Primary Thyroid Diffuse Large B-Cell Lymphoma with Spindle Cell Morphology: A Case Report

A Diffuse Large B-Cell Lymphoma (DLBCL) with spindle cell components is extremely rare and often misdiagnosed as a carcinoma or sarcoma. Here, we present a case of primary DLBCL with a spindle cell morphology arising in the thyroid, for which needle cytology was unsuccessful for obtaining a preoperative diagnosis. An 82-year-old female was examined for a rapid enlarging mass in the anterior neck area and computed tomography scanning showed a tumor that was 40 mm in size, without cyst or calcification. A left partial thyroidectomy was performed, followed by histological examinations revealed. Microscopy findings of the resected thyroid tumor revealed a diffuse or epithelioid pattern of round and polygonal cells mixed with the fascicles of spindle cells. In immunohistochemical results, all types of tumor cells showed positive staining for CD45, CD20, CD79a, CD10, and bcl-2, and were negative for CKAE1/AE3, TTF-1, MUN-1, CD3, CD5, bcl-2, IRTA-1, cyclin D1, c-myc, and EBER. Furthermore, a lymphocyte marker (CD45), B-cell markers (CD20 and CD79α). A lymphoma with spindle cell morphology is quite uncommon, and this variant can be difficult to diagnose. The present findings emphasized that pathologists remain aware of a possible lymphoma for a differential diagnosis of tumors with spindle cell components.