FDC sarcoma is a rare tumour originating from the antigenprocessing cells of the lymphoid follicles. It predominantly affects young adults with no gender predilection. It presents with lymph node enlargement, or abdominal pain if it develops in the small intestine, pancreas or mesocolon, and may involve other extranodal sites (tonsil, palate, soft tissues of the neck, breast). 1 FDC sarcoma is considered to be an intermediate grade malignancy with a tendency for local recurrence, but also has metastatic potential (lung, liver, peritoneum and lymph node) and a mortality rate of 17%. 2 Immunohistochemistry is necessary to establish the diagnosis. Positive CD21, CD35, R4 ⁄23, Ki-M4, Ki-M4p and Ki-FDC1p best demonstrate the dendritic nature of the tumour. 3 The lack of staining with these antibodies will help to exclude ectopic meningoma, ectopic thymoma and malignant fibrous histiocytoma. The tumour may show occasional positivity for S-100 protein, muscle-specific actin and epithelial membrane antigen but is negative for cytokeratins and vascular markers. 4 The other differential diagnoses of FDC sarcoma include undifferentiated carcinoma, malignant melanoma and large cell lymphoma. 3 Complete surgical resection with adjuvant
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