Dynamic evaluation of the prognostic value of 18F-FDG PET/CT in extranodal NK/T-cell lymphoma, nasal type

18F-FDG PET/CT in the diagnosis and treatment of atypical extensive skin lesions in extranodal natural killer/T-cell lymphoma, nasal type: a case report

We report a case of a 60-year-old man who developed scattered erythema and papules on his left upper limb without any apparent cause 6 months ago. Initially, the patient underwent evaluations for various dermatological conditions, including eczema and psoriasis, while also being assessed for potential malignancies such as cutaneous lymphoma or sarcoidosis, but no definitive diagnosis was made. Over time, the patient's symptoms progressed, presenting as generalized erythema, papules, localized itching, and pain. A histopathological examination of the lesions diagnosed it as extranodal NK/T-cell lymphoma, nasal type (ENKTCL-NT). Subsequently, the patient was referred for staging via 18F-fluorodeoxyglucose positron emission tomography/computed tomography (18F-FDG PET/CT), which revealed a widespread pattern of metabolically active lesions primarily affecting the skin and subcutaneous tissue of the limbs and buttocks. The patient received sequential treatment with P-GEMOX (gemcitabine, oxaliplatin, and pegaspargase) and underwent clinical examination and follow-up whole-body 18F-FDG PET/CT after six treatment cycles. The post-treatment PET/CT showed no abnormal 18F-FDG uptake in the nasal cavity or skin, confirming clinical complete remission. Our case highlights the significant role of 18F-FDG PET/CT in clinical practice for initial staging and treatment response assessment of ENKTCL-NT.

The role of 18F-FDG PET/CT in diagnosing cardiac infiltration and therapeutic evaluation in extranodal nasal-type NK/T-cell lymphoma: a case report

Extranodal nasal-type NK/T-cell lymphoma is closely associated with Epstein-Barr virus (EBV) infection and primarily involves the nasopharynx. We report a rare case of extranodal nasal-type NK/T-cell lymphoma with widespread lymphomatous infiltration, including cardiac involvement, an exceedingly uncommon manifestation. This case emphasizes the pivotal role of18F-FDG PET/CT in diagnosing and evaluating treatment outcomes in extranodal nasal-type NK/T-cell lymphoma.

Evaluating early response assessment in extranodal natural killer/T-cell lymphoma by analyzing ΔSUVlbm between baseline and interim 18F-FDG PET/CT scans

To determine the optimal variation in SUVlbm via 18F-FDG PET/CT imaging between the baseline and interim stages, and assess early response among patients with extranodal natural killer/T-cell lymphoma (ENKTCL) of 5-DS score ≥ 4, 20 patients after four cycles of chemotherapy were retrospectively enrolled and received re-biopsy targeting PET-positive residual masses. The optimal cutoff value for evaluating early response assessment was 66.75% for ΔSUVlbm%, with the area under curve of 0.985. All patients with a 5-DS score of 4 exhibited negative results upon re-biopsy. During follow-up, the median PFS of patients characterized by ΔSUVlbm% ≥66.75% and <66.75% were unreached and 10 months, respectively. Utilizing ΔSUVlbm% between baseline and interim 18F-FDG PET/CT scans can effectively identify a subset of patients who were visually analyzed as false positives(5-DS ≥ 4), which was confirmed by interim biopsy results, thus serving as a crucial indicator for early assessment of treatment outcomes in patients with ENKTCL.

Peripheral T-cell lymphoma: are all patients high risk?

ABSTRACT

Peripheral T-cell lymphomas (PTCLs) are a heterogeneous group of mature T-cell neoplasms that represent ∼10% of all non-Hodgkin lymphoma. Outcomes for the majority of patients with PTCL are poor, and treatment approaches have been relatively uniform using cyclophosphamide, doxorubicin, vincristine, and prednisone-based therapy. For example, large registry studies consistently demonstrate 5-year overall survival of ∼30% to 40%. However, as our understanding of the biology underpinning the heterogeneity of PTCL improves and as treatments specifically for PTCL are developed, risk stratification has become a more relevant question. Tools including positron emission tomography-computed tomography and minimal residual disease (MRD) monitoring offer the potential for dynamic risk stratification. In this review, we first summarize registry data describing outcomes in the most common subtypes of PTCL: PTCL not otherwise specified, nodal T-follicular helper cell lymphoma including angioimmunoblastic T-cell lymphoma, and anaplastic large cell lymphoma. We describe current clinically based prognostic indices validated for PTCL and highlight emerging tools for prognostication including novel molecular biomarkers, imaging-based metrics, and MRD dynamics.

Appropriate timing to perform an interim 18F-FDG PET/CT in patients with nasal-type extranodal natural killer/T cell lymphoma

