Fever Of Unknown Origin Research Articles

Retrospective study on clinical value and optimal use of [18F] FDG PET/CT for inflammation of unknown origin in Japanese patients.

Despite advancements in medical technology, the challenges of diagnosing fever of unknown origin (FUO) and inflammation of unknown origin (IUO) persist. Positron emission tomography/computed tomography (PET/CT) has been used to assess these conditions; however, it is unclear which patients most benefit from this approach. This study aimed to assess the clinical value and optimal use of fluorine-18-labelled-fluorodeoxyglucose (18F-FDG)-PET/CT in patients with FUO/IUO. We reviewed FDG-PET/CT scans conducted at our department between January 2014 and December 2020 to further assess FUO/IUO. FUO was defined as a fever lasting over three weeks without a diagnosis based on conventional assessment. IUO was defined as prolonged inflammation with a body temperature below 38.3 ℃ and without a diagnosis after conventional diagnostic procedures. The efficacy of FDG-PET/CT was determined based on the diagnostic outcomes achieved by integrating imaging findings with histopathological or microbiological evidence, clinical criteria, or follow-up assessments. We conducted crude and age-sex adjusted logistic regression for potential risk factors to determine the degree of burden on demographic and clinical characteristics. Forty-five patients with FUO/IUO underwent FDG-PET/CT, and final diagnoses were made in 32 patients (71.1%). The percentages of diagnostic categories were 53.3%, 8.9%, and 6.7% for non-infectious inflammatory diseases, malignancy, and infection, respectively. In multivariable logistic regression analysis, IUO was the only independent predictor of the efficacy of FDG-PET/CT in the final diagnosis (odds ratio, 67.02; 95% confidence interval, 4.02-1119). Our results indicate that IUO was associated with a higher diagnostic yield compared to those with FUO.

Clinical impact of ceftazidime/avibactam on the treatment of suspected or proven infections in a large cohort of patients with haematological malignancies: a multicentre observational real-world study.

To evaluate clinical impact of ceftazidime/avibactam on treating infections due to MDR Gram-negative bacteria in patients with haematological malignancies (HMs). We conducted a retrospective, observational study at 17 Italian haematological wards that included patients with HMs receiving ceftazidime/avibactam for the treatment of suspected or proven infections. The primary endpoint was all-cause mortality 30 days after infection onset. Secondary endpoints included the development of in vitro ceftazidime/avibactam resistance, adverse reactions and infection relapse. Of 198 patients enrolled, 66 had fever of unknown origin and 132 had microbiologically proven infections (MPIs). Enterobacterales were responsible for 98 MPIs, with KPC producers accounting for 75% of these, and carbapenem-resistant Pseudomonas aeruginosa caused 25% of MPIs. The overall 30-day mortality rate was 17.7%. Infection relapse occurred in four patients with MPI. Patients who died within 30 days of infection onset tended to have pre-existing cerebrovascular diseases, a Charlson Comorbidity Index > 4 and septic shock at infection onset and had received inadequate initial antibiotic therapy. Thirty-day mortality was independently associated with septic shock at infection onset and inappropriate initial antibiotic therapy. Our study provides further evidence about the effectiveness of ceftazidime/avibactam in treating infections in patients with HMs.

Distinguishing lymphoma from benign lymph node diseases in fever of unknown origin using PET/CT radiomics.

A considerable portion of patients with fever of unknown origin (FUO) present concomitant lymphadenopathy. Diseases within the spectrum of FUO accompanied by lymphadenopathy include lymphoma, infections, and rheumatic diseases. Particularly, lymphoma has emerged as the most prevalent etiology of FUO with associated lymphadenopathy. Distinguishing between benign and malignant lymph node lesions is a major challenge for physicians and an urgent clinical concern for patients. However, conventional imaging techniques, including PET/CT, often have difficulty accurately distinguishing between malignant and benign lymph node lesions. This study utilizes PET/CT radiomics to differentiate between lymphoma and benign lymph node lesions in patients with FUO, aiming to improve diagnostic accuracy. Data were collected from 204 patients who underwent 18F-FDG PET/CT examinations for FUO, including 114 lymphoma patients and 90 patients with benign lymph node lesions. Patients were randomly divided into training and testing groups at a ratio of 7:3. A total of 15 effective features were obtained by the least absolute shrinkage and selection operator (LASSO) algorithm. Machine learning models were constructed using logistic regression (LR), support vector machine (SVM), random forest (RF), and k-nearest neighbors (KNN) algorithms. In the training group, the area under the curve (AUC) values for predicting lymphoma and benign cases by LR, SVM, RF, and KNN models were 0.936, 0.930, 0.998, and 0.938, respectively. There were statistically significant differences in AUC between the RF and other models (all P < 0.001). In the testing group, the AUC values for the four models were 0.860, 0.866, 0.915, and 0.891, respectively, with no statistically significant differences observed among them (all P > 0.05). The decision curve analysis (DCA) curves of the RF model outperformed those of the other three models in both the training and testing groups. PET/CT radiomics demonstrated promising performance in discriminating lymphoma from benign lymph node lesions in patients with FUO, with the RF model showing the best performance.

