Primary Cutaneous Anaplastic Large Cell Lymphoma With Rare Extracutaneous Disseminated Disease: A Case Report.

Primary cutaneous anaplastic large cell lymphoma (pcALCL) is a CD30 + lymphoproliferative disorder with generally favorable outcomes and infrequent extracutaneous spread, usually limited to local lymph nodes. However, there may be extensive histologic overlap with more aggressive CD30 + lymphomas, such as large cell transformation of mycosis fungoides or secondary skin involvement by anaplastic lymphoma kinase (ALK)-negative anaplastic large cell lymphoma. Definitive diagnosis relies on clinicopathologic correlation. We report on a 26-year-old woman who presented to our institution with progressive lower extremity wounds for several months, previously treated with antibiotics and vacuum-assisted closure dressings. Consultation with dermatology and 2 separate biopsies eventually led to the diagnosis of pcALCL. Subsequent imaging revealed stage IV disease with innumerable intensely fluorodeoxyglucose (FDG)-avid subcutaneous, intramuscular, and visceral foci, but paucity of lymph node involvement. The patient's condition deteriorated, and she died during her hospitalization. This case reviews the clinicopathologic findings of pcALCL, emphasizes the importance of clinicopathologic correlation in differentiating between CD30 + lymphoproliferative disorders, highlights the extremely rare phenomenon of systemic intramuscular and visceral disseminated disease occurring in pcALCL, and discusses implications for prognosis.