Interim 18F-FDG PET/CT (I-PET) has a role in response evaluation and treatment guidance in patients with nasal-type extranodal natural killer/T cell lymphoma (ENKTL). However, there was no agreement on the timing of I-PET performed, after chemotherapy or after chemoradiotherapy. We aimed to find the appropriate timing for I-PET by assessing the prognostic value of I-PET in response evaluation in ENKTL patients. Two hundred and twenty-seven ENKTL patients who had undergone I-PET were retrospectively included. All patients were grouped based on their therapeutic strategy received, chemotherapy or chemoradiotherapy. The Deauville 5-point score (DS) was used to interpret the I-PET images. The hazard ratio (HR) and C-index were used to measure the discriminatory and prognostic capacities of I-PET performed at different times. One hundred and six patients underwent the I-PET after chemotherapy (chemotherapy group), while I-PET was performed after chemoradiotherapy in 121 patients (chemoradiotherapy group). Eighty-seven patients were classified as metabolic remission (DS score of 1-3), while the other 140 were classified as non-metabolic remission (DS score of 4-5) according to the Deauville criteria. There were no significant survival differences between patients in metabolic remission and in non-metabolic remission in either progression-free survival (PFS, p = 0.406) or overall survival (OS, p = 0.350). In the chemotherapy group, patients in metabolic remission had significantly superior PFS than patients in non-metabolic remission (p = 0.012). For OS, a discriminative trend was also found on the survival curve between patients in metabolic remission and in non-metabolic remission (p = 0.082). In the chemoradiotherapy group, there was no significant difference in PFS (P = 0.185) or OS (P = 0.627) between patients in metabolic remission and in non-metabolic remission. I-PET after chemotherapy yields higher discriminative power and has the ability for prognostic prediction in nasal-type ENKTL patients. I-PET after radiochemotherapy has no prognostic value. Thus, the appropriate timing for I-PET is after chemotherapy but before radiotherapy for response evaluation in nasal-type ENKTL patients.

Multimodality imaging evaluation of primary testicular extranodal natural killer/T-cell lymphoma: two case reports

Background

Extranodal natural killer/T-cell lymphoma (ENKTCL) is a distinct pathological entity and accounts for ~10% of T-cell lymphomas. The histological features of ENKTCL include angiodestruction and coagulative necrosis and the association with EBV infection. ENKTCL is typically aggressive and mainly affects the nasal cavity and nasopharyngeal region. However, some patients can present with distant nodal or extranodal involvement such as the Waldeyer ring, gastrointestinal tract, genitourinary organs, lung, thyroid, skin, and testes. Compared to ENKTCL of nasal type, primary testicular ENKTCL is very rare and has a lower age of onset and faster clinical progression, with tumor cell dissemination occurring early in the disease.

Case report

Case 1: A 23-year-old man presented with 1 month of right testicular pain and swelling. Enhancement CT revealed increased density in the right testis, uneven increased enhancement, discontinuity of the local envelope, and multiple trophoblastic vessels in the arterial phase. Testicular ENKTCL was diagnosed by post-operative pathology. The patient underwent a follow-up ¹⁸F-FDG PET/CT imaging 1 month later and found elevated metabolism in the bilateral nasal, left testicular, and right inguinal lymph nodes. Unfortunately, the patient received no further treatment and died 6 months later. Case 2: A 2-year-old male child presented with an enlarged right testicle, MRI showed a mass in the right epididymis and testicular area, which showed low signal on T1WI, high signal on T2WI and DWI, and low signal on ADC. Meanwhile, CT showed soft tissue in the lower lobe of the left lung and multiple high-density nodules of varying sizes in both lungs. Based on the post-operative pathology, the lesion was diagnosed with primary testicular ENKTCL. The pulmonary lesion was diagnosed as hemophagocytic lymphohistiocytosis associated with EBV infection. The child was given SMILE chemotherapy, but pancreatitis was induced during chemotherapy, then he died 5 months later after chemotherapy.

Conclusion

Primary testicular ENKTCL is very rare in clinical practice, typically presenting as a painful testicular mass, which can mimic inflammatory lesions and cause diagnostic challenges. ¹⁸F-FDG PET/CT plays pivotal roles in the diagnosis, staging, evaluation of treatment outcomes and prognosis evaluation in patients with testicular ENKTCL, and it is helpful to assist clinical practice to better formulate individualized treatment plans.

Diagnostic performance and prognostic value of circulating tumor DNA methylation marker in extranodal natural killer/T cell lymphoma

Circulating tumor DNA (ctDNA) carries tumor-specific genetic and epigenetic variations. To identify extranodal natural killer/T cell lymphoma (ENKTL)-specific methylation markers and establish a diagnostic and prognosis prediction model for ENKTL, we describe the ENKTL-specific ctDNA methylation patterns by analyzing the methylation profiles of ENKTL plasma samples. We construct a diagnostic prediction model based on ctDNA methylation markers with both high specificity and sensitivity and close relevance to tumor staging and therapeutic response. Subsequently, we built a prognostic prediction model showing excellent performance, and its predictive accuracy is significantly better than the Ann Arbor staging and prognostic index of natural killer lymphoma (PINK) risk system. Notably, we further establish a PINK-C risk grading system to select individualized treatment for patients with different prognostic risks. In conclusion, these results suggest that ctDNA methylation markers are of great value in diagnosis, monitoring, and prognosis, which might have implications for clinical decision-making of patients with ENKTL.

Extranodal NK/T-Cell Lymphoma With Widespread Cutaneous and Subcutaneous Involvement on 18 F-FDG PET/CT

ABSTRACT

Nasal-type extranodal natural killer/T-cell lymphoma is an aggressive rare type of lymphoma that mostly affects the nasal cavity and adjacent areas. However, some patients can present with distant nodal or extranodal involvement including the Waldeyer ring, gastrointestinal tract, genitourinary organs, lung, thyroid, skin, or adrenal glands. Herein, we present a unique case of extranodal natural killer/T-cell lymphoma with widespread cutaneous and subcutaneous involvement on 18 F-FDG PET/CT.