Phospholipase A2 receptor-negative membranous nephropathy presenting as a rare renal manifestation of IgG4-related disease.

IgG4-related disease is a fibroinflammatory condition characterized by dense lymphoplasmacytic infiltrates rich in IgG4-positive plasma cells affecting multiple organs. Though the most common renal manifestation of IgG4-related disease is tubulointerstitial nephritis, it can rarely present as secondary membranous nephropathy. We present a case of a 75-year-old male with phospholipase A2 receptor-negative membranous nephropathy as an atypical manifestation of IgG4-related disease. The patient presented with nephrotic syndrome and was found to have elevated serum IgG4 levels and IgG4-positive plasma cells in the kidney biopsy. He was successfully treated with corticosteroids and rituximab, resulting in significant improvement in proteinuria and normalization of IgG4 levels. This case highlights the importance of considering IgG4-related disease in patients with phospholipase A2 receptor-negative membranous nephropathy, especially in those with a history of other organ involvement. Early recognition and treatment of IgG4-related disease are crucial to prevent progressive kidney damage and improve patient outcomes.

Recurrent Metastatic Chordoma to the Liver: A Case Report and Review of the Literature.

Chordoma is a rare malignant neoplasm derived from notochordal tissue that primarily affects the axial skeleton. Almost 40% of patients have non-cranial chordoma metastases. The most common metastatic sites are the lungs, bones, lymph nodes, and subcutaneous tissue. We present a 52-year female with a history of sacral chordoma presenting with abdominal fullness, early satiety, and a palpable abdominal mass. Abdominal magnetic resonance imaging (MRI) revealed an isolated, highly vascularized, and multilobed liver mass in the left lateral segment. The mass was surgically removed using a clean surgical margin. A histological examination and immunohistochemical staining were consistent with a metastatic chordoma. Two years later, follow-up imaging studies showed a 6.5 × 4.0 × 2.0 cm right liver lesion with multiple lungs, chest wall, pleural, and diaphragmatic lesions. Microscopic- and immunohistochemical staining revealed a recurrent metastatic chordoma. Herein, we present a unique case of metastatic recurrent chordoma in the liver with the involvement of other sites. To the best of our knowledge, no other case of recurrent liver metastasis has been reported.

The Role of Serial Liquid Biopsy in the Management of Metastatic Non-Small Cell Lung Cancer (NSCLC).

Lung cancer is the leading cause of cancer-related deaths. Surgery remains the best option to treat lung cancer when feasible. However, many cases are diagnosed beyond the initial stages. There has been tremendous progress in the treatment of lung cancer over the last few years. Studies have shown that biomarker-driven targeted therapies lead to better outcomes. Due to the technical difficulties and significant procedural risk associated with repeated tissue biopsies, analysis of tumor constituents circulating in the blood, such as circulating tumor DNA (ctDNA) and various proteins, is becoming more widely recognized as an alternative method of tumor sampling, i.e., liquid biopsy. Liquid biopsy is superior to tissue biopsy, as it is minimally invasive and easily repeatable. Given the recent data on changes in mutations as the disease progresses or responds to treatment, liquid biopsies can help monitor the changes and guide us in giving targeted drugs. Here we present a case of advanced NSCLC who was initially started on Alectinib based on positivity for ALK gene rearrangement found in the FISH study. At the time of progression, molecular profiling liquid biopsy was obtained, which revealed KRAS-p.G12C mutation. Thus, the patient's therapy was later on changed to sotorasib after the FDA approved a KRAS-p.G12C mutation inhibitor.

Advances in the Treatment of Mucoepidermoid Carcinoma.

Mucoepidermoid carcinoma (MEC) represents 10-15% of salivary neoplasms. Due to their low incidence, it is challenging to conduct clinical trials and develop treatment guidelines. Although surgery is the most common approach for a resectable tumor, various treatment options such as chemotherapy, radiotherapy, and immunotherapy have been investigated. There is a need to implement a standardized treatment protocol to effectively manage MEC as it is a common histological subtype. Furthermore, it has become essential to assess chromosomal and genetic abnormalities recently identified with MEC, including alterations of CDKN2A, TP53, CDKN2B, BAP1, etc. These mutations are involved in the transformation of low-grade tumors to high-grade tumors, presenting a vital tool for evaluating the aggressive behavior of this carcinoma. Detailed immunohistochemical and translocation studies can help develop targeted therapies and monitor treatment response. Therefore, biomarker-driven research will immensely improve the outcome, especially in advanced cases. Based on thorough histology and chromosomal translocations, a more personalized treatment plan can improve the overall disease outcome. The purpose of this article is to elaborate on the current treatment advancements, particularly chemotherapy and targeted therapy, as an effective treatment modality for the management of MEC and highlight the comparison with traditional treatment approaches.

Retraction: Idiopathic CD4+ Lymphocytopenia Due to Homozygous Loss of the CD4 Start Codon.

[This retracts the article DOI: 10.7759/cureus.15251.].

Idiopathic CD4+ Lymphocytopenia Due to Homozygous Loss of the CD4 Start Codon.

Idiopathic CD4+ lymphocytopenia (ICL) is an extremely rare condition characterized by low numbers of CD4+ cells (<0.3 K/µL) without human immunodeficiency virus (HIV) infection or any other cause of immunodeficiency. In this case report, we report a case of idiopathic CD4+ lymphocytopenia in a 22-year-old woman initially presenting with insomnia, fatigue, and a sore throat. However, this rapidly progressed to shortness of breath and chest pain, ultimately leading to acute respiratory distress syndrome (ARDS) over the span of a few days. Broad-spectrum antimicrobials were administered, resulting in prompt recovery. Serological studies were negative for malignancy and severe infections, including HIV1 and HIV2. Flow cytometry revealed an absence of CD4+ cells and an increase in double-negative T-cells. Further genetic workup revealed that in the second exon of the CD4 gene, the patient had a homozygous c.1ATG>GTG (p.Met1Val; p.M1V) mutation. Family screening showed that the patient's mother, father, and brother all had a single p.M1V mutation, allowing for deleterious effects to be partially offset by the normal copy of the gene. We have provided an organized analysis of the existing literature in addition to a concise overview of this case, with the intention of identifying patterns in presentation, clinical course, and outcomes. This case discusses the effects of the loss of the CD4+ start codon in the patient. Although this specific form of lymphocytopenia is very uncommon, it illustrates the importance of genetic testing and the integral nature of laboratory testing in therapy charting.