Should we be imaging lymph nodes at initial diagnosis of cutaneous early-stage mycosis fungoides? Results from the PROCLIPI international Study

Background: Early-stage mycosis fungoides (MF) includes patients with dermatopathic lymph nodes (LNs) or early lymphomatous LN involvement. There is lack of unanimity among current guidelines regarding the indications for initial staging imaging in early cutaneous presentation of MF in the absence of enlarged palpable LNs.

Methods: Review of clinicopathologically confirmed newly diagnosed patients with cutaneous patch/plaque (T1/T2) MF from PROspective International Cutaneous Lymphoma Prognostic Index (PROCLIPI) data.

Results: PROCLIPI enrolled 375 patients with T1/T2 MF: 304 classical-MF and 71 folliculotropic-MF. Imaging was performed in 169 patients (45%; 83=CT, 18=PET/CT, 68=U/S); only 9 (5%) had palpable enlarged (≥15mm) LNs, with an over-representation of plaques, irrespective of the 10% body-surface-area cutoff which distinguishes T1 from T2. Folliculotropic-MF was not more frequently imaged than classical-MF. Radiologically enlarged LNs (≥15mm) were detected in 30 patients (18%); only 7 had clinical lymphadenopathy. On multivariate analysis, plaque presentation was the sole parameter significantly associated with radiologically enlarged LNs. Imaging of only clinically enlarged LNs upstaged 4% of patients (7/169) to at least IIA, whereas non-selective imaging upstaged another 14% (24/169). LN biopsy, performed in 8/30, identified N3 (extensive lymphomatous involvement) in 2, and N1 (dermatopathic changes) in 6.

Conclusion: Physical examination was a poor determinant of LN enlargement/involvement. Presence of plaques was associated with significant increase in identification of enlarged/involved LN in patients with cutaneous early-stage MF, which may be important when deciding who to image. Imaging increases detection rate of stage-IIA, and identifies rare cases of extensive lymphomatous nodes, upstaging them to advanced-stage IVA2.