An 18-Month Case of Langerhans Cell Histiocytosis : Diagnostic Challenges and Treatment Outcome

Background: Langerhans Cell Histiocytosis (LCH) is a rare disorder characterized by the abnormal proliferation of Langerhans cells, which can affect various tissues and organs, often mimicking malignancies. It primarily affects children and can present with a wide range of symptoms, making diagnosis challenging. The etiology of LCH remains uncertain, though recent studies suggest it involves the aberrant growth of Langerhans cells triggering an immune response. Case Presentation: This was a case of an 18-month-old boy who came with fever of unknown origin in the Department of Paediatrics at BBMH who later on diagnosed as Histiocytosis. Conclusion: This case highlights the importance of considering LCH in the differential diagnosis of paediatric patients presenting with systemic symptoms such as fever, organomegaly and anaemia. Early recognition and appropriate treatment, including chemotherapy and corticosteroids are crucial for favourable outcomes. Continuous follow-up is necessary to monitor therapeutic response and manage potential complications. This report contributes to the understanding of LCH and underscores the need for further research into its etiology and treatment protocols. IAHS Medical Journal Vol 7(1), June 2024; 102-104

Clinical Presentation of Cat Scratch Disease in Pediatric Patients-A Single-Center Study.

Cat scratch disease (CSD) is the infectious disease caused by Bartonella henselae. Its typical presentation is regional lymphadenopathy. Also it may present with symptoms related to involved organs or disseminated disease with fever of unknown origin (FUO). Here children with CSD are evaluated to increase awareness about disease. A total of 29 children diagnosed with CSD between 2019 and 2022 were involved in the study. Patients' demographic characteristics, clinical, laboratory and radiological findings, treatments, and outcomes were analyzed. Seventeen of the patients were male, 12 were female, and their mean age was 116.5 ± 51 months. About 69.6% of them had a history of cat contact. Twenty-seven patient (93.1%) had lymphadenopathy, mostly axillary involved (61.5%). Other manifestations were disseminated disease presented with FUO, neuroretinitis, and encephalopathy. Twenty-seven patients (93.1%) had received antibiotics before admission without any improvement. Ultrasound showed that the affected lymph nodes were conglomerated, lobulated contoured, and cortical thickened, with one-third having cystic suppurative components. Serologic tests were positive in 24 of 27 patients. Twenty-one patients gave response to 5 days azithromycin treatment, in 8 patients this treatment extended to 10-14 days, rifampicin with/without doxycycline was given to 6 patients, and steroids were given to 3 patients. In case of regional lymphadenopathy, especially axillary, not responding to nonspecific antibiotics CSD should be suspected. Cat contact history and serological and ultrasonographic findings are useful for diagnosis. Even if CSD responds well to azithromycin, sometimes prolongation of azithromycin and addition of other antibiotic or steroid may be required.

P35 Pyrexia of unknown origin in a patient with long standing rheumatoid arthritis

