Frequency and prognosis of associated malignancies in 504 patients with lymphomatoid papulosis.

BACKGROUND: Lymphomatoid papulosis (LyP) can be associated with other haematological malignancies (HM), but reported percentages vary from 20% to over 50%. OBJECTIVE: To evaluate the frequency and prognostic significance of associated HM and non-HM in LyP patients. METHODS: In this multicentre cohort study, the complete Dutch LyP population was included from the Dutch Cutaneous Lymphoma Registry between 1985 and 2018. Clinical and histopathological information was retrieved from every individual patient. RESULTS: After a median follow-up of 120 months (range, 6-585), an associated HM was observed in 78/504 (15.5%) patients. Most common associated HM were mycosis fungoides (MF; n = 31) and anaplastic large-cell lymphoma (ALCL; n = 29), while 19 patients had another HM of B-cell (n = 14) or myeloid origin (n = 5). Even after a 25-year follow-up period, percentages of associated HM did not exceed 20%. Thirty-nine of 465 patients (8.4%) without a prior or concurrent associated HM developed an associated HM during follow-up, after a median of 68 months (range of 3-286 months). Nine of 78 patients died of associated HM, including 6/22 patients developing extracutaneous ALCL, while all patients with associated MF or skin-limited ALCL had an excellent prognosis. Compared with the general population, LyP patients showed an increased risk (relative risk, 2.8; 95% confidence intervals, 2.4-3.3) for non-HM, in particular cutaneous squamous cell carcinoma, melanoma and intestinal/lung/bladder cancer. CONCLUSIONS: An associated HM was reported in 15.5% of the LyP patients, particularly MF and ALCL. Although the frequency of associated HM is lower than suggested and the prognosis of most patients with associated HM is excellent, a small subgroup will develop aggressive disease, in particular extracutaneous ALCL. Furthermore, LyP patients have a higher risk of developing other malignancies. Clinicians should be aware of these risks, and LyP patients require close monitoring.

Evaluation of treatment results in multifocal primary cutaneous anaplastic large cell lymphoma: report of the Dutch Cutaneous Lymphoma Group.

BACKGROUND: There is no consensus on the treatment of multifocal primary cutaneous anaplastic large cell lymphoma (C-ALCL). Radiotherapy (RT) and methotrexate (MTX) are the current treatment options, but their efficacy is unknown. Recently, targeted therapies showed promising results in C-ALCL, and may therefore be an attractive first choice of treatment. OBJECTIVES: To assess the efficacy of conventional treatment strategies for patients with multifocal C-ALCL, and to define which patients may require novel targeted therapies. METHODS: In this multicentre study, treatment was evaluated in patients initially presenting (n = 24) or relapsing with multifocal C-ALCL (n = 17; 23 relapses). Distinction was made between patients with five or less lesions (n = 36) and more than five lesions (n = 11). RESULTS: Treatments most commonly used were RT (n = 21), systemic chemotherapy (n = 9) and low-dose MTX (n = 7) with complete response rates of 100%, 78% and 43%, respectively, and an overall response rate of 100%, 100% and 57%, respectively. Four patients showed complete spontaneous regression. In total, 16 of 24 patients (67%) first presenting with multifocal C-ALCL relapsed, including all five patients initially treated with CHOP (cyclophosphamide, hydroxydaunorubicin, oncovin and prednisone). Compared with patients presenting with two to five skin lesions, patients presenting with more than five lesions had a higher chance of developing extracutaneous relapse (56% vs. 20%) and more often died of lymphoma (44% vs. 7%). CONCLUSIONS: Patients with five or less lesions should be treated with low-dose RT (2 × 4 Gy). Maintenance low-dose MTX (20 mg weekly) is a suitable option in patients with more than five lesions. Targeted therapies may be considered in rare patients who are refractory to MTX or patients developing extracutaneous disease.