A 27-month-old previously healthy girl presented with 3 months of cough and 1 day of fever and rhinorrhea. Her parents had immigrated from Africa, but our patient had been born in the United States and had no notable environmental exposures. An alarming chest radiograph suggested a broad differential diagnosis, and lung biopsy with pathology was ultimately required to confirm her rare diagnosis. Both her diagnosis and its significant implications are discussed.

Sarcoidosis is a multisystem granulomatous disease that can involve multiple organ systems, present with varied clinical features, and overlap diagnostically with malignancy and immune-mediated disorders. We report the case of a 39-year-old woman who presented with mild dyspnea, generalized weakness, and unintentional weight loss, accompanied by marked hypereosinophilia. Laboratory evaluation revealed a cholestatic pattern of liver injury, elevated total serum IgG, markedly elevated serum IgG4, elevated serum IgE, polyclonal hypergammaglobulinemia, and elevated serum angiotensin-converting enzyme levels. Cross-sectional imaging demonstrated marked hepatosplenomegaly with multiple nodular lesions, extensive abdominal and mediastinal lymphadenopathy, and bilateral subpleural pulmonary nodules. Given these findings, an infiltrative or malignant process was initially suspected. Excisional lymph node biopsy revealed non-necrotizing granulomatous inflammation consistent with sarcoidosis. Bone marrow aspiration and biopsy demonstrated preserved hematopoiesis without abnormal cellular infiltration, while acid-fast bacilli staining and mycobacterial cultures were negative, effectively excluding hematologic malignancy, tuberculosis, and primary hypereosinophilic syndromes. This case expands the limited literature on hepatic sarcoidosis presenting with marked hypereosinophilia and elevated serum IgG4, emphasizing the importance of histopathological confirmation and systematic exclusion of alternative diagnoses.

We report the case of a 60-year-old man who initially presented in October 2021 with a history of recurrent itchy skin lesions across exposed areas of his body such as the neck and extremities. As per history and clinical examination, the lesions were initially interpreted as an insect bite reaction for which the patient was provided with symptomatic treatment. Despite the treatment, the patient continued to experience recurrent skin lesions. Histopathologic exam of a skin biopsy showed eosinophil-rich superficial and deep inflammatory infiltrates which supported the diagnosis of a cutaneous reaction to an insect bite or another hypersensitivity-type reaction which further made the diagnosis challenging. In 2024, he developed systemic symptoms such as dizziness, vomiting, and generalized lymphadenopathy. Laboratory tests revealed significant leukocytosis with persistent lymphocytosis, mild anemia, and thrombocytopenia. A peripheral smear was done and showed mature lymphocytosis with smudge cells. Flow cytometry identified a clonal B-cell population expressing CD5, CD23, CD200, and lambda light-chain reaction, supporting a diagnosis of chronic lymphocytic leukemia. Positron emission tomography-computed tomography (PET-CT) demonstrated hypermetabolic lymphadenopathy above and below the diaphragm and hepatosplenomegaly. Cutaneous manifestations resembling different benign dermatologic conditions, such as an insect bite reaction, may rarely precede systemic symptoms of an underlying hematologic malignancy. This case emphasizes the significance of reassessment and follow-up in patients with recurrent and evolving dermatological findings.

Brucellosis is a common zoonosis worldwide, yet large-scale pediatric data are scarce. This nationwide multicenter study from Türkiye, a highly endemic country, aimed to characterize pediatric brucellosis and identify independent risk factors for complications, relapse, and hospitalization. A retrospective cohort was conducted across 32 hospitals between January 2019 and June 2024. Children aged 0-18 years with confirmed brucellosis were included. Data were analyzed by multiple backward logistic regressions, with Firth penalization for the complication and relapse models. A total of 1052 children were included (median age 12 years; 69.9% male). Complications occurred in 87 patients (8.3%), most frequently osteoarticular (spondylitis, sacroiliitis, and osteomyelitis), whereas neurobrucellosis was rare (0.9%); relapse occurred in 34 patients (3.2%). Complications were independently associated with headache (adjusted OR 3.566, 95% CI 1.861-6.637), arthralgia/arthritis, culture positivity, night sweating, and myalgia. Relapse was independently associated with female sex (adjusted OR 3.675, 95% CI 1.617-8.568), whereas treatment compliance was protective (adjusted OR 0.254, 95% CI 0.092-0.857). Hospitalization (34.1%) was independently associated with headache, diarrhea, hepatomegaly, lymphadenopathy, fever, elevated CRP, and lower hemoglobin, whereas diagnosis through household contact screening was protective. Conclusion: Pediatric brucellosis in Türkiye generally follows a favorable course, with low complication and relapse rates. Readily identifiable musculoskeletal and constitutional symptoms at presentation may help predict complicated disease, while treatment adherence remains the key determinant of relapse. Early detection through household contact screening may reduce disease burden in endemic regions. What is Known: • Brucellosis is a common zoonosis with limited pediatric data worldwide. Early detection and treatment adherence are critical for favorable outcomes. • Complications and relapse are recognized but poorly defined in children What is New: • This is one of the largest nationwide pediatric brucellosis cohorts reported to date, including 1052 children. Household contact screening shown protective against hospitalization. • Treatment adherence, rather than disease severity or complications, was the key determinant of relapse in pediatric brucellosis.

