ABCL-089: Masquerading as Breast Cancer: Rare Metastatic Peripheral T-Cell Lymphoma

Document Type

Conference Proceeding

Publication Date

9-1-2025

Publication Title

Clin Lymphoma Myeloma Leuk

Abstract

Peripheral T-cell lymphoma (PTCL) is a rare subtype of non-Hodgkin lymphoma that typically originates in the lymph nodes and rarely involves the breast. Here, we present a case in which PTCL not only originated in the breast but also mimicked an aggressive primary breast cancer—an exceptionally rare diagnosis, with only 18 documented cases in the literature. Patient: A 76-year-old debilitated female with diabetes, hypertension, and blindness from glaucoma presented after a mechanical fall. During evaluation, she reported a 3-week history of left breast pain with intermittent malodorous discharge. Years prior, a similar episode had resolved after incision and drainage and antibiotics for a presumed abscess. Results and Interventions: On examination, the breast was indurated without active discharge, although purulent and bloody drainage was observed in the emergency department. There was no lymphadenopathy or hepatosplenomegaly. Surgery attempted drainage unsuccessfully, prompting biopsy and oncology evaluation. Imaging added to the diagnostic dilemma. A recent mammogram was unremarkable. Noncontrast head computed tomography showed unchanged skull lucencies. However, brain MRI revealed new lytic calvarial lesions without brain involvement. Labs showed pancytopenia. Workup ruled out primary breast malignancy and multiple myeloma. Ultimately, immunohistochemistry showed a distinct but non-specific T-cell marker profile (BETAF1, CD8, TIA1, CD3, CD43, CD56, CD15, BCL2, GATA3, CD79a, c-MYC), leading to the diagnosis of PTCL-not otherwise specified (PTCL-NOS) with skull metastases and bone marrow infiltration. Outcome: Given the aggressive disease course, lack of defined treatment protocols, and poor prognosis, the patient opted for hospice care. Conclusions: This case illustrates several key challenges: • rare extranodal breast presentation. • clinical mimicry of primary breast carcinoma. • diagnostic confusion from lytic skull lesions and pancytopenia. • delayed diagnosis due to non-specific immunohistochemistry. • lack of data to guide management—only 4 of 18 known PTCLbreast cases involved metastasis. This case underscores the need for heightened suspicion in atypical breast lesions and highlights the diagnostic complexity and treatment uncertainty of rare extranodal lymphomas like PTCL.

Volume

25

First Page

S721

Last Page

S722

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