Israel Medical Association Journal

Background: Whole-body integrated positron emission tomography / contrast-enhanced computed tomography (PET/CT) scan is increasingly used in cutaneous lymphomas. However, the value of PET/CT in the detection of cutaneous lesions in primary cutaneous B-cell lymphoma (PCBCL) has barely been investigated.

Objectives: To investigate the diagnostic accuracy of PET/CT in tracking cutaneous involvement in PCBCL.

Methods: A retrospective study was conducted on 35 consecutive patients diagnosed with cutaneous B-cell lymphoma according to the World Health Organization classification who were evaluated with PET/CT as the initial staging procedure before treatment.

Results: Thirty-five patients met the study criteria. In two patients extracutaneous disease was detected by PET/CT and CT and confirmed by biopsy. Of the 33 patients with PCBCL, 26 (79%) had small cell PCBCL (18 marginal-zone, 8 follicle-center lymphoma) and 7 (21%) had large cell PCBCL (3 follicle-center, 3 leg-type, 1 indeterminate). PET/CT detected skin lesions in 3 of 26 patients (12%) with small-cell PCBCL as compared to 6 of 7 patients with large-cell PCBLC (86%), a 7.4-fold detection risk (95% confidence interval, 2.4–22, P = 0.004). The PET-positive subgroup was characterized by larger lesion size (P < 0.001) and a higher Ki-67 proliferation index (P < 0.001).

Conclusions: The sensitivity of PET/CT for detecting cutaneous involvement of lymphomas is low for small-cell PCBCL but high for large-cell types, and thus may facilitate therapeutic strategies.

Background: Pulmonary infiltrates (PIs) detected in patients with non-Hodgkin lymphoma (NHL) may present a diagnostic challenge due to their wide differential diagnosis, including infection, pulmonary lymphoma and immunochemotherapy-associated pulmonary toxicity.

Objectives: To characterize therapy-associated PIs by positron emission tomography/computed tomography (PET/CT) imaging.

Methods: We conducted a historical analysis of fluorodeoxyglucose-PET/CT (¹⁸F-FDG-PET/CT) PIs in NHL patients treated with combined immunochemotherapy including rituximab. Incidence of PIs, radiological features, patients’ characteristics, underlying NHL type, rituximab/chemotherapy dosing schedules, and symptoms were recorded. Therapy-associated PIs were defined as new or worsening PIs appearing after treatment onset, without evidence of active pulmonary lymphoma or infection.

Results: Among 80 patients who met the pre-specified criteria, therapy-associated PIs were identified in 17 (21%), 6 of whom had accompanying symptoms. Increased FDG uptake was observed in nine, and PI resolution in six. The incidence of PIs was higher in females and in patients with aggressive lymphoma, at advanced stages, and in those who had received treatment consisting of a combination of rituximab, cyclophosphamide, doxorubicin, vincristine, and prednisolone every 14 days (R-CHOP-14).

Conclusions: This characterization of therapy-associated PIs may support the clinician managing NHL patients. Further prospective studies are needed to establish the role of each therapeutic component and the natural history of this phenomenon.