Axillary Nodal Metastasis with Papillary Morphology: An Uncommon Origin.

Background Metastases to axillary lymph nodes are commonly and readily confirmed by fine needle aspiration cytology (FNAC). Most likely, these arise from breast primaries. However, the diagnosis can become complicated when unusual cytomorphology is encountered. Case We report a 60-year-old woman presenting with bilateral axillary lymphadenopathies but without breast lesions. History showed increasing CA-125 levels. FNAC yielded carcinoma cells showing prominent papillary pattern, being composed of mild to moderately differentiated malignant cells, with focal abortive glandular formation and squamous metaplasia. IHC stains were done and the tumor cells were PAX-8 positive, but GATA-3 and GCDFP-15 negative. Coupled with the clinical history, a diagnosis of metastatic endometrioid adenocarcinoma was made. Conclusion Nodal metastases with papillary cytomorphology can rarely arise from nonbreast primaries. The presence of papillary pattern, particularly in the absence of a clinically detectable breast lesion, should raise the possibility of a metastasis. Correlation with patient history, imaging findings and judicious use of IHC studies are crucial for a correct diagnosis.