Primary pulmonary lymphomas (PPLs) are very uncommon types of lymphomas, usually B-cell-derived lymphomas; reports of primary pulmonary peripheral T-cell lymphoma (PTCL) are not commonly reported. These patients are diagnosed with PTCL-not otherwise specified (PTCL-NOS) since they cannot be further categorized into discrete disease categories. PTCL-NOS is the most common subtype, accounting for about 22% of PTCL cases in Asia and 30–35% of PTCL cases in Europe and North America. Most cases with PTCL-NOS manifest as nodal lymphomas, yet extra-nodal involvement during the disease’s early stages or relapses is not unusual. We present a case of a 59-year-old female with a history of left breast mucinous ductal carcinoma who presented with multiple lung nodules initially mistaken for metastatic breast carcinoma. Specific histomorphologic features and immunohistochemistry analysis confirmed the diagnosis of primary peripheral pulmonary T-cell lymphoma, not otherwise specified. We review the pertinent literature, including clinical presentation, diagnosis, pathology, and management.