An Uncommon Guest to the Axillary Lymph Node – A Case Report of Nodal Metastasis of Synovial Sarcoma

Abstract Introduction Synovial sarcoma is a rare and aggressive soft tissue sarcoma having poor prognosis with high tendency to recur and metastasize distantly. Localised disease shows a better prognosis than metastasis. The most common sites of metastasis are lungs, bone and liver. Lymph node is a less common site of metastasis. Case Presentation A 57-year-old male presented with an axillary region swelling with no other symptoms. Two yellowish to grey white to grey brown masses from the abdomen were excised and sent to histopathology. The cut surface of the larger mass showed three lymph nodes that were grey white and firm. The cut surface of the smaller mass showed two lymph nodes that are grey white and firm. Microscopy revealed complete effacement of architecture by pleomorphic spindle cells arranged in fascicles. These cells exhibited a high nuclear-cytoplasmic ratio, vesicular nuclei with prominent nucleoli, and brisk atypical mitoses (6–7/hpf). Tumor necrosis was present, and a subset of cells displayed epithelioid differentiation, arranged in nests. No extranodal extension was identified. Immunohistochemistry revealed positive TLE1, Synaptophysin, PanCK and Vimentin and a partial INI loss. S100, SMA and CD34 were negative. CT revealed multiple lesions at bilateral lungs, kidney, liver and lymphadenopathy in mediastinum and inguinal regions. This case was diagnosed as Synovial Sarcoma and was started on Doxorubicin. Conclusion Synovial sarcoma is an aggressive tumor that may show lymph node metastasis. Axillary lymph node swelling though rare maybe a presenting complaint of synovial sarcomas. It also expresses various markers including TLE1. Synaptophysin which is also a neuroendocrine marker may appear positive. This should be kept in mind as it is imperative to be considerate of the heterogeneity of marker expressions of synovial sarcomas and be vigilant while diagnosing these tumors.