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Solitary fibrous tumor (SFT) is a rare tumor of mesenchymal origin that most commonly involves the pleura but can be found anywhere in the body. SFT can range from indolent benign tumors to aggressive malignant tumors, and pre-operative diagnosis is based mainly on imaging. In this case report, we describe an extremely rare case of SFT of left maxilla on F-18 FDG PET-CT and Ga-68 DOTANOC PET-CT. Very few cases of PET-CT findings in SFT are reported in literature; and to our knowledge, none involving the maxilla. By highlighting the findings on F-18 FDG and GA-68 DOTANOC PET-CT, we aim to further add on to the role of both the tracers in the diagnosis and management of this tumor group.

Background:Schwannomas are benign nerve sheath tumors that are extremely rare in the biliary tract. A comprehensive review of literature enumerated approximately 30 case reports of schwannoma in the biliary tract tree and porta hepatis region. Case Presentation:We report a case of a 40-year-old female who presented with abdominal pain. Imaging revealed a mass at the porta hepatis extending from the portal bifurcation till the hilum encasing the main portal vein and abutting the right portal vein. Differentials of carcinoma, lymphoma, and mesenchymal tumor were kept. Ultrasound-guided biopsy of the mass showed a benign nerve sheath tumor, immunopositive for S100. The histopathological evaluation of the excised mass confirmed the origin of mass in the common bile duct. Conclusions:Our case highlights that schwannomas, though benign, can mimic a carcinoma or lymphoma if present at a rare site such as bile ducts. An exhaustive clinical and radiological workup with diligent histopathological evaluation is mandatory in dealing with such rare cases as radical surgery and chemotherapy can be avoided in such patients.

Renal cell carcinoma (RCC) accounts for ~2% of global cancers and deaths. Survival depends on initial staging and shows poor survival rate in metastatic disease. CT and MRI are used for evaluating RCC, and PET/CT is used for metastatic disease assessment. We report a case of RCC, where both 18F-FDG and 68Ga-PSMA PET/CT showed increased uptake in liver metastatic lesions; however, a subhepatic peritoneal deposit showed uptake only in PSMA. Also, liver lesions were seen better in PSMA owing to lesser background uptake, suggesting a possibility of 68Ga-PSMA being a potential tracer for RCC evaluation.

Introduction:The term monoclonal gammopathy of renal significance (MGRS) has been described to include patients with renal manifestations associated with circulating monoclonal proteins with or without a clonal lymphoproliferation (B-cell or plasma cell) and not meeting diagnostic criteria for an overt hematological malignancy. A host of MGRS-associated lesions have been described that involve various renal compartments. Our study describes the histomorphological spectrum of MGRS cases at our center in the last 5 years and description as per the classification system of the International Kidney and Monoclonal Gammopathy Research Group (IKMG). Material and Methods:Retrospective analysis was carried out of all the renal biopsies with characteristic monoclonal immunoglobulin lesions for histopathological diagnosis between years 2015 and 2020 and reviewed by two independent pathologists. Results:Most patients in the study belonged to the fifth decade, with a median age of 50 years (mean 50.14 ± 10.43) range (24–68 years) with a male preponderance. Most patients presented with proteinuria as the sole manifestation (66.6%). Many of the patients (48%) had an M spike by serum protein electrophoresis or urinary protein electrophoresis with an abnormal serum free light chain assay (60.8%). AL amyloidosis was the most common diagnosis observed on histopathological evaluation (68.7%), followed by light chain deposition disease (10.4%). Conclusion:MGRS lesions are infrequently encountered in the practice of nephropathology and pose a diagnostic challenge due to the limitation of a congruent clinical or hematological picture. A thorough histological examination with immunofluorescence and electron microscopy often precipitates in the right diagnosis and prompts timely management.

Background: Tuberculosis (TB) of posterior pharyngeal wall (PPW), either primary or secondary, is extremely rare and can mimic malignancy in elderly patients.Case Report: A 36-year-old female patient presented with complains of nonhealing ulcer at the back of her throat for 4 months. On examination, there was an ulceroproliferative growth covered with slough over PPW. Positron emission tomography scan showed uptake in PPW. There was no uptake in any other part of body. A biopsy from PPW lesion showed epithelioid cell granulomas with Langhans type giant cells. Auramine-rhodamine staining showed few beaded bacilli consistent with TB.Conclusion: Tuberculosis of PPW is an extremely uncommon entity and can mimic malignancy. It should be kept as one of the differential diagnosis as it can be cured solely by giving anti-tubercular therapy.

