CXCL13 and neoplasm: Biopsy of the lung (Figure 6(2)) revealed similar morphologic features to the thigh mass; however, at this point, additional immunostaining for CD23 was performed and demonstrated diffuse positivity in the tumor cells which triggered re-evaluation of the soft tissue thigh mass with additional FDC markers such as clusterin and CXCL13, which showed diffuse positivity in the tumor cells (Figure 6(3)).