Needle in A Haystack: A Rare Case of Subcutaneous Panniculitis-Like T-Cell Lymphoma of the Breast: A Case Report

Subcutaneous panniculitis-like T-cell lymphoma (SPTCL) is a rare primary cutaneous lymphoma of cytotoxic αβ T cells that mimics panniculitis. This report details the case of a 23-year-old woman who presented with fever, multiple left arm and axillary subcutaneous swellings, and was empirically treated with anti-tubercular therapy (ATT). After 5 months of ATT, she developed a left breast mass and the subcutaneous nodules became refractory, for which she underwent evaluation with digital mammography, ultrasound, and positron emission tomography-computed tomography, which showed diffuse skin and subcutaneous thickening with no mass. Histopathology with immunohistochemistry demonstrated a predominantly subcutaneous lobular infiltrate of atypical lymphocytes, establishing SPTCL. She was subsequently treated with Cyclosporine and systemic corticosteroids, resulting in clinical regression. There are exceedingly few reports of SPTCL of the breast and none documented in the Indian radiology literature. Distinguishing SPTCL from septo-lobular panniculitis and inflammatory breast diseases is challenging; heightened awareness facilitates timely diagnosis and appropriate therapy.