfs*72). The two variants co-segregated with the affected individuals in the family. Identification of COL18A1 mutations in individuals with a Lennox-Gastaut phenotype and anterior polymicrogyria but lacking the classical occipital encephalocele expands the COL18A1 clinical spectrum.     

Homogénéité mutationnelle de la glycogénose de type Ia en Tunisie

The glycogen storage disease type Ia (GSD Ia) is a rare inherited disorder, with autosomal recessive determinism. It is characterized by hepatomegaly, short stature and hypoglycemia with lactic acidemia. The confirmation of diagnosis is based on the enzymatic assay performed on liver biopsy. For Tunisians patients, this biochemical test is performed abroad. The aim of our study is the molecular characterization of GSD Ia in Tunisian patients and the development of a molecular diagnosis tool. Our study included 27 patients from 23 unrelated families, mutation analysis revealed that the R83C mutation is the most frequent (65%, 30/46 mutant alleles), followed by the R170Q mutation (30%, 14/46 mutant alleles). The homogeneity of mutation spectrum of GSD Ia in Tunisia allows the development of a cost effective and reliable tool for the confirmation of clinical diagnosis among suspected GSD Ia patients.     

Primary endocardial fibroelastosis: an underappreciated cause of cardiomyopathy in children

BackgroundEndocardial fibroelastosis (EFE) is a thickening of the endocardium by collagen and elastic fibers. Primary EFE is characterized by a dilated left ventricle (LV) that typically has a high takeoff of the papillary muscles and thickening of the free edge of the mitral valve leaflets, in addition to diffuse thickening of the endocardium by aortic-like thick and parallel elastic fibers. In the past, EFE was considered a rare cardiomyopathy, but in the latest American Heart Association classification (2006) of cardiomyopathies, EFE is not mentioned. The existence of the entity of “primary” EFE has been questioned.MethodsWe reviewed medical records, echocardiograms, explanted hearts, and microscopic slides from 52 pediatric heart transplant cases at our institution with a diagnosis of dilated cardiomyopathy (DCM).ResultsFourteen hearts showed both gross and microscopic findings of primary EFE, with no apparent cause of the diffuse endocardial thickening. Patients with EFE were significantly younger than patients with DCM (median age: 10.1 vs. 142.0 months). No case of EFE was diagnosed clinically. LV wall and endocardial thickness were significantly greater in EFE, with the mitral valve and papillary muscles showing characteristic findings.ConclusionsClinically and pathologically, EFE is different from DCM. EFE is not rare and found in 25% of pediatric cases transplanted for “DCM.” EFE should be recognized to promote understanding of the natural history and etiology of EFE.     

Primary Ewing sarcoma of the lung: A systematic review of the recent literature

Primary pulmonary Ewing sarcoma (PES) is a rare malignancy with only sporadic cases reported in the scientific literature. We performed a systematic review of the cases published in the last decade on PubMed, with the aim to describe the clinical, pathological, therapeutic, and prognostic data of PES. Forty-two articles reporting on 50 cases have been reviewed. Globally, 60 % of the patients were males, and the mean age at diagnosis was 30.5 years, with only a few cases diagnosed after 50 years of age. The most common clinical manifestations at diagnosis were dyspnea, cough and chest pain. The most common immunohistochemistry findings were staining for CD99 and (less frequently) for vimentin, and no staining for TTF-1, cytokeratin, desmin and S-100. ESWR1-FL1 translocation was tested in less than half of the cases. The disease was often locally advanced, treated generally with multidisciplinary treatment combining surgery, chemotherapy and radiation therapy. Among patients with follow-up data, approximately 40 % were dead at the time of publication, with the median survival being 11.5 months. Among those who were alive, only 8.3 % was free from disease at 48 months from diagnosis.     

