Spectrum of podocytopathies in new-onset nephrotic syndrome following COVID-19 disease: a report of 2 cases.

BACKGROUND: Coronavirus disease-2019 (COVID-19) is an ongoing pandemic which has affected over 12 million people across the globe. Manifestations in different organs systems are being reported regularly. Renal biopsy findings in hospitalized COVID-19 patients presenting solely with acute kidney injury (AKI) have recently been described in published literature in few case reports. The findings include diffuse acute tubular injury (ATI) along with the glomerular lesion of collapsing glomerulopathy (CG). However, nephrotic syndrome as the presenting complaint of COVID-19 has not been reported widely, neither has any other glomerular lesion other than CG. CASE PRESENTATION: We describe the kidney biopsy findings of two patients who had recent diagnoses of COVID-19 and presented with new-onset nephrotic syndrome. Renal biopsy in both patients showed ATI (as in previous reports) and distinct glomerular findings on light microscopy - that of minimal change disease (MCD) initially in one patient followed by CG in a subsequent biopsy and CG at the outset in the other patient. The electron microscopic findings in both patients were that of severe podocytopathy (diffuse and severe podocyte foot process effacement). CONCLUSION: Our cases highlight a novel clinical presentation of COVID-19 renal disease, not described before, that of new-onset nephrotic syndrome. While all published case reports describe CG as the glomerular pathology, we describe a non-CG pathology (MCD) in one of our cases, thereby adding to the repertoire of renal pathology described in association with COVID-19 patients. However, the exact mechanism by which podocyte injury or podocytopathy occurs in all such cases is still unknown. Optimal treatment options for these patients also remains unknown at this time.

Crystalglobulin-associated nephropathy presenting as MGRS in a case of monoclonal B-cell lymphocytosis: a case report.

BACKGROUND: Crystalglobulin-associated nephropathy (CAN), a rare subtype of monoclonal gammopathy, usually associated with multiple myeloma and occasionally monoclonal gammopathy of uncertain significance (MGUS), is characterized by occluding monoclonal pseudothrombi within renal glomerular capillaries and/or interstitial arterioles. Ultrastructurally, these pseudothrombi are unique for having a crystalline substructure. We describe a case of an adult patient with monoclonal B-cell lymphocytosis (MBL) and acute renal failure whose kidney biopsy revealed a rare diagnosis of CAN. CASE PRESENTATION: A 63-year old male presented with a 2-month history of edema, arthralgia and malaise. He had acute kidney injury with hematoproteinuria on urine analysis. Serum and urine protein electrophoresis were both negative. A renal biopsy however revealed features of CAN. Organomegaly, bone pain and lymphadenopathy were absent. A repeat serum electrophoresis was positive for IgA kappa and a free light chain assay showed elevated free kappa light chains. Flow cytometry done subsequently revealed a diagnosis of MBL, chronic lymphocytic leukemia (CLL) type. CONCLUSION: CAN in association with MBL/CLL has not been previously described in literature, and our case highlights yet another instance of monoclonal gammopathy of renal significance (MGRS) where a small B-cell clone resulted in extensive renal pathology without systemic manifestations.

Renal crystal-storing histiocytosis involving glomeruli - A comprehensive clinicopathologic analysis.

Crystal-storing histiocytosis (CSH) is a rare manifestation of monoclonal gammopathy in which histiocytes containing monoclonal proteins in their cytoplasm are found in various organs of the body including the kidney. Within the kidney, these monoclonal crystal-laden histiocytes have been described to occur in the interstitium (most commonly) or in the glomerular mesangium. CSH within glomerular capillary loops has rarely been reported. We describe three cases of CSH primarily affecting the glomerular capillaries and review the literature of CSH in general. Twenty cases of CSH involving the kidney are present in the literature; three describe CSH in glomeruli, only one of which showed histiocytes predominantly in glomerular capillary loops, while 15 had predominantly or solely interstitial CSH. Most cases involve IgG kappa crystals with only one case involving lambda light chain. Patients with CSH predominantly involving the glomerular capillaries showed a trend toward lower serum creatinine and proteinuria at presentation, and several patients with CSH lacked a definitive diagnosis of a monoclonal gammopathy at the time of diagnosis, emphasizing the role that kidney biopsy and particularly electron microscopy play in diagnosis of this entity.

