Incidence and ten-year follow-up of primary cutaneous lymphomas: a single-centre cohort study

Primary cutaneous lymphomas (PCLs) are a rare group of extranodal non-Hodgkin lymphomas, and epidemiological data in Mediterranean countries are scarce.

To investigate the incidence and characteristics of PCL in a single tertiary referral centre in Italy.

A total of 141 PCL patients, seen over a 10-year follow-up period, were investigated.

Incidence rate of PCL was 0.8 cases/100,000 person years. T-cell lymphoma represented 78.7% of all cases, the majority being early mycosis fungoides (MF) (64%; median age: 66 years), followed by lymphomatoid papulosis (LyP) (19%; median: age 48 years), and others (median age: 72 years), including eight cases of anaplastic large CD30+ T-cell lymphoma, four CD4+ small-medium pleomorphic T-cell lymphoproliferative disorder, four Sézary syndrome, one subcutaneous panniculitis-like T-cell lymphoma, one extranodal NK/T-cell lymphoma nasal-type, and one angioimmunoblastic T-cell lymphoma. B-cell lymphoma accounted for 21.3% of PCL, with 20 cases of cutaneous follicular centre B-cell (median age: 63 years), four primary cutaneous marginal zone, three primary cutaneous diffuse large B-cell, and three leg-type lymphoma. Complete remission within the first year after diagnosis occurred in 70.4% of MF, 61.9% of LyP, 78.9% of other T-cell lymphoma, and 93.1% of B-cell lymphoma cases. Based on a Cox proportional hazard regression model, age, gender, stage, and lactate dehydrogenase and β2-microglobulin blood levels did not predict clinical remission of MF or LyP.

The incidence and characteristics of PCL in Italy are similar to those in other European countries. PCLs may be diagnosed at very early stages with good prognosis.