P216 Real-world outcomes of primary cutaneous CD4+ small/medium T-cell lymphoproliferative disorder in a UK supraregional cutaneous lymphoma centre

Abstract

Primary cutaneous CD4+ small/medium T-cell lymphoproliferative disorder (PCSM-TCLPD) was defined in the 2018 WHO–EORTC classification of primary cutaneous lymphomas, replacing the term ‘lymphoma’ to reflect its indolent behaviour and uncertain malignant potential. Despite reclassification, optimal follow-up protocols remain unclear. This study is a retrospective analysis of all patients diagnosed with PCSM-TCLPD at a UK supraregional cutaneous lymphoma centre between September 2018 and November 2025. Forty patients were identified, with a male-to-female ratio of 1 : 1 and a median age at diagnosis of 57.0 years (range 4–79). Most lesions occurred on the head and neck (55%). Morphologically, 80% were solitary papules or nodules, and 15% were plaques. Imaging (computed tomography or positron emission tomography–computed tomography) was performed in 38 of 40 patients, with no PCSM-TCLPD-related systemic disease detected. Euroclonality next-generation sequencing was conducted on six patient biopsies, identifying diagnostic clonal populations in 50% (n = 3). Of the clonal variants identified, TRBD1 and TRBD2 gene rearrangements were seen in all cases. Initial treatment included excision (n = 22), radiotherapy (n = 10), excision followed by radiotherapy (n = 4), spontaneous resolution (n = 3) and topical clobetasol (n = 1). The overall recurrence rate was 15% (6 of 40). The median time to recurrence was 36 months (range 6–132). Five patients experienced a single recurrence, and one patient had three, accounting for eight recurrence episodes. Recurrences were managed with radiotherapy (n = 6), spontaneous resolution (n = 1) or treatment at another centre (n = 1). Of the six patients with recurrence, one developed stage IV peripheral T-cell lymphoma, 14 years after PCSM-TCLPD diagnosis. Follow-up was variable, typically annual, with earlier review available on request (n = 22). Seven patients (18%) were discharged after a median of 5 years. There were no disease-related deaths. Secondary malignancies were identified in three patients (peripheral T-cell lymphoma, breast cancer, and pancreatic gastrointestinal stromal tumour). PCSM-TCLPD demonstrates a good prognosis with a low recurrence rate and rare progression. These findings suggest that computed tomography imaging and prolonged intensive follow-up may not be necessary for most patients.