Patients with Lymphomatoid papulosis (LyP) showed a much lower rate of associated hematologic malignancies (HMs) than shown in earlier studies, data published in the Journal of the European Academy of Dermatology and Venerology suggest. Compared with recently reported rates ranging from 20% to as high as 50%, the current study found an association with HM in only 15.5% of LyP cases.
The investigators collected histopathological and clinical data on all 504 patients entered into the Dutch Cutaneous Lymphoma Registry from 1985 to 2018. A total of 78 patients (15.5% of the cohort) demonstrated that HMs were associated with their disease at a median follow-up of 120 months, which did not increase beyond 20% even when follow-up was extended out to 25 years. Mycosis fungoides (MF) was the most common type of HM, diagnosed in 31 patients, followed by anaplastic large cell lymphoma (ALCL) in 29 patients and B-cell or myeloid malignancies in 14 and 5 patients, respectively.
The prognosis for most of the patients who developed HMs was excellent, although they were found to be at higher risk for the development for various forms of non-HMs, such as cutaneous squamous cell carcinoma, melanoma, and intestinal, lung, and bladder cancers, when compared with the general population.
A subgroup of the patients with HMs did experience a more aggressively malignant disease course. Nine of the 78 patients with LyP with HMs consequently died from cancer. Six of 22 patients who developed extracutaneous disease died of associated ALCL, although those who developed the skin-limited form of ALCL survived with excellent prognoses. The investigators highlighted the fact that none of the 7 patients with LyP preceded by systemic localized HM died from lymphoma. Four of 5 patients who developed extracutaneous ALCL accompanied by a single persistent tumor all responded very well to combination chemotherapy to achieve complete and sustained remission. The fifth patient had a spontaneous regression of all skin and nodal lesions that also produced a sustained remission.
The researchers suggested several potential reasons for the significantly lower rate of LyP-associated malignancies observed in their study, including a selection bias to the cohort based on the definition of HM, which was not provided by previous studies.
The majority of patients had good outcomes, and serious consequences to LyP were rare. Risk for developing any form of CTCL in any patient without a prior or concurrent MF or ALCL at the time of LyP diagnosis was only 7%, and risk for extracutaneous localizations was only 3%.
Melchers RC, Willemze R, Bekkenk MW, et al. Frequency and prognosis of associated malignancies in 504 patients with lymphomatoid papulosis [published online November 12, 2019]. J Eur Acad Dermatol Venereol. doi:10.1111/jdv.16065