Primary cutaneous lymphoma patients seen at a referral dermatological centre in 1 year: A single‐centre observational retrospective cohort study of the diagnoses and staging, comorbidities and associated symptoms, treatment performed and clinical course

IMPORTANCE: Primary cutaneous lymphomas (PCL) are rare diseases, but the indolent course makes their prevalence high. Although there are many treatment options, no hierarchy is recommended. OBJECTIVE: To identify the burden of PCL and describe clinical‐pathologic features; associated comorbidities; analyse treatment approaches in real‐life and the parameters associated with the achievement of complete response (CR). DESIGN, SETTING AND PARTICIPANTS: In this study, all the PCL patients (384 patients) consecutively seen at the Dermatologic Clinic of the University of Turin from January 1, 2019 to December 31, 2019, with follow‐up updated to December 2020, were included. MAIN OUTCOMES AND MEASURES: Subtype of PCL, demographic data, time elapsed between first lesions and diagnosis, associated symptoms, comorbidities, staging at diagnosis, high‐grade transformation, blood involvement, stage progression, therapies used and response were assessed. RESULTS: 247 were cutaneous T‐cell lymphomas (CTCL, 64.3%), 137 cutaneous B‐cell lymphomas (CBCL, 35.7%) and the most frequent subtype was MF (48.4%). 62.3% of CTCL patients showed at least one comorbidity, mainly cardiovascular (28.7%), 20.2% show other not cutaneous neoplasms. The main approaches were skin‐directed therapies (topical steroids 65.6%; phototherapy 50.2%). 39.3% patients achieved a CR during the disease course. Pruritus, the presence of comorbidities and high‐grade transformation were factors associated with failure to achieve CR, whereas stage IA of MF was associated with greater achievement of CR. CONCLUSIONS AND RELEVANCE: The Th2 cytokine related development of pruritus could justify increased resistance to treatment, while the presence of associated comorbidities could reduce treatment options as well as treatment compliance.