A rare case of lamotrigine-induced acute interstitial nephritis.

Medications, especially non-steroidal anti-inflammatory drugs and antimicrobials, have been most commonly associated with acute interstitial nephritis (AIN); antiepileptic drugs (AEDs) are rarely known to cause AIN. This is a case of a 27-year-old male who was recently started on treatment with lamotrigine for bipolar disorder and was found to have rapidly progressive renal failure. Renal biopsy features were suggestive of AIN. Lamotrigine-induced AIN was suspected to be the most likely cause. Discontinuation of the drug and treatment with steroids resulted in complete renal recovery. Lamotrigine use has been recently gaining popularity, not only as an AED but also as a mood stabilizer. With the use of this drug becoming more popular, it is important to emphasize that - although rare - AIN is one of its potential complications.

Follicular pancreatitis: a distinct form of chronic pancreatitis-an additional mimic of pancreatic neoplasms.

Follicular pancreatitis is a recently described variant of chronic pancreatitis characterized clinically by the formation of a discrete pancreatic mass and histologically by the presence of florid lymphoid aggregates with reactive germinal centers. Our aim was to study the clinical and histologic features of follicular pancreatitis, as well as to critically examine potential overlap with autoimmune pancreatitis. Immunohistochemistry for Bcl-2, CD21, κ and λ light chains as well as IgG4 and IgG were performed. We found a total of 6 patients (male-female ratio, 2:1; mean age, 57 years) who fulfilled the diagnosis of follicular pancreatitis in our institutions. Four had an incidental diagnosis, while two presented with abdominal pain, fatigue, and elevated liver enzymes. On imaging, 3 patients had a discrete solid mass, whereas 2 cases showed a dilated main pancreatic duct, mimicking an intraductal pancreatic mucinous neoplasm on imaging. One patient had a lesion in the intra-pancreatic portion of the common bile duct. On histopathology, all cases showed numerous lymphoid follicles with Bcl-2-negative germinal centers either in a periductal or in a more diffuse (periductal and intra-parenchymal) fashion, but without attendant storiform fibrosis, obliterative phlebitis, or granulocytic epithelial lesions. IgG4-to-IgG ratio was <40% in 5 cases. A comparison cohort revealed germinal centers in 25% of type 1 autoimmune pancreatitis and 2% of type 2 autoimmune pancreatitis cases, but none were periductal in location. In conclusion, follicular pancreatitis, an under-recognized mimic of pancreatic neoplasms is characterized by intrapancreatic lymphoid follicles with reactive germinal centers.

Hyalinizing cholecystitis with features of immunoglobulin G4-related disease-coincidence or an unrecognized association? A case report.

Hyalinizing cholecystitis (HC) is a recently described rare subtype of chronic cholecystitis characterized by dense, paucicellular collagenous transmural fibrosis, which usually replaces the mucosa and muscularis propria. Immunoglobulin (Ig)G4-associated cholecystitis is also a newly described cholecystitis variant characterized by transmural or extramural lymphoplasmacytic inflammation, lymphoid follicles, storiform fibrosis, phlebitis, and increased tissue IgG4-positive plasma cells. We describe a case of cholecystitis in an elderly white man who harbored features of both HC and IgG4-associated cholecystitis. In retrospect, the patient also had a significantly elevated serum IgG4 level. To the best of our knowledge, an association between HC and IgG4-related disease has not been previously described in the literature. Although not entirely conclusive, our observations raise the possibility that some cases of HC represent the end stage of IgG4-related disease.

Histologic findings in skin biopsy in a JMML rash: a case report and review of literature.