Abstract Introduction Pyrexia of unknown origin (PUO) can be challenging in treated rheumatic auto-immune disease. Many conditions may have fever as part of the symptom complex, treatment may mask signs and symptoms and can also make opportunistic infection more likely. Unusual or fastidious infections can be particularly difficult to diagnose. We describe a case of ureaplasma infection that evaded detection for a prolonged period in a female with long standing rheumatoid arthritis (RA). Case description 47 year old female presented January 2023 with fevers, weight loss and persistently high CRP. RA diagnosed in 1998. Erosive wrist and MTP disease, initial RF 32, CCP 8. Treatment- 5-10 mg prednisolone since 1998, adalimumab 2010, rituximab 2013-2022. Normal Ig levels, IgG lamda paraprotein since 2016 (too low to quantify). Frequency and dysuria March 2022. Cystoscopy- small bladder; biopsies in May 2022 and August 2023 showed acute on chronic inflammatory infiltrate with granulation tissue. Interstitial cystitis diagnosed. She had recurrent episodes of pyuria and was given several courses of antibiotics, including meropenem, temocillin, fluconazole, gentamicin. Despite the recurrent pyuria no organisms were cultured. CT CAP February 2023 -ground glass opacity right lower lobe. Later CXR clear. Quantiferon negative, also negative 2016, 2019. Other normal / negative tests- TTG, HIV, Hep ABCE, TFTs, EBV viral load. EBV, CMV IgG +ve. CMV titres 696 c/ml June 2023. CD 19 undetectable. IgG4 0.02 g/L. MPO, PR3 negative. BK virus was detected in urine. There was no sustained response to iv methylprednisolone and a course of filgotinib given for possible systemic RA symptoms. She developed a dry cough and shortness of breath. PET-CT July 2023 - bilateral FDG avid large confluent areas of consolidation. Urine + bronchial washings were negative for TB growth at 42 days. However, in view of deterioration empirical TB treatment was started July 2023. CT urogram in September 2023 showed likely bilateral renal abcesses, as well as bilateral hydronephrosis. Left renal cyst aspirate was performed and empirical doxycycline started at 100 mg bd. Ureaplasma detected from the aspirate on PCR. 3 weeks doxycyline given with rapid resolution of fevers and CRP. February 2024- cystectomy and ileal conduit in for refractory interstitial cystitis with a poorly compliant, small capacity, thick walled fibrotic bladder which had caused bilateral ureteric obstruction. She has made a good recovery. TB treatment course was completed. Discussion This case shows the difficulties in diagnosing infection from a little known and difficult to detect organism, ureaplasma. Discovered in the 1950s, it has no cell wall and very small genome and is therefore an obligate parasite /saprophyte. Together with mycoplasma it belongs to the bacterial class of Mollicutes. It cannot be routinely cultured nor gram stained. PCR or specialist culture is required. It may be present as a commensal but has been implicated in symptomatic genitourinary infections. It has also been implicated in native and non-native joint infections, and in infants can cause a pneumonic illness. Empirical treatment may be indicated due to long turn around times for diagnosis. There is some evidence that reduced humoral immunity may be a contributory factor to infection. We have found a previous case described of ureaplasma renal abcesses in a patient with MS and neurogenic bladder treated with rituximab. Our patient had normal immunoglobulin levels though still had profound CD19 suppression. Further immune suppression resulted from methylprednisolone and course of filgotinib, which may have accelerated the course of infection. Ureaplasma and mycoplasma do not have a cell wall, thus making beta-lactam antibiotics and vancomycin ineffective. Cyclines, josamycin and fluroquinolones are effective, though there is increasing resistance developing. We gave a relatively long course of doxycycline as our patient was very unwell and had apparent extensive urinary tract involvement. BK virus seropositivity is present in 90% of the normal population and asymptomatic viruria in up to 20%. However, it is a cause of renal tract inflammation in the immunosuppressed – in particular post-transplant. We felt it was unlikely to be significant in our patient in view of the clinical picture, lack of BK viraemia and negative viral findings on bladder biopsy. Key learning points • Ureaplasma should be on the list of organisms to consider in cases of PUO when the more common infective causes have been ruled out, particularly in immune suppressed patients. Patience and close collaboration with colleagues is essential. This patient had multiple MDT meetings involving infectious disease, respiratory, secondary and tertiary care urology and rheumatology specialists. The collaboration was invaluable. A course of doxycycline may be considered as a relatively low risk approach while awaiting microbiological confirmation in such cases.

Fever management in children and insights into fever of unknown origin: a survey among Italian pediatricians

Fever management in children and insights into fever of unknown origin: a survey among Italian pediatricians

The Efficacy of Total Compilation in the Treatment of Fever of Unknown Origin

Pyrexia of unknown origin (P. U. O.) is defined as fever of unknown origin with a temperature that is more than 101°F, with duration of more than 3 weeks. In cases where patients have chronic fevers but the investigation do not show anything disastrous, one need not to panic.

