Gastric follicular lymphoma with mediastinal lymph node dissemination detected by FDG-PET

We read with great interest the article by Higuchi et al., ”Impact of double-balloon endoscopy on the diagnosis of jejunoileal involvement in primary intestinal follicular lymphomas: a case series“ [1]. There is no doubt that, as they concluded, double-balloon endoscopy is useful for evaluating the spread of jejunoileal lesions in patients with gastrointestinal follicular lymphoma (GI-FL). In their report, however, the authors stated that fluorine-18-labeled fluorodeoxyglucose positron emission tomography ([¹⁸F]FDG-PET) was not useful for the clinical assessment of GI-FL. To show the impact of [¹⁸F]FDG-PET on the staging of GI-FL, we report a patient with GI-FL in whom distant dissemination was detected using [¹⁸F]FDG-PET.

An asymptomatic 63-year-old man was referred to our hospital for further examination of a gastric tumor. Physical findings and laboratory data revealed no abnormalities. Esophagogastroduodenoscopy (EGD) showed a submucosal tumor-like lesion with a deep ulcer on the top in the gastric cardia. Biopsy specimens showed aggregated lymphoid follicles with a homogeneous population of small cleaved cells. Immunohistochemical staining was positive for CD20, CD10, and bcl-2. Thus, the patient was diagnosed with grade 1 follicular lymphoma. Colonoscopy and bone marrow aspirate revealed no abnormalities. Although no disseminated lesions other than those in the perigastric lymph nodes were detected by CT of the chest and abdomen, [¹⁸F]FDG-PET revealed a small but obvious accumulation of [¹⁸F]FDG in the mediastinum ([Fig. 1], arrowhead) in addition to those in the stomach ([Fig. 1], arrow).

Fig. 1 Fluoride-18-labeled fluorodeoxyglucose positron emission tomography ([¹⁸F]FDG-PET) in a 63-year-old patient with a gastric tumor reveals a small but obvious accumulation of [¹⁸F]FDG in the mediastinum (arrowhead) as well as the stomach (arrow).

Careful re-evaluation of the chest CT revealed a small mediastinal lymph node ([Fig. 2], lower panel, arrow) in the same position as the [¹⁸F]FDG accumulation ([Fig. 2], upper panel, arrow).

Fig. 2 On careful re-evaluation, the chest CT was found to show a small mediastinal lymph node (lower panel, arrow) in the same position as the [¹⁸F]FDG accumulation (upper panel arrow).

On the basis of these findings, the lymphoma was considered to be stage IV (a gastrointestinal tract lesion with supradiaphragmatic nodal involvement) [2]. The patient was treated with chemotherapy plus rituximab due to the advanced stage of the disease. After six courses of therapy, EGD and CT revealed that the lymphoma had disappeared and [¹⁸F]-FDG-PET showed no abnormal accumulation of [¹⁸F]FDG. There has been no recurrence during the 4-year follow up.

To our knowledge, only two case series reports have investigated the usefulness of [¹⁸F]FDG-PET in GI-FL [1] [3]. In both, the authors suggested that [¹⁸F]FDG-PET was not useful for clinical assessment of GI-FL. It is therefore noteworthy that in the present case we detected a disseminated lesion above the diaphragm by [¹⁸F]FDG-PET that was not detected by CT. Therefore, [¹⁸F]FDG-PET should be considered for the evaluation of extraintestinal involvement in patients with GI-FL, although this modality may not be suitable for evaluating the spread of lesions in the gastrointestinal tract.

Competing interests: None

References

• 1 Higuchi N, Sumida Y, Nakamura K. et al . Impact of double-balloon endoscopy on the diagnosis of jejunoileal involvement in primary intestinal follicular lymphomas: a case series.  Endoscopy. 2009;  41 175-178
• 2 Rohatiner A, d’Amore F, Coiffier B. et al . Report on a workshop convened to discuss the pathological and staging classifications of gastrointestinal tract lymphoma.  Ann Oncol. 1994;  5 397-400
• 3 Hoffmann M, Chott A, Püspök A. et al . 18F-Fluorodeoxyglucose positron emission tomography (18F-FDG-PET) does not visualize follicular lymphoma of the duodenum.  Ann Hematol. 2004;  83 276-278