Extranodal NK/T-cell lymphoma presented as panniculitis of breast in a male patient: A case report

Breast lymphoma is uncommon, accounting for approximately 0.15% of malignant breast lesions. It usually originates from lymphocytes in breast parenchyma and ipsilateral axillary lymph nodes. In breast, diffuse large B-cell lymphoma is more common than T-cell lymphoma. Here, we report a rare case of cutaneous natural killer/T-cell (NK/T) lymphoma mimicking panniculitis of the breast, that was presented as a growing palpable mass and pain in both breasts of a 33-year-old male patient. Ultrasonographic appearance was extensive hyperechogenicity in subcutaneous fat layer of mammary areas, mimicking panniculitis or fat necrosis. Pathologically, a histologic subtype was extranodal natural killer/T-cell lymphoma, nasal-type.