Baricitinib in polymyalgia rheumatica and giant cell arteritis: report of six cases.

The objective of this case series is to describe the efficacy and safety of baricitinib (BARI) in a group of patients with polymyalgia rheumatica (PMR) and/or giant cell arteritis (GCA). These patients were treated with BARI due to either a refractory disease course or the unavailability of tocilizumab because of the pandemic. A total of six patients (five females and one male, median age 64 years, range 50-83) were treated with BARI. Two of them had isolated PMR, two had PMR with associated large vessel (LV)-GCA, one had LV-GCA presenting as fever of unknown origin, and one had cranial-GCA. All patients reported improvement with BARI. At the time of starting BARI, patients were taking a median prednisone dose of 8.75 mg/day (range 0-25), and the four patients with PMR had a median PMR-AS of 23.3 (indicating high disease activity), which decreased to 1.58 after 6 months of treatment with BARI. Two of them could stop glucocorticoids (GC) and continued BARI monotherapy. One patient suffered from pneumonia, and BARI was therefore stopped. No other adverse events attributable to BARI were detected. Our case series supports previous reports suggesting efficacy of Janus kinase inhibitors as a GC-sparing strategy in PMR and GCA.

Ovarian carcinosarcoma with lung metastasis characterized by persistent fever: A case report and literature review.

Ovarian carcinosarcoma (OCS) is a rare malignant tumor prone to distant metastasis. Primary manifestations include pelvic and/or abdominal pain, bloating, and compression. Nevertheless, it is uncommon for OCS to present primarily with persistent fever. This is the first reported case of OCS with lung metastasis characterized by persistent fever. A 61-year-old female patient complaining of abdominal pain and fever was admitted to our hospital. Computed tomography showed an irregular, slightly low-density mass on the left side of the uterus and multiple solid nodules in both lungs. She underwent cytoreductive surgery for pathologically confirmed stage IVB OCS. She was administered chemotherapy after cytoreductive surgery. Given the patient's history of persistent fever and progressively enlarged pulmonary nodules, a pulmonary abscess was considered as a possible diagnosis. Following antibiotic therapy, the patient's high body temperature did not decrease; however, following nonsteroidal anti-inflammatory drug therapy, it quickly decreased. These symptoms were eventually considered the consequence of neoplastic fever caused by lung metastases. Owing to the rapid progression of the disease, the patient ultimately died. This study suggests that, for patients with pelvic and/or abdominal pain, bloating, and pelvic masses, especially those with suspicious lesions in other organs accompanied by fever of unknown origin, a diagnosis of cancer or sarcoma with metastasis should be considered after ruling out infectious fever.

Difficulties in Diagnosing a Patient with Fever of Unknown Origin

Fever of unknown origin is a difficult syndrome for differential diagnosis. Absence of a key feature, variety of causes and the lack of single examination algorithm makes difficult further diagnosis. The presented clinical case describes a 53-year-old patient with a prolonged fever of more than 1.5 months, pain syndrome in the facial area. During outpatient monitoring, the cause was not clarified. At the inpatient stage, a comprehensive examination was conducted for all classes of causes. The revealed changes in the thyroid gland and thyrotoxicosis made it possible to diagnose subacute thyroiditis. According to the literature, subacute thyroiditis is one of the rare causes of fever of unknown origin. Prescription of glucocorticosteroid made it possible to achieve complete regression of clinical symptoms in 4 days. After 5 months, subclinical hypothyroidism was achieved. The nosological approach and multidisciplinary interaction contributed to the correct tactics and a favorable outcome of the disease.

Fever of Unknown Origin in Children

Fever is a common symptom in children and fever of unknown origin (FUO) is not uncommon in paediatric age group. The FUO remains a challenging clinical problem and is an important cause of morbidity and mortality in children. These undifferentiated prolonged fevers need step-wise approach for diagnosis. Details and proper history taking, thorough serial physical examination, critical analysis of sign-symptoms diary and investigation reports are crucial to get a clue that led to the diagnosis. Though in some aspect more concerned with developing countries data, this article is based on reviewing of published papers from both developed and developing countries. Worldwide infection remains the most common cause of FUO in children, followed by collagen vascular diseases, neoplasm, miscellaneous diseases and undiagnosed illnesses. Indiscriminate use of antimicrobials and other medications may mask the real diagnosis. Awareness of primary-level healthcare providers about the cause and logical management approach of pediatric FUO is important for better outcome. Journal of Monno Medical College December, 2023; 9 (2):78-84

A case report of fatal Rickettsia japonica bloodstream infection in Zhejiang, China.

