Primary Cutaneous Anaplastic Large Cell Lymphoma in a Patient With Li Fraumeni Syndrome.

Li-Fraumeni syndrome (LFS) is an inherited cancer predisposition syndrome caused by germline TP53 mutations and is associated with an increased risk of several malignancies. Although breast implant-associated anaplastic large cell lymphoma has been reported in patients with LFS, primary cutaneous anaplastic large cell lymphoma has not previously been described. We report a case of primary cutaneous anaplastic large cell lymphoma in a 64-year-old man with LFS harboring a germline TP53 p.R196* mutation who presented with a solitary ulcerated nodule on the left anterior thigh. Histopathologic examination demonstrated an ulcerated dermal infiltrate of large atypical CD30-positive T lymphocytes admixed with small lymphocytes and eosinophils. Immunophenotyping showed expression of CD3, CD2, CD4, CD30, CD43, and CD45, with weak CD5 expression and loss of CD7 and EMA. Targeted exome sequencing identified the patient's known germline TP53 mutation together with additional somatic mutations and copy number alterations, whereas whole-body positron emission tomography/computed tomography demonstrated no evidence of systemic disease. The lesion was completely excised, and radiotherapy was deferred because of the patient's underlying LFS and associated risk of radiation-induced malignancy. The patient remains disease-free 36 months after diagnosis. This case expands the spectrum of lymphoid malignancies reported in patients with LFS and highlights the importance of recognizing hereditary cancer predisposition syndromes when selecting treatment strategies for primary cutaneous lymphomas.