Paediatric cutaneous lymphomas including rare subtypes: A 40-year experience at a tertiary referral centre

Abstract

Background: Primary cutaneous lymphomas are neoplasms of the immune system with a distinct tropism for the skin and an absence of extracutaneous manifestations at the time of diagnosis. Studies focusing on cutaneous lymphomas in children and adolescents remain scarce and often do not encompass the rare subtypes.

Objectives: To address this knowledge gap by describing the clinical, histological and molecular characteristics of a large group of paediatric patients affected by primary cutaneous lymphoma. We also provided the Paediatric Primary Cutaneous Lymphoma Atlas that illustrates the clinicopathological spectrum of observed presentations, in the hope of supporting other physicians in the diagnostic process.

Methods: Retrospective chart review of paediatric patients diagnosed with primary cutaneous lymphomas between 1980 and 2022 at the Paediatric Dermatology Unit of Fondazione IRCCS Ca' Granda Ospedale Maggiore Policlinico, Milan.

Results: A total of 101 patients (58 males, 43 females) met the inclusion criteria. The most common subtypes were lymphomatoid papulosis (n = 48) and mycosis fungoides (n = 31). These were followed by primary cutaneous CD4⁺ small/medium T-cell lymphoproliferative disorders (n = 7), primary cutaneous anaplastic large-cell lymphomas (n = 5), primary cutaneous marginal zone B-cell lymphomas (n = 3), primary cutaneous follicle centre lymphomas (n = 2), subcutaneous panniculitis-like T-cell lymphomas (n = 2), primary cutaneous peripheral T-cell lymphoma not otherwise specified (n = 1), primary cutaneous precursor B-lymphoblastic lymphoma (n = 1) and Sézary syndrome (n = 1). Clinical follow-up data covering a median of 70.8 months (range 1-324) were available for 74 patients, of whom three died due to cutaneous lymphoma.

Conclusions: Our findings shed light on the peculiar aspects and long-term outcomes of paediatric cutaneous lymphomas, particularly emphasizing their distinctive features in comparison to their adult counterparts and exploring the less common subtypes. Further larger-scale studies are warranted to better characterize these entities and to achieve a more rapid and accurate diagnosis.

FIGURE 1

Clinical and histological presentations of lymphomatoid papulosis and mycosis fungoides. (a) Lymphomatoid papulosis. Generalized papular eruption. Some of these lesions show bullous and necrotic evolution. (b) Lymphomatoid papulosis, type A. Scattered and clustered large atypical cells, along with small lymphocytes, histiocytes and a few eosinophils. Haematoxylin and eosin (H&E), original magnification × 100. (c) Lymphomatoid papulosis. Generalized papular eruption in different stages of evolution. (d) Lymphomatoid papulosis, type A. Wedge‐shaped infiltrate with perivascular and periadnexal involvement, characterized by several large, atypical cells admixed with some granulocytes. H&E stain, original magnification × 20. (e) Mycosis fungoides. Erythematous finely scaling plaque on the right side of the abdomen. (f) Mycosis fungoides. Band‐like lymphoid infiltrate with prominent epidermotropism and intraepidermal collections of lymphocytes (Darier's nests). H&E stain, original magnification × 200. (g) Mycosis fungoides. Multiple hypopigmented patches. (h) Mycosis fungoides. Epidermal hyperplasia and acanthosis with some necrotic keratinocytes associated with an infiltrate of atypical lymphocytes in the superficial dermis, showing epidermotropism. H&E stain, original magnification × 100.

FIGURE 2

Clinical and histological presentations of rarer subtypes. (a) Cutaneous peripheral T‐cell lymphoma, not otherwise specified. Erythematous plaques on the buttock. (b) Cutaneous peripheral T‐cell lymphoma, NOS. Perivascular and periadnexal atypical medium‐ and large‐sized lymphoid infiltrate, with focal epidermotropism. Haematoxylin and eosin (H&E), original magnification × 200. (c) Cutaneous anaplastic large‐cell lymphoma. Multiple ulcerated tumours and plaques on the trunk. (d) Cutaneous anaplastic large‐cell lymphoma. Diffuse infiltrate characterized by cohesive sheets of large cells. H&E stain, original magnification × 200. (e) Subcutaneous panniculitis‐like T‐cell lymphoma. Subcutaneous nodules, covered by slightly erythematous/brown skin, on the trunk. (f) Subcutaneous panniculitis‐like T‐cell lymphoma. A dense infiltration of small‐medium‐sized pleomorphic lymphocytes involving the subcutaneous fat. H&E stain, original magnification × 200. (g) Cutaneous marginal zone lymphoma. Solitary nodule on the cheek. (h) Cutaneous marginal zone lymphoma. Marginal zone cells (‘centrocyte‐like’) with abundant cytoplasm mixed with plasma cells, small lymphocytes and eosinophils. H&E stain, original magnification × 100.