Japanese spotted fever (JSF) is an emerging acute febrile natural infectious disease caused by the neglected zoonotic pathogen Rickettsia japonica. Here we reported a 64-year-old female patient who initially presented to the local hospital with an intermittent fever of unknown origin (FUO). A systemic, evident edema and eschar on the skin of the patient's upper limb was observed. The patient was diagnosed with critical Rickettsia japonica bloodstream infection by Q-mNGS and treated with doxycycline, as well as symptomatic treatments. Unfortunately, the patient passed away as a result of complications of septic shock and multiple organ and acute respiratory failure. Delayed treatment resulting from the nonspecific clinical symptoms in the early stages of infection can lead to fatal complications. Q-mNGS is an emerging pathogen detection method with the advantages of comprehensive detection, high accuracy and sensitivity and should be promoted and applied by clinicians.

First molecular diagnosis of the human pathogen Rickettsia raoultii and other spotted fever group rickettsiae in Sudanese ixodid ticks from domestic ruminants.

Rickettsial infections are often neglected and poorly recognized by physicians in many tropical and subtropical regions. Despite a number of recent reports describing rickettsial diseases in new locations and the discovery of new rickettsiae, medical science and research have largely neglected the diagnosis and antimicrobial treatment of rickettsial infections in subtropical and tropical areas; thus, much remains to be discovered. This study aimed to detect and characterize spotted fever group (SFG) rickettsiae in ixodid ticks infesting domestic ruminants in Khartoum State. Polymerase chain reaction targeting both genes that encode for citrate synthase (gltA) and outer membrane protein (ompA) was performed for the presence of SFG rickettsia followed by sequence and phylogenetic analysis. Of the 202 ticks examined for the presence of SFG rickettsia, gltA gene was detected in 4 samples (2%). Furthermore, gltA-positive samples were used to amplify the ompA gene, in which only two samples yielded positive results. Sequence and phylogenetic analysis of the positive samples revealed four different species of SFG rickettsiae: Rickettsia aeschlimannii, Rickettsia rhipicephali, Rickettsia massiliae and Rickettsia raoultii. These results indicated the presence of SFG rickettsia in Sudanese ticks. This also indicates that humans have an opportunity to acquire these infections. It is important to keep in mind the need for careful consideration of rickettsial infections in individuals with a fever of unknown origin.

Co-Infection of Cytomegalovirus and Leishmania without Splenomegaly Resulting in Immunosuppression in an Hiv-Negative Patient.

Leishmaniasis is caused by the parasite Leishmania donovani and transmitted by the bite of the sand fly vector Phlebotomus. This disease is endemic in the Bihar region of India. There are three common forms of the disease - cutaneous, mucosal and visceral leishmaniasis. The most common presentation of this disease is prolonged unexplained fever with hepatosplenomegaly. We report an unusual case of pyrexia of unknown origin (PUO) in a patient who was extensively worked up for PUO. She was found to have low CD4 counts even though serial samples were negative for HIV. Workup for PUO revealed a positive result for cytomegalovirus (CMV) IgM and polymerase chain reaction (PCR), fundoscopy suggestive of CMV retinitis and bone marrow biopsy suggestive of visceral leishmaniasis. Interestingly, there was no evidence of hepatosplenomegaly. She was diagnosed as a case of CMV infection and visceral leishmaniasis resulting in immunosuppression and was managed with parenteral ganciclovir followed by oral valganciclovir and amphotericin respectively. She had a dramatic response to the treatment and was discharged after two months of in hospital management. Co-infection of CMV and Leishmania in an immunocompromised patient with HIV-negative status without hepatosplenomegaly posed a diagnostic dilemma and is a rare presentation. This report shows the importance of diagnosis of this co-infectious state, which upon management with ganciclovir and amphotericin lead to resolution of symptoms and pancytopenia. Clinicians should be aware of the unusual presentation to avoid missing the diagnosis of this potentially life-threatening treatable condition. Visceral leishmaniasis without splenomegaly is a rare presentation.Other aetiologies for low CD4 counts in an HIV-negative patient such as cytomegalovirus (CMV) should be considered.Co-infection of CMV and Leishmania resulting in immunosuppression in an HIV-negative patient is rare and poses a diagnostic dilemma.

