Angiocentric Variant of Primary Cutaneous CD30-Positive Anaplastic Large Cell Lymphoma: A Case Report and Literature Review.

Anaplastic large cell lymphoma (ALCL) is part of the spectrum of CD30-positive lymphoproliferative disorders within cutaneous T-cell lymphomas. These disorders account for approximately 25%-30% of all primary cutaneous lymphomas (PCLs). Primary cutaneous ALCL (pcALCL) is an uncommon entity with heterogeneous clinical and histopathologic features, often posing a diagnostic challenge. We report a 79-year-old man who presented with a three-month history of a non-healing ulcer on the right lower limb following minor trauma. The lesion measured 6.7 × 9.8 × 0.3 cm and showed irregular erythematoviolaceous borders with areas of eschar. Histopathologic evaluation revealed a dense infiltrate of large atypical mononuclear cells with pleomorphic nuclei, prominent nucleoli, and atypical mitoses, accompanied by angiocentric and angiodestructive features. Immunohistochemistry demonstrated CD30 positivity in more than 75% of atypical cells and negative anaplastic lymphoma kinase (ALK) expression, confirming pcALCL. The patient responded favorably to electron beam radiotherapy. This case underscores the importance of early biopsy in atypical or treatment-refractory ulcers and highlights the diagnostic relevance of recognizing rare variants such as the angiocentric subtype.