Differentiating intrapancreatic accessory spleen from a pancreatic neuroendocrine tumor or metastasis by the “bridge sign”

An accessory spleen (splenule) may be present in 10%–30% of the general population.[1] Majority of these are located around the splenic hilum with a smaller number within the pancreatic tail.[2] The intrapancreatic accessory spleens not infrequently cause diagnostic confusion (especially with neuroendocrine tumors of the pancreas or pancreatic metastases) on imaging modalities such as CT, MR, and US. Even fine-needle aspiration or surgery has been done for patients with intrapancreatic accessory spleens due to continued concern for a pancreatic neoplasm. Figure 1 shows an intrapancreatic accessory spleen during EUS where a round, homogeneous, well-defined lesion is seen in the pancreas tail that may be indistinguishable from a neuroendocrine tumor or a metastatic lesion. However, on dynamic real-time