Juvenile myelomonocytic leukemia (JMML), belonging to the category of myeloproliferative/myelodysplastic syndromes, is a rare pediatric hematologic malignancy with frequent skin manifestations commonly in the form of rashes. However, these rashes are not always biopsied and their immunophenotype studied in details. We report one such case in a 2-year-old boy who presented with a 1-month history of nonresolving fever, fatigue, and pallor along with a generalized maculopapular skin rash. The child also had mild hepatomegaly. A complete blood count with differential revealed a hemoglobin value of 8.6 g/L, leukocytosis (white blood cell count of 55.3 × 109/L), absolute monocytosis (27 × 109/L), immature granulocytes, and a platelet count of 126 × 109/L. The bone marrow aspirate showed a hypercellular marrow with trilineage hematopoiesis, 10% blasts (including promonocytes), increased monocytes (46%), and dysplastic changes in the erythroid and myeloid cell lines. These findings along with absence of a BCR-ABL1 fusion gene and a hemoglobin F level of 3.4% were consistent with the diagnosis of JMML, which was confirmed by subsequent positive granulocyte macrophage-colony stimulating factor hypersensitivity and NRAS mutation studies. A skin biopsy of the rash revealed a dermal infiltrate composed predominantly of atypical monocytic cells that were positive for CD68, myeloperoxidase, and lysozyme and negative for CD117, CD1a, and S100, consistent with JMML.

Nitric oxide synthase 3 and endothelin 1 immunoreactivity in pulmonary hypertension.

CONTEXT: Pulmonary hypertension (PH) is a serious and sometimes life-threatening event that occurs as a complication of various cardiopulmonary disorders, of which rheumatic heart disease (RHD) is an important example in our country. The pathogenesis of PH is a complex, multistep process in which "pulmonary endothelial dysfunction" (PED) is widely regarded as the central pathogenetic event. PED is, in turn, influenced by several local and systemic factors, of which nitric oxide synthase 3 (NOS3) and endothelin 1 (ET1) are 2 prime candidates, and are the subject of our study. AIMS: Our aim was to study the immunoreactivity of NOS3 and ET1 in the pulmonary vasculature of PH patients of various etiologies, with emphasis on RHD cases. SETTINGS AND DESIGN: A retrospective, autopsy-based study. SUBJECTS AND METHODS: A total of 49 autopsy cases (39 patients and 10 controls) were chosen for our study. Of the 39 patients, 20 had PH secondary to RHD, whereas the remaining 19 patients had non-RHD etiologies as the basis of their PH. Lung sections taken from all the 49 cases were subjected to routine H and E, elastic van Gieson, and immunohistochemical staining (with NOS3 and ET1 separately). The intensity of immunostaining in all the cases and controls were then graded as focal/diffuse and weak/strong. RESULTS: Controls showed positivity for both NOS3 (bronchiolar epithelium) and ET1 (endothelium of pulmonary arteries). Characteristic changes of PH on H and E were seen in 14 out of 19 non-RHD cases, which matched with the number of ET1 positivity cases. Similarly, for the RHD cases, 14 out of 20 cases showed changes of PH on H and E, but only 2 cases showed mild, focal positivity for ET1. Surprisingly, NOS3 positivity was largely absent in both the non-RHD and RHD cases. CONCLUSIONS: Our study showed NOS3 negativity and ET1 positivity in the lung vasculature of patients with PH, a conclusion more or less in line with the predominant view of the other investigators in this field. But at the same time, our study could not conclude an unequivocal role of NOS3 in PH, whereas it could, in the case of ET1.

Giant adrenal myelolipoma.

Adrenal myelolipoma is a rare benign tumor composed of adipose and hematopoietic tissue. Most tumors are small in size and incidentally detected. We report a case of giant adrenal myelolipoma weighing 2200 gms which was diagnosed on radiology as a liposarcoma. This case is unusual in view of the large size and presence of bony spicules. To the best of our knowledge, not more than 10 giant adrenal myelolipoma cases have been reported in literature.