The synchronous occurrence of papillary thyroid carcinoma (PTC) and chronic lymphocytic leukemia (CLL) is rare and poses diagnostic challenges, particularly in distinguishing metastatic thyroid disease from hematological lymphadenopathy. The present report documents the case of a 64-year-old female patient with long-standing CLL who presented with a malignant thyroid nodule accompanied by multiple enlarged cervical lymph nodes. A diagnosis was established through integrated immunohistochemistry, flow cytometry and multimodal imaging. After the diagnosis of synchronous PTC and CLL/SLL was confirmed, the patient underwent a total thyroidectomy with central compartment lymph node dissection. In addition, a focused review of the literature was conducted to contextualize the clinical presentation, diagnostic strategies and management approaches. Treatment and follow-up were guided by a multidisciplinary team. No adverse events occurred during follow-up. At the latest follow-up in November 2025, the patient remained clinically stable, with no evidence of PTC recurrence or CLL progression, and thyroid function test results showed decreased T3, elevated T4 and free T4, mildly elevated thyroid-stimulating hormone, and free T3 within the reference range. The present case highlights the importance of a comprehensive diagnostic work-up and provides practical guidance for the diagnostic and therapeutic management of patients with dual malignancies.

Kikuchi-Fujimoto disease (KFD) is a rare, benign, self-limiting condition characterized by histiocytic necrotizing lymphadenitis that predominantly affects young adults. The clinical presentation often mimics more serious conditions such as tuberculosis and lymphoma, posing a significant diagnostic challenge. We report a case of KFD in a middle-aged adult. A 46-year-old female presented with left posterior cervical lymphadenopathy and fever of 2 weeks' duration. Extensive workup, including tuberculosis screening with GeneXpert, Mantoux test, and culture, was all negative. Ultrasonography and computed tomography revealed multiple necrotic cervical lymph nodes with bilateral involvement. Excisional lymph node biopsy was done, and histopathology revealed patchy areas of necrosis with karyorrhectic debris, proliferation of histiocytes and immunoblasts, and absence of neutrophilic infiltration suggestive of KFD. The patient was given symptomatic treatment and showed complete resolution of symptoms at follow-up. This case emphasizes the importance of considering KFD in the differential diagnosis of cervical lymphadenopathy, particularly when routine investigations for tuberculosis and malignancy are negative. Excisional lymph node biopsy remains the gold standard for diagnosis.

Activated phosphoinositide 3-kinase delta syndrome (APDS) is a rare inborn error of immunity caused by gain-of-function variants in PIK3CD and characterized by recurrent infections, lymphoproliferation, and impaired viral control. We report a 17-year-old male with a heterozygous PIK3CD c.3061G > A (p.E1021K) variant who presented with progressive edema, extensive hypermetabolic lymphadenopathy, splenomegaly, and Epstein-Barr virus (EBV) DNAemia. A core needle biopsy of the right inguinal lymph node demonstrated an immunodeficiency-associated EBV-positive B-cell lymphoproliferative disorder with extensive monotypic plasmacytoid differentiation. Because the biopsy contained limited mature B-cell tissue, the pathological findings favored a polymorphic B-LPD although EBV-positive diffuse large B-cell lymphoma with plasmacytic differentiation could not be excluded. The patient received anti-B-cell-directed therapy and supportive treatment. He was subsequently readmitted with septic shock and acute respiratory distress syndrome. Blood metagenomic next-generation sequencing detected Escherichia coli and Klebsiella pneumoniae, together with antimicrobial-resistance genes including blaNDM. Despite intensive antimicrobial and organ-supportive treatment, the patient remained critically ill and was discharged at his family's request for transfer to a local hospital; his subsequent outcome was unavailable. This case highlights the diagnostic difficulty of classifying EBV-positive B-cell proliferations using limited biopsy tissue in APDS and the competing risks of lymphoproliferative disease and severe infection. Adequate tissue sampling and pathological characterization, close microbiological surveillance, and individualized multidisciplinary management are essential in this setting.

This report presents a within-patient comparison of [18]F-rhPSMA-7.3 and [18]F-PSMA-1007 PET/CT in a 71-year-old man with Gleason score 4 + 3 = 7, pT3bN1 metastatic castration-resistant prostate cancer after robot-assisted radical prostatectomy, multiple androgen-deprivation and androgen receptor-directed treatments, and radiotherapy for para-aortic nodal metastases. The scans showed concordant PSMA-avid cervical-to-mediastinal lymphadenopathy and an ill-defined right lower-lobe pulmonary lesion with a recorded SUVmax > 15, despite distinct physiologic biodistributions. Infection or inflammation remained a relevant differential diagnosis, and the patient declined biopsy. Antibiotics did not improve the CT findings. After enrollment in a clinical trial of systemic therapy, the last available pretreatment prostate-specific antigen (PSA) level of 42.4 ng/mL decreased to 3.1 ng/mL, with marked disease regression. The concordant dual-tracer findings, lack of response to antibiotics, and subsequent radiographic and biochemical response to systemic therapy favored nodal and pulmonary metastases from prostate cancer. However, without histopathologic confirmation, the diagnosis remains presumptive, highlighting the need to integrate PET biodistribution, semiquantitative uptake, anatomic imaging, and longitudinal clinical findings.