Collision Tumor of the Uterine Corpus: Primary EBV-positive Diffuse Large B-Cell Lymphoma and Endometrioid Carcinoma.
Qiuyue Chen, Zongchen Wei, Fang Tang
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Case in brief
A 63-year-old postmenopausal woman presented with vaginal bleeding, and ultrasonography showed a 2.3×1.0 cm mildly hyperechoic uterine corpus mass. Histology demonstrated intermixed low-grade endometrioid carcinoma and sheets of medium- to large-sized lymphoid cells. The lymphoid cells expressed CD20, most were positive for EBV-encoded small RNA by in situ hybridization, and molecular analysis showed clonal B-cell receptor gene rearrangement, supporting EBV-positive diffuse large B-cell lymphoma. The carcinoma cells expressed estrogen receptor and cytokeratin 18. The findings established a collision tumor comprising the two malignancies.
What made this case unusual
The uterine corpus lesion contained both EBV-positive diffuse large B-cell lymphoma and endometrioid carcinoma as a collision tumor, an association the report states had not previously been described.
Diagnostic / clinical pearl
In a uterine tumor with prominent lymphoid cells, distinguish a true lymphoma–carcinoma collision from endometrioid carcinoma with florid reactive lymphocytes or dedifferentiated carcinoma using morphology, immunophenotype, and molecular findings.