Neutrophil-to-ferritin ratio can predict hematological causes of fever of unknown origin

Despite advancements in diagnostic modalities, delineating the etiology of fever of unknown origin (FUO) remains a significant challenge for clinicians. Notably, cases with hematological malignancies often have a poor prognosis due to delayed diagnosis. This study investigated the potential of readily obtainable laboratory markers to differentiate hematological causes from other etiologies during the early stages of FUO. A retrospective analysis was conducted on the medical records of 100 patients who fulfilled the modified FUO criteria between January 2010 and April 2023. Hematological etiologies were identified in 26 of the 100 patients. Peripheral blood neutrophil, lymphocyte, platelet counts, and the systemic immune inflammation (SII) index, were significantly lower in the hematological group compared to the non-hematological group. Conversely, serum ferritin levels were demonstrably higher in the hematological group. ROC analysis identified a neutrophil-to-ferritin ratio (NFR) cutoff value of < 8.53 as optimal for predicting hematological etiology. Subsequent multivariate analysis demonstrated that the NFR was the sole independent predictor of hematological etiology (p = 0.013).This study proposes a novel approach for early diagnosis of a potentially life-threatening subset of FUO patients. The NFR presents as an inexpensive and readily available marker for predicting hematological etiology in FUO cases.

Summary: Appropriate Use Criteria for the Use of Nuclear Medicine in Fever of Unknown Origin.

The diagnostic work-up of patients with fever of unknown origin (FUO) begins with a thorough history and physical examination, complete blood count with differential, chest x-ray, urinalysis and culture, electrolyte panel, liver enzymes, erythrocyte sedimentation rate, and C-reactive protein level. Additional imaging procedures, including nuclear medicine tests, are generally used as second-line procedures, with 18F-FDG PET and PET/CT assuming increasingly important roles in the diagnostic work-up. The Society of Nuclear Medicine and Molecular Imaging, the Infectious Diseases Society of America, and the American College of Nuclear Medicine convened an autonomous expert work group to comprehensively review the published literature for nuclear imaging in adults and children with FUO and establish appropriate use criteria (AUC). This process was performed in accordance with the Protecting Access to Medicare Act of 2014, which requires that all referring physicians consult AUC by using a clinical decision support mechanism before ordering advanced diagnostic imaging services. The complete findings and discussions of the work group were published on January 8, 2023, and are available at https://www.snmmi.org/ClinicalPractice/content.aspx?ItemNumber=15666 The AUC in the final document are intended to assist referring health care providers in appropriate use of nuclear medicine imaging procedures in patients with FUO. The work group noted limitations in the current literature on nuclear medicine imaging for FUO, with the need for well-designed prospective multicenter investigations. Consensus findings from published data and expert opinions were used to create recommendations in common clinical scenarios for adults and children. Included in the complete document is a discussion of inflammation of unknown origin (IUO), a recently described entity. In view of the fact that the criteria for FUO and IUO are similar (except for fever > 38.3°C [100.9°F]) and that the most common etiologies of these 2 entities are similar, it is the expert opinion of the work group that the recommendations for nuclear medicine imaging of FUO are also applicable to IUO. These recommendations are included in the full guidance document. This summary reviews rationale, methodology, and main findings and refers the reader to the complete AUC document.

Abstract C069: Unraveling the complexity of malignant peritoneal mesothelioma: A comprehensive case study of diagnosis, clinical features, and therapeutic challenges in a 75-year-old male

