Nodal status of malignant lymphoma in pelvic and retroperitoneal lymphatic pathways: PET/CT

Role of Total Body PET/CT in Inflammatory Disorders

Inflammatory disorders historically have been difficult to monitor with conventional PET imaging due to limitations including radiation exposure, lack of validated imaging biomarkers, low spatial resolution, and long acquisition durations. However, the recent development of long-axial field-of-view (LAFOV) PET/CT scanners may allow utilization of novel noninvasive biomarkers to diagnose, predict outcomes, and monitor therapeutic response of inflammatory conditions. LAFOV PET scanners can image most of the human body (if not the entire body) simultaneously in one bed position, with improved signal collection efficiency compared to conventional PET scanners. This allows for imaging with shorter acquisition durations, decreased injected radiotracer dose, prolonged uptake times, or a combination of any of these. In addition, LAFOV PET scanners enable whole-body dynamic imaging. Altogether, these intrinsically superior capabilities in assessing both local and systemic diseases, have allowed these scanners to make increasingly significant contributions to the assessment of inflammatory conditions. This review aims to further explore the role and benefits of LAFOV scanners for imaging various inflammatory conditions while addressing future developments and challenges faced by this technology.

Limited benefit of additional contrast-enhanced CT to end-of-treatment PET/CT evaluation in patients with follicular lymphoma

Despite follicular lymphoma (FL) is frequently characterized by a moderate increase of glucose metabolism, PET/CT examinations provides valuable information for staging and response assessment of the disease. The aim of the study was to assess and compare the diagnostic performance of PET/ldCT and PET/ceCT, respectively, in evaluating FL patients at the end of treatment. Fifty FL consecutive patients who underwent end-of-therapy PET/CT with both ldCT and ceCT were analyzed. Two blinded observers independently assessed PET/ldCT and PET/ceCT applying the Deauville score (DS) and Lugano classification criteria. PET imaging obtained after the end-of-treatment (EoT) was classified as showing PET and ce-CT matched response (concordant imaging group, CIG) or PET and ce-CT unmatched response (discordant imaging group, DIG). Relapse rate and Event-Free Survival (EFS) were compared between CIG and DIG patients. Overall, no differences in metabolic response classification were observed between PET/ldCT and PET/ceCT. In 13 (26%) patients PET/ceCT identified additional FDG-negative nodal lesions in mesenteric, retroperitoneal and iliac regions. However, in all cases, final DS remained unchanged and the additional results did not modify the following therapeutic decision. Among patients, who obtained complete metabolic response a comparable rate of relapse was registered in DIG 3/13 (23%) and CIG subgroups 5/20 (25%) [p = 0.899]. In all 3 DIG cohort patients who relapsed the recurrent disease involved also, but not exclusively, PET negative lymph nodes detected by ceCT. In overall population metabolic response defined by PET/ldCT predicted EFS [76% (group of patients with metabolic response) vs 35% (group of patients with residual disease), p = 0.0013] significantly better than ceCT-Based response assessment [75% (group of patients with complete response) vs 53% (group of patients with residual disease), p = 0.06]. Our study demonstrates a negligible diagnostic and predictive value of ceCT performed in addition to standard ¹⁸FDG PET/ldCT for EoT response evaluation in FLs. PET/ldCT should be performed as first-line imaging procedure, also in patients with prevalent abdominal and pelvic involvement, limiting the acquisition of ceCT in selected cases. This tailored approach would contribute to avoid useless radiation exposure and preserve renal function of patients.

Non-adrenal tumors of the adrenal area; what are the pitfalls?

Discovery of an adrenal mass is nowadays a frequent situation. While adrenal tumors can cause a variety of symptoms, more often than not they are diagnosed incidentally on imaging exams such as CT-scan or MRI performed for another purpose. However, any retroperitoneal supra-renal mass can have an extra-adrenal origin. Indeed, operated non-adrenal masses initially but wrongly diagnosed as an adrenal disease represent about 3.5% of adrenalectomies. These differential diagnoses principally include retroperitoneal tumors that are malignant in two thirds of cases (lymphomas, sarcomas, neurogenic or germinal tumors), and more rarely vascular anomalies or congenital malformations, which are most frequently left-sided due to the wide variety of anatomical structures surrounding the left adrenal gland. Several lesions can originate from the adrenal gland or be located near the gland (paraganglioma, ganglioneuroma). Even though unilateral adrenalectomy is associated with low morbidity, ignorance of these differential diagnoses can cause ill-adapted management; overly conservative surgery in case of sarcoma is one example. Some of these lesions have characteristic clinical or imaging features (cystic lymphangioma, angiomyolipoma…). In other cases, assessment of hormonal secretion is required and additional exams (MRI, percutaneous biopsy, PET-scan with 18-Fluorodeoxyglucose) can correct an erroneous diagnosis. The above diagnostic approach allows appropriate management (with or without surgery). The purpose of this review was to highlight the main differential diagnoses of adrenal masses, to describe their characteristics, and to discuss their therapeutic management.

Prognostic impact of abdominal lymph node involvement in diffuse large B-cell lymphoma

Objective

The prognostic value of site of nodal involvement in diffuse large B‐cell lymphomas (DLBCL) is mainly unknown. We aimed to determine the prognostic significance of nodal abdominal involvement in relation to tumour cell markers and clinical characteristics of 249 DLBCL patients in a retrospective single‐centre study.

