Anti-interferon-γ Antibody-seropositive Disseminated Nontuberculous Mycobacterial Infection Mimicking POEMS and TAFRO Syndromes

CXCL9 as a Reliable Biomarker for Discriminating Anti-IFN-γ-Autoantibody-Associated Lymphadenopathy that Mimics Lymphoma

The diagnosis of adult-onset immunodeficiency syndrome associated with neutralizing anti-interferon γ autoantibodies (AIGA) presents substantial challenges to clinicians and pathologists due to its nonspecific clinical presentation, absence of routine laboratory tests, and resemblance to certain lymphoma types, notably nodal T follicular helper cell lymphoma, angioimmunoblastic type (nTFHL-AI). Some patients undergo lymphadenectomy for histopathological examination to rule out lymphoma, even in the absence of a preceding clinical suspicion of AIGA. This study aimed to identify reliable methods to prevent misdiagnosis of AIGA in this scenario through a retrospective case-control analysis of clinical and pathological data, along with immune gene transcriptomes using the NanoString nCounter platform, to compare AIGA and nTFHL-AI. The investigation revealed a downregulation of the C-X-C motif chemokine ligand 9 (CXCL9) gene in AIGA, prompting an exploration of its diagnostic utility. Immunohistochemistry (IHC) targeting CXCL9 was performed on lymph node specimens to assess its potential as a diagnostic biomarker. The findings exhibited a significantly lower density of CXCL9-positive cells in AIGA compared to nTFHL-AI, displaying a high diagnostic accuracy of 92.3% sensitivity and 100% specificity. Furthermore, CXCL9 IHC demonstrated its ability to differentiate AIGA from various lymphomas sharing similar characteristics. In conclusion, CXCL9 IHC emerges as a robust biomarker for differentiating AIGA from nTFHL-AI and other similar conditions. This reliable diagnostic approach holds the potential to avert misdiagnosis of AIGA as lymphoma, providing timely and accurate diagnosis.

Thrombocytopenia, anasarca, and renal insufficiency as severe and rare complications of Hodgkin lymphoma: a case report

BACKGROUND

Patients with Hodgkin lymphoma exhibit various clinical presentations. Needle biopsy of the lymph nodes is a minimally invasive procedure and a useful diagnostic method for malignant lymphomas. However, at times it is difficult to differentiate malignant lymphomas from reactive lymph node changes using a small amount of biopsy material.

CASE PRESENTATION

A 77-year-old Japanese man was referred to the emergency department of our hospital owing to high fever and disturbance of consciousness. We diagnosed sepsis due to an acute biliary tract infection because he presented with Charcot's triad-fever, jaundice, and right-sided abdominal pain. However, he did not respond well to antimicrobial therapy and his high fever persisted. Considering the swelling of the right cervical, mediastinal, and intraperitoneal lymph nodes and splenomegaly detected on computed tomography, a differential diagnosis of malignant lymphoma was needed. Hence, we performed a needle biopsy of the right cervical lymph node; however, the amount of sample obtained was insufficient in establishing a definitive diagnosis of malignant lymphoma. Furthermore, during hospitalization, the patient developed thrombocytopenia, anasarca, and renal insufficiency. These symptoms seemed to be the typical signs of the thrombocytopenia, anasarca, fever, reticulin fibrosis or renal insufficiency, and organomegaly syndrome. Next, an external incisional mass biopsy of the right cervical lymph node was performed, which helped identify Hodgkin and Reed-Sternberg cells. Collectively, we established a definitive diagnosis of Hodgkin lymphoma with lymphoma-associated hemophagocytic syndrome.

CONCLUSIONS

This case highlights the importance of performing an external incisional mass biopsy of the lymph nodes for the early diagnosis and treatment, if malignant lymphoma is strongly suspected.