Introduction:Mucosal-derived galactose-deficient IgA is central to the pathogenesis of primary IgA nephropathy (IgAN). Recent reports suggest similar pathogenesis in Henoch-Schonlein purpura (HSP) and secondary IgAN. Its role in other IgA-containing glomerular diseases is still under investigation. It can be detected in glomeruli with the recently described antibody KM55. We aimed to evaluate the role of KM55 by immunostaining a wide spectrum of IgA-containing glomerular diseases. Methods:After standardization and colocalization in a case of IgAN, a spectrum of 60 cases including IgAN, HSP, chronic liver disease (CLD)-related IgAN, other secondary IgAN, IgA-dominant/codominant membranoproliferative glomerulonephritis (MPGN), and lupus nephritis were subjected to immunofluorescence with KM55. KM55 was used to resolve diagnostic dilemma in cases of IgA deposition with confounding histology. Results:The group of primary IgAN (17 cases), HSP (4 cases), and secondary IgAN (19 cases) including CLD showed 2–3+ granular staining with KM55, suggesting mucosal-derived IgA. In contrast, cases of IgA-dominant/codominant MPGN (8 cases) and lupus nephritis (12 cases) were negative for KM55, suggesting systemic derivation of IgA. In cases of IgA deposition with confounding histology such as membranoproliferative or diffuse endocapillary proliferative pattern, KM55 helped to resolve the diagnosis. Discussion/Conclusion:This cross-sectional study concludes that KM55 is useful in the evaluation of IgA-containing glomerular diseases from a pathogenetic perspective and is a practical tool in resolving differential diagnosis in cases with overlapping histopathological features.

Introduction:Anti-GBM nephritis in the pediatric age group is exceedingly rare with concurrent additional pathologies being even rarer. Tissue diagnosis requires a combination of crescentic histomorphology, immunofluorescence showing “paint brush stroke” pattern of linear IgG or rarely IgA, and serum anti-GBM antibodies subject to the disease course and treatment. The authors describe one such case with a dual pathology involving IgA nephropathy and atypical anti-GBM disease. Case Presentation:A 13-year-old girl presenting with features of rapidly progressive glomerulonephritis underwent a renal biopsy showing a mesangioproliferative histology with crescents and an immunofluorescence pattern indicating a dual pathology of IgA nephropathy and anti-GBM nephritis. Additional ancillary testing including staining for IgG subclasses and galactose-deficient IgA (KM55) helped to confirm the diagnosis. She responded to steroid pulses and plasma exchange therapy, was off dialysis after 8 weeks with a serum creatinine level of 1.5 mg/dL, and however remains proteinuric at last follow-up. Conclusion:Concurrent anti-GBM nephritis and IgA nephropathy is a rare occurrence and possibly arises from a complex interaction between the anti-GBM antibodies and the basement membrane unmasking the antigens for IgA antibodies. Additional newer techniques like immunofluorescence for KM55 are helpful in establishing the dual pathology.

Primary Ewing sarcoma/primitive neuroectodermal tumor is a group of rare aggressive tumors in adults derived from neuroectoderm, and primary renal involvement is extremely rare. We describe an 18F-FDG PET/CT findings of a 28-year-old man who presented with left renal mass with inferior vena cava thrombus, which turned out to be primary Ewing sarcoma on histopathology specimen post left nephrectomy.

Paraffin immunofluorescence is a well established “salvage” technique in renal pathology when representative glomeruli are not found in the fresh frozen tissue sent for routine direct immunofluorescence studies. A step of enzymatic digestion of the formalin-fixed paraffin-embedded biopsy exposes the antigenic immune complexes and allows staining with fluorochrome-tagged antibodies. We explored the utility of the technique of paraffin immunofluorescence outside the kidney in certain specific scenarios including extra renal amyloid and duodenal macroglobulinemia.

