Ki-1+ anaplastic large cell lymphoma in a child with unpredictable clinical course

Pediatric Cutaneous Hematologic Disorders: Cutaneous Lymphoma and Leukemia Cutis: Experience of a Tertiary-Care Pediatric Institution and Review of the Literature

BACKGROUND

Cutaneous hematologic malignancies are rare in children, and the literature about them is still sparse.

OBJECTIVE

The purpose of our study was to report our experience with pediatric cases of cutaneous hematologic disorders and describe their clinical and histological features.

METHODS

Data were retrospectively collected from the histopathologic database of the CHU Sainte-Justine, University of Montreal, Montreal, Canada. All patients up to 18 years of age with a diagnosis of a primary cutaneous lymphoma (including lymphomatoid papulosis), secondary cutaneous lymphoma or cutaneous manifestations of leukemia, followed from 1980 to 2019 at our center were reviewed.

RESULTS

Thirty-six patients were included. Age at presentation ranged from birth to 18 years of age (mean 7.83 ± 5.16; median 7.0). Ten different hematologic disorders were identified according to the WHO-EORTC classifications: lymphomatoid papulosis (10 cases), mycosis fungoides (6 cases), anaplastic large cell lymphoma (4 cases), pre-B acute lymphoid leukemia (5 cases), primary cutaneous marginal zone B-cell lymphoma (4 cases), primary cutaneous CD4⁺medium T-cell lymphoproliferative disorder (1 case), extranodal NK/T-cell lymphoma (1 case), hydroa vacciniforme-like lymphoproliferative disorder (1 case), B-cell lymphoblastic lymphoma (1 case) and acute myeloid leukemia (3 cases).

CONCLUSION

The most common subtype of cutaneous hematologic disease in our single institution study was lymphomatoid papulosis (type A and type C), followed by mycosis fungoides. Recognition of this large clinical and histological spectrum by dermatologists is important because diagnosis is often established by biopsy of skin lesions, even in secondary cutaneous cases. Moreover, the clinicopathological correlation is of utmost importance for the final diagnosis of those pathologies.

The spectrum of cutaneous lymphomas in patients less than 20 years of age

Cutaneous lymphomas are rare in young patients and are mostly represented by mycosis fungoides and its variants and CD30+ lymphoproliferative disorders (lymphomatoid papulosis [LYP] and anaplastic large T-cell lymphoma). We report our observations in a series of 69 patients less than 20 years of age who presented either with primary cutaneous lymphoma (n = 62) or with secondary manifestations of extracutaneous disease (n = 7). Clinicopathologic features permitted classification of the cases into the following diagnostic categories: mycosis fungoides (n = 24, all primary cutaneous), anaplastic large T-cell lymphoma (n = 13, all primary cutaneous), LYP (n = 11, all primary cutaneous), subcutaneous "panniculitis-like" T-cell lymphoma (n = 1, primary cutaneous), small-medium pleomorphic T-cell lymphoma (n = 2, all primary cutaneous), natural killer (NK)/T-cell lymphoma, nasal-type (n = 1, secondary cutaneous), follicle center cell lymphoma (n = 1, primary cutaneous), marginal zone B-cell lymphoma (n = 7, all primary cutaneous), B-lymphoblastic lymphomas (n = 6, 3 primary and 3 secondary cutaneous), specific cutaneous manifestations of Hodgkin disease (n = 1, secondary cutaneous), and acute myeloid leukemia (n = 2, both secondary cutaneous). Cutaneous lymphoma in children should be differentiated from benign skin disorders that may simulate them. In particular, mycosis fungoides and LYP in this age group may present with clinicopathologic features reminiscent of inflammatory disorders such as pityriasis alba, vitiligo, pityriasis rosea, and pityriasis lichenoides et varioliformis acuta. Even in secondary cutaneous lymphomas, skin manifestations may be the first sign of the systemic disease, and a diagnosis may be achieved on examination of histopathologic specimens of a cutaneous lesion. Our study illustrates the wide spectrum of cutaneous lymphomas and leukemias in patients less than 20 years of age and underlines the need for proper interpretation of these lesions by dermatologists and dermatopathologists.