A Retrospective Study of the Probability of the Evolution of Parapsoriasis en Plaques into Mycosis Fungoides

Abstract

Parapsoriasis en plaque has been suggested to be an early manifestation of mycosis fungoides (cutaneous T-cell lymphoma). We explored the disease course of patients with small plaque or large plaque parapsoriasis in a 26-year retrospective cohort analysis of 105 parapsoriasis patients, who were clinically and histopathologically followed up in Helsinki and Tampere University Hospitals. Eventual later cancers of these patients were verified from the Finnish Cancer Registry. In the small plaque parapsoriasis group, 7 patients (10%) and in the large plaque parapsoriasis group 12 patients (35%), developed histologically confirmed mycosis fungoides during a median of 10 and 6 years, respectively. No significant differences were found regarding the risk of developing mycosis fungoides or the tendency to remission in patients treated with or without phototherapy. Our results show that not only large plaque parapsoriasis, but also small plaque parapsoriasis, as currently defined in textbooks, can progress to mycosis fungoides. The benefits of phototherapy are equivocal in parapsoriasis treatment as far as progression to cancer is concerned.

Molecular cytogenetics in the study of cutaneous T-cell lymphomas (CTCL)

“…A consistent viral, environmental, or occupational causative factor or hereditary mutation has not been found (Ranki et al, 1990;Väkevä et al, 2000Väkevä et al, , 2005Burg et al, 2001;Girardi, 2004 review;Morozov et al, 2005;Pawlaczyk et al, 2005). Early conventional cytogenetic studies showed a large repertoire of chromosomal abnormalities in CTCL, both clonal and non-clonal, but no specific abnormality (Whang-Peng et al, 1982).…”

“…parapsoriasis en plaques, considered by some experts as already CTCL. In our own clinical material, 10% of small plaque parapsoriasis (SPP) and 35% of large plaque parapsoriasis (LPP) cases developed to MF during a mean follow-up time of nine years (Väkevä et al, 2005). In advanced CTCL, malignant cells are found in lymph nodes, viscera and blood.…”

Ichthyosiform large plaque parapsoriasis: Report of a rare entity

“…[6] LPP tends to present in middle aged people with peak incidence in fifth decade with slight male preponderance. [2] Our patient had an early age of onset in the fourth decade.…”

Systematic review of cases of cutaneous T-cell lymphoma transformation in pityriasis lichenoides and small plaque parapsoriasis

“…In the cases we reviewed, there was a long latency between initial presentation and CTCL diagnosis. Although SPP often persists for many years, the average duration of PLC when it follows a self‐resolving course is 1·5–31 months . Many patients developed morphological changes within plaques, including induration or nodules, poikilodermatous changes and atrophic areas.…”