Abstract Introduction: Malignant Peritoneal Mesothelioma (MPM) is a rare and aggressive intra-abdominal neoplasm originating from mesothelial cells. Although asbestos exposure is a known risk factor, MPM's molecular pathogenesis differs from its pleural counterpart. Case Presentation: A 75-year-old male, with a past medical history of recently diagnosed mesothelioma, presented to the emergency department for a two-week progression of abdominal distension, early satiety, and dyspnea aggravated by activity. One year prior, he initiated medical evaluation for fluid retention and abdominal distension. A recent omental biopsy confirmed the diagnosis of mesothelioma, prompting the initiation of chemotherapy every three weeks. Despite paracentesis performed monthly, the patient experienced worsening shortness of breath and early satiety post-chemotherapy. Discussion: Malignant Peritoneal Mesothelioma poses a diagnostic challenge due to the absence of specific signs or symptoms. Common manifestations include abdominal distension, pain, early satiety, weight loss, dyspnea, chest pain, and fatigue. Rare symptoms encompass new-onset hernia, fever of unknown origin, night sweats, or incidental findings during physical examinations or laparoscopy. Delays in presentation and diagnosis contribute to the advanced stage at diagnosis, with most cases having already spread throughout the abdominal cavity. Three distinct presentations of MPM include the Dry Painful Type, characterized by abdominal pain with minimal ascites; the Wet Type, presenting with abdominal distension and ascites; and the Mixed Type, combining abdominal pain and distension. Paraneoplastic phenomena, such as fever, thrombocytosis, malignancy-related thrombosis, hypoglycemia, hypoalbuminemia, paraneoplastic hepatopathy, and rarely, Coombs-positive Hemolytic anemia, further complicate the clinical picture. Surgical gross and microscopic descriptions of liver biopsies indicated chronic hepatitis with mild portal inflammation, grade 1, and no fibrosis, stage 0. Notably, the omental biopsy confirmed Malignant Mesothelioma of the epithelioid type. Immunohistochemical stains supported the diagnosis, revealing positivity for CK AE1/AE3, calretinin, WT1, CK7 (focally), and GATA3 (focally), while testing negative for BAP1, CDX2, chromogranin, CK20, hepatocyte antigen, PAX8, PSA, synaptophysin, and TTF1. Due to the rarity of MPM, no standardized treatment protocols exist. Cytoreductive surgery (CRS) and hyperthermic intraoperative peritoneal perfusion with chemotherapy (HIPEC) are recommended for selected patients without extraperitoneal disease spread, possessing a good performance status and potential for complete surgical cytoreduction. Systemic chemotherapy, particularly pemetrexed-based regimens, is advocated for patients ineligible for CRS/HIPEC. Conclusion: MPM's aggressive nature poses diagnostic and therapeutic challenges. The scarcity of standardized guidelines emphasizes the importance of ongoing research to enhance understanding, improve diagnostics, and develop targeted therapies Citation Format: Aliya M Khan, Mehmet Hepgur, Aryama Sharma. Unraveling the complexity of malignant peritoneal mesothelioma: A comprehensive case study of diagnosis, clinical features, and therapeutic challenges in a 75-year-old male [abstract]. In: Proceedings of the 17th AACR Conference on the Science of Cancer Health Disparities in Racial/Ethnic Minorities and the Medically Underserved; 2024 Sep 21-24; Los Angeles, CA. Philadelphia (PA): AACR; Cancer Epidemiol Biomarkers Prev 2024;33(9 Suppl):Abstract nr C069.

Fever of Unknown Origin in Children: A Single Center Experience from Southern Türkiye

Fever of Unknown Origin in Children: A Single Center Experience from Southern Türkiye

Performance and value of 18F‑FDG PET/CT in patients with fever of unknown origin.

Fever of unknown origin (FUO) is a common clinical and diagnostic challenge. The main aim of the present study was to evaluate the diagnostic accuracy of 18F-fluorodeoxyglucose (18FDG) positron emission tomography (PET)/CT in patients who present with FUO. Overall, 105 consecutive patients (61 men and 44 women) with a mean age of 51±35 years with FUO underwent 18FDG PET/CT scans. The performance of 18FDG PET/CT in determining the etiology of FUO was assessed. According to the PET/CT results, patients were classified into four groups: Group 1, patients with true-positive results (n=51; 49%), in whom abnormal 18FDG uptake identified the final diagnosis; group 2, patients with false-positive results (n=24; 23%), in whom 18FDG uptake was not consistent with the final diagnosis; group 3, patients with true-negative results (n=10; 9.5%), in whom the 18FDG uptake was normal and no final disease was established; and group 4, patients with false-negative results (n=20; 19%), in whom 18FDG uptake was normal and disease was finally established. Of the 51 patients with true-positive PET/CT results, 51% had infections, 35% had malignancies and 14% had inflammatory processes. The sensitivity, specificity, positive predictive value, negative predictive value and accuracy were 72, 29, 68, 33 and 58%, respectively. In conclusion, the present results demonstrated that 18FDG PET/CT established the final diagnosis of FUO in the majority of patients (72%). These results support the use of 18FDG PET/CT in the initial evaluation and management of patients with FUO.