Methods

Contrast‐enhanced computed tomography (CT) of the abdomen and thorax revealed pathologically enlarged abdominal lymph nodes in 156 patients, while in 93 patients there were no pathologically enlarged lymph nodes in the abdomen. In 81 cases, the diagnosis of DLBCL was verified by histopathological biopsy obtained from abdominal lymph node.

Results

Patients with abdominal nodal disease had inferior lymphoma‐specific survival (P = .04) and presented with higher age‐adjusted IPI (P < .001), lactate dehydrogenase (P < .001) and more often advanced stage (P < .001), bulky disease (P < .001), B symptoms (P < .001), and double expression of MYC and BCL2 (P = .02) compared to patients without nodal abdominal involvement, but less often extranodal involvement (P < .02). The worst outcome was observed in those where the abdominal nodal involvement was verified by histopathological biopsy.

Conclusion

Diffuse large B‐cell lymphomas patients with abdominal nodal disease had inferior outcome and more aggressive behaviour, reflected both in clinical and biological characteristics.

A Primary Retroperitoneal Diffuse Large B-Cell Lymphoma: A Challenging Diagnosis

Although quite rare, retroperitoneum can harbour malignant limphomas. On the grounds that the anatomical location is uncommon and the symptoms are scarce, the diagnosis is usually late and challenging. Imaging methods such as magnetic resonance imaging, computed tomography (CT) and positron emission tomography-computed tomography (PET-CT), can characterize and locate the tumor while endoscopic ultrasound fine needle aspiration (EUS-FNA) may provide pathological confirmation. We present the clinical case of a fifty-five-year-old female that is admitted to our hospital with epigastric discomfort, nausea and vomiting. CT showed a homogenously enhancing mass lesion that encased the pancreas, in contact with the portal vein, inferior vena cava, invading splenomesenteric confluence. To investigate further, EUS-FNA was decided and it revealed lymphocyte proliferation suggestive for the diagnosis of lymphoma. Hereinafter, surgical intervention was performed and immunohistochemical analysis and sub classification of lymphoma was obtained. The final diagnosis was non-Hodgkin lymphoma, Diffuse Large B-Cell Lymphoma (DLBCL). Poly-chemotherapy with R-CHOP was initiated. At the end of the treatment fluorodeoxyglucose positron emission tomography (FDG-PET) was performed and no pathological findings were found. A brief review of literature is also provided.

[Retroperitoneal tumors]

BACKGROUND

Retroperitoneal tumors are rare malignancies. The retroperitoneum can host a wide spectrum of pathologies including primary or metastatic lesions.

OBJECTIVE

Treatment of retroperitoneal tumors is often associated with several challenges because of their relative late presentation and anatomic location.

MATERIALS AND METHODS

Because of various pathologies, a detailed case history, laboratory investigation and ultrasound should be performed. Radiologic examinations remain a major component in the diagnosis. In addition to computed tomography, magnetic resonance imaging and positron emission tomography are used. Although radiologic findings are often unspecific, there are often typical findings such as dissemination, margins, vascularization and tumor texture which contribute to the differential diagnosis even before making a definitive diagnosis. Due to the complexity of primary retroperitoneal tumors, which require different treatments depending on the final diagnosis, the treatment approach should be determined in a multidisciplinary tumor conference prior to histological confirmation and initiation of treatment.

CONCLUSION

To ensure the best potential curative treatment modality for retroperitoneal tumors, treatment is best performed in high-volume centers by a multidisciplinary team.

¹⁸F-FDG-PET/CT findings of retroperitoneal tumors: a pictorial essay

A variety of different tumors can arise from any of the tissues present in the retroperitoneum, and they exhibit a wide range of pathologic types. Although computed tomography (CT) and magnetic resonance imaging (MRI) can demonstrate important characteristics of these tumors, diagnosis is often challenging for radiologists. The purpose of this pictorial essay is to review (18)F-fluorodeoxyglucose positron emission tomography/CT (FDG-PET/CT) features of different kinds of benign and malignant retroperitoneal tumors in comparison with CT or MRI findings alone and to become familiar with the wide variety of imaging characteristics.

18F-fluorodeoxyglucose positron emission tomography/computed tomography findings in mucosa-associated lymphoid tissue lymphoma of the larynx: a case report and literature review

Laryngeal mucosa-associated lymphoid tissue (MALT) lymphoma is rare, with only 25 cases reported in the literature. This report presents a case of laryngeal MALT lymphoma in a 35-year-old female with a 6-year history of progressively worsening hoarseness. MALT lymphoma was diagnosed based on biopsy and immunohistochemical analysis. The patient received two cycles of cyclophosphamide + epirubicin + vincristine + prednisone (CHOP) chemo therapy, which was ineffective. (18)F-fluorodeoxyglucose ((18)F-FDG) positron emission tomography/computed tomography (PET/CT) showed (18)F-FDG accumulation in the larynx only and identified stage IE lymphoma. CHOP chemotherapy was terminated and the patient was treated with radiotherapy. After 3 months (total radiation dose 27 Gy), (18)F-FDG PET/CT scan showed that the laryngeal lesion was in complete remission. A review of the literature on the MEDLINE(®)/PubMed(®) databases regarding laryngeal MALT lymphoma and the use of PET/CT found that radiotherapy is the first-line treatment for stage I and II MALT lymphoma.