Abstract
Anaplastic large cell lymphomas (ALCLs) are a group of CD30 positive T-cell non-Hodgkin lymphomas, accounting for only 3% of all non-Hodgkin lymphomas. As per the 2017 World Health Organization updated classification, there are four variants of ALCL: anaplastic lymphoma kinase (ALK) positive, ALK negative, primary cutaneous, and breast-implant associated. The different variants of ALCL share overlapping clinical presentations and pathologic features, creating a diagnostic challenge. A 71-year-old woman with a past history of T-cell lymphoma presented with a progressively growing nodule on her back for approximately 3 months. Physical exam demonstrated a 8.0 x 8.0 cm pink nodular indurated plaque located on her left upper back. A punch biopsy of the lesion revealed medium to large mononuclear cells with nuclear pleomorphism, hyperchromasia, and scattered mitotic figures. Immunohistochemistry demonstrated cells that were positive for CD30 and negative for ALK. Based on clinical and histopathologic findings, a diagnosis of ALCL was rendered. Differential diagnosis included primary cutaneous ALCL and cutaneous involvement by systemic ALK(-) ALCL. This case demonstrates the importance of clinicopathologic correlation in diagnosing ALCL and guiding therapy.
Highlights
Anaplastic large cell lymphoma (ALCL) represents a group of CD30 positive T-cell non-Hodgkin lymphomas unified by common morphologic and immunophenotypic characteristics, but with a spectrum of clinical presentations and behaviors.[1]
Recognition of anaplastic lymphoma kinase (ALK) gene rearrangements in some ALCLs led to ALK being considered an important diagnostic and prognostic biomarker, and a key driver of ALCL pathobiology
Given the localized lesion without extracutaneous involvement, a diagnosis of primary cutaneous ALCL (PC-ALCL) was rendered and the patient was scheduled for radiation therapy
Summary
Anaplastic large cell lymphoma (ALCL) represents a group of CD30 positive T-cell non-Hodgkin lymphomas unified by common morphologic and immunophenotypic characteristics, but with a spectrum of clinical presentations and behaviors.[1] Recognition of anaplastic lymphoma kinase (ALK) gene rearrangements in some ALCLs led to ALK being considered an important diagnostic and prognostic biomarker, and a key driver of ALCL pathobiology. The different subtypes of ALCL share overlapping clinical presentations and pathologic features which can be diagnostically challenging.[1] Despite only accounting for 3-5% of all non-Hodgkin lymphomas, distinguishing between each ALCL subtype is important as treatment and prognoses vary.[2,3] ALK (-) ALCL mimics ALK (+) ALCL morphologically and January 2021 Volume 5 Issue 1. We describe the case of a patient who presented with an indurated nodular plaque which, upon biopsy and immunohistochemistry, was diagnostic of ALCL with differential diagnoses including cutaneous involvement by systemic ALK (-) ALCL and PC-ALCL
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