Diagnostic role of 18F-fluorodeoxyglucose positron emission tomography for follicular lymphoma with gastrointestinal involvement

Abstract

AIM:To investigate the capacity for 18F-fluorodeoxyglucose (18F-FDG) positron emission tomography (PET) to evaluate patients with gastrointestinal lesions of follicular lymphoma. METHODS:This retrospective case series consisted of 41 patients with follicular lymphoma and gastrointestinal involvement who underwent 18F-FDG-PET and endoscopic evaluations at ten different institutions between November 1996 and October 2011. Data for endoscopic, radiological, and biological examinations performed were retrospectively reviewed from clinical records. A semi-quantitative analysis of 18F-FDG uptake was performed for each involved area by calculating the maximum standardized uptake value (SUVmax). Based on the positivity of 18F-FDG uptake in the gastrointestinal lesions analyzed, patients were subdivided into two groups. To identify potential predictive factors for 18F-FDG positivity, these two groups were compared with respect to gender, age at diagnosis of lymphoma, histopathological grade, pattern of follicular dendritic cells, mitotic rate, clinical stage, soluble interleukin-2 receptor levels detected by 18F-FDG-PET, lactate dehydrogenase (LDH) levels, hemoglobin levels, bone marrow involvement, detectability of gastrointestinal lesions by computed tomography (CT) scanning, and follicular lymphoma international prognostic index (FLIPI) risk. ORIGINAL ARTICLE RESULTS:Involvement of follicular lymphoma in the stomach, duodenum, jejunum, ileum, cecum, colon, and rectum was identified in 1, 34, 6, 3, 2, 3, and 6 patients, respectively. No patient had esophageal involvement. In total, 19/41 (46.3%) patients exhibited true-positive 18F-FDG uptake in the lesions present in their gastrointestinal tract. In contrast, false-negative 18F-FDG uptake was detected in 24 patients (58.5%), while false-positive 18F-FDG uptake was detected in 5 patients (12.2%). In the former case, 2/19 patients had both 18F-FDG-positive lesions and 18F-FDGnegative lesions in the gastrointestinal tract. In patients with 18F-FDG avidity, the SUVmax value of the involved gastrointestinal tract ranged from 2.6 to 17.4 (median: 4.7). For the 18F-FDG-negative (n = 22) and -positive (n = 19) groups, there were no differences in the male to female ratios (10/12 vs 4/15, P = 0.186), patient age (63.6 ± 2.4 years vs 60.1 ± 2.6 years, P = 0.323), presence of histopathological grade 1 vs 2 (20/2 and 17/2, P = 1.000), follicular dendritic cell pattern (duodenal/nodal: 13/5 vs 10/3, P = 1.000), mitotic rate (low/ partly high, 14/1 vs 10/3, P = 0.311), clinical stage according to the Ann Arbor system (stages ⅠE and ⅡE/ other, 15/7 vs 15/4, P = 0.499), clinical stage according to the Lugano system (stages Ⅰ and Ⅱ-1/other, 14/8 vs 14/5, P = 0.489), soluble interleukin-2 receptor levels (495 ± 78 vs 402 ± 83, P = 0.884), LDH levels (188 ± 7 vs 183 ± 8, P = 0.749), hemoglobin levels (13.5 ± 0.3 vs 12.8 ± 0.4, P = 0.197), bone marrow involvement (positive/negative, 1/8 vs 1/10, P = 1.000), detectability by CT scanning (positive/negative, 1/16 vs 4/13, P = 0.335...

From the Radiologic Pathology Archives: Gastrointestinal Lymphoma: Radiologic and Pathologic Findings

“…The frequent absence of CT findings may be explained by the small size of the lesions. FDG PET also is not a reliable imaging tool, with a sensitivity of 46% for detecting GI follicular lymphoma (54). This high false-negative rate is likely related to the small size of the GI lesions, as well as the lower avidity of GI follicular lymphoma at FDG PET compared with more aggressive forms of lymphoma (54).…”

“…Imaging Features.-GI follicular lymphomas are manifested at barium studies and CT by multiple small-bowel nodules of varying size (53). In one retrospective study, however, Iwamuro (54) found that only 15% of patients with GI involvement by follicular lymphoma had abnormal GI findings at CT, with a thickened bowel wall in all cases (Fig 10). The frequent absence of CT findings may be explained by the small size of the lesions.…”

Debate on the value of end-of-treatment FDG-PET response evaluation in follicular lymphoma

“…As a result, response to therapy of lymphomatous deposits lodging in the bone marrow cannot be assessed using FDG-PET. The same applies to the gastrointestinal tract, since studies have shown that FDG-avidity is absent in large proportions of patients with biopsy-proven intestinal involvement [19,20].…”

Colorectal Manifestation of Follicular Lymphoma

“…Patients with grade 3 follicular lymphoma were excluded from this study because these cases are typically managed as cases of diffuse large B-cell lymphoma (1). A subset of the 12 patients examined herein were also subjects of our previous studies (4,(7)(8)(9)(10)(11)(12)(13)(14)(15)(16).…”