Juvenile and adult xanthogranuloma: A 30-year single-center experience and review of the disorder and its relationship to other histiocytoses

BackgroundJuvenile xanthogranuloma (JXG) is the most common type of non-Langerhans cell histiocytosis whose cell of origin, etiology and pathogenesis are not fully understood. We aimed to provide an update on histopathologic and immunophenotypic profile of this well-characterized entity whose relationship to the other histiocytoses has received renewed attention in light of recent molecular genetic studies.Materials and methodsA retrospective review of all the cases with the pathologic diagnosis of “xanthogranuloma” was performed on our archives from 1989 to 2019.ResultsA total of 525 patients with 547 lesions diagnosed as JXG were identified with the median age of 4.5 years, a male predominance (M:F ratio 1.3:1) and a predilection for the head and neck region (40.8%). Cutaneous lesions comprised 76.8% cases and another 15.7% presented within soft tissues. The most common non-soft tissue, extracutaneous lesions included the brain (2.6%), and lungs (1.8%). Three basic histopathologic patterns were identified: early classic (EJXG) (14.2%), classic (CJXG) (45.3%), and transitional JXG (TJXG) (40.5%). Multinucleated giant cells, either Touton or non-Touton, were most frequently present in CJXG followed by TJXG. Mitosis was rare (<1/10 high-power field) among different patterns. There was an association among the patterns and lymphocytic infiltrates (P = 0.036), and presence of Touton or non-Touton giant cells (P < 0.001 for both) but not for mitotic count (P = 0.105) or eosinophilic infiltrates (P = 0.465). Additionally, there was a correlation between age groups and presence of non-Touton giant cells (P = 0.012) but not for Touton cells (P = 0.127). We have demonstrated that immunophenotypic expression of the lesion was not associated with age at diagnosis nor morphologic pattern: factor XIIIa 192/204 (94.1%), CD11c 75/77 (97.4%), CD4 82/84 (97.6%), CD68 200/201 (99.5%), CD163 15/15 (100%), CD1a 1/110 (0.9%), S-100 48/152 (31.6%), CD31 15/21 (71.4%), and vimentin 104/105 (99.0%).ConclusionWe have documented in a substantial series of cases of JXG that there is a correlation between one of the three basic histopathologic patterns with age at diagnosis, but with a consistent immunophenotype among the three patterns. Considering sensitivity and specificity rates, we suggest that a combination of CD11c, CD4, CD1a and either CD163 (preferred) or CD68 stains provides more specific diagnostic yield in the differentiation of JXG from other histiocytic disorders. JXG is also discussed in terms of its relationship and distinction from other similar histiocytic disorders in the context of MAPK/ERK pathway mutations.     

Peritubular capillary basement membrane changes in chronic renal allograft rejection: Comparison of light microscopic and ultrastructural observations

Marked peritubular capillary basement membrane (PTCBM) multilayering, the ultrastructural feature of chronic antibody-mediated rejection (ABMR) of kidney allografts, was found to correspond histologically to PTCs with thickened BMs; such PTCs have been suggested as a novel histological marker of chronic rejection. We investigated whether scoring of PTCBM thickening can substitute the ultrastructural search for PTCBM multilayering. The thickening was graded in PAS- and Jones-stained sections in 110 biopsies from recipients with a late dysfunction, all examined ultrastructurally for transplant capillaropathy (≥3 PTCs with ≥5 BM layers). Grade 0 indicated no thickening. Grade 1 and grade 2 were assigned when the PTCBMs were as thick as or thicker than those of the non-atrophic tubules, and duplication/chain-like lamination of the PTCBM was noted in ≤3 or ≥4 high-power fields, respectively. The series was enrolled in subgroups of those with and those without histopathological lesions of chronic rejection. Fifty-six biopsies displayed lesions of chronic ABMR. Transplant capillaropathy was demonstrated in 40 biopsies. Grade 2 thickening furnished a substantial interobserver concordance rate (κ = 0.803) and correlated with the transplant capillaropathy. Jones staining performed somewhat better in scoring than PAS staining. Grade 2 thickening was verified in 35 biopsies involving chronic ABMR, and in one control biopsy (sensitivity 61.4%, specificity 0.98). Grade 1 thickening was not suggestive of chronic ABMR at all. In conclusion, grade 2 thickening can be regarded as the histopathological lesion of chronic ABMR; however, electron microscopy remains the gold standard in the assessment of PTCBM changes.