Background Aggressive fibromatosis (AF) is a benign tumor that usually has a locally aggressive and recurrent disease course. Reports of association between AF and malignancies have been reported infrequently.Case We report a case of a 49-years lady who had papillary thyroid carcinoma associated with a distinct desmoid tumor occurring concurrently on the right side of the neck. Initial management comprised of total thyroidectomy followed by radio-iodine therapy and desmoid tumor resection. Recurrent AF developed at the same site as before after 2 years of resection. The recurrent tumor was managed with sorafenib, the patient responded with a resolution of symptoms, and the tumor remained stable. Beta-catenin mutation done by Sanger sequencing was negative in the tumor specimen.Conclusion AF can occur as a separate tumor in association with PTC. If symptoms are not life-threatening medical management may be a better choice in management.

Pleomorphic myxoid liposarcoma (PML) is a newly recognized entity with aggressive clinical behavior and a tendency to recur. It has histological features of both myxoid and pleomorphic liposarcoma and lacks the molecular and structural chromosomal abnormalities associated with myxoid and pleomorphic liposarcoma. The data about their response to chemotherapy is quite sparse. We report a case of incidentally detected pleomorphic myxoid liposarcoma of the mediastinum in a 32-year-old gentleman. After resection and adjuvant chemotherapy with doxorubicin and ifosfamide, there was no evidence of residual disease at the end of treatment. During a routine follow-up 5 months later, he was found to have a recurrence of the disease with histological confirmation. He received a trabectedin given its activity in myxoid liposarcoma. However, he had toxicities and progression leading to its discontinuation. Subsequently, eribulin was started as the next line of therapy. After 4 cycles of chemotherapy, response assessment was suggestive of partial response, which is still maintained after 7 cycles of eribulin. This is the first report of this entity responding to a newer chemotherapy regimen.

Isolated pancreatic metastasis from choroidal melanoma is a rare phenomenon. We describe a case of a 38-year-old woman who underwent enucleation surgery for right choroidal melanoma and subsequently developed lesions in the pancreas 10 years after enucleation, which were depicted on 68Ga-DOTANOC PET/CT and confirmed to be metastasis from choroidal melanoma on surgical histopathology.

Xanthogranulomatous pyelonephritis (XP) is a rare form of chronic pyelonephritis characterized by granulomatous inflammation extending to the perirenal soft tissues leading to destruction of the renal parenchyma. A rare presentation of XP as a chronic discharging fistula in a nine-year-old child is being reported. This report also reviews the literature to highlight the clinical features and management aspects of XP in children.

Introduction Primary intravenous leiomyosarcomas are rare vascular tumors with aggressive disease biology. The diagnosis and management have been challenging as little data exist from large databases.Methods A literature search was done to identify all cases of primary leiomyosarcomas in the last five years. Clinicopathological features and management strategies were evaluated.Results The median age was 53 years, predominantly females (2.5:1), presenting as metastases in up to 12.1% cases. Most tumors were locally advanced with a median size of 10cm. Inferior vena cava involvement from renal veins to infrahepatic veins remains the most frequent site (57.1%cases) while nearly half (52.8%) proceeded for surgery without histological proof. Most patients could undergo upfront resection (88.0%) with few patients receiving neoadjuvant chemotherapy (4.3%) or neoadjuvant radiotherapy (2.2%). Significant multivisceral resections included right nephrectomy (41.3%), liver resection (25.7%) and left nephrectomy (2.2%). Most patients (91.8%) needed an inferior vena cava graft placement with remarkable microscopically negative margins (85.5% cases). Doxorubicin and ifosfamide were the most frequently used combination chemotherapy regimens in both pre and postoperative settings with partial responses. The median overall and disease free survival among operated patients was 60 months and 28 months respectively. In multivariate analysis large tumor, extensive inferior vena cava involvement, and need for adjuvant chemotherapy appeared significant predictors for overall survival.Conclusions Aggressive upfront surgical resection with clear margin remains the key for long-term survival. Doxorubicin-based regimens were preferred as neoadjuvant chemotherapy while adjuvant treatment with chemotherapy, radiotherapy, or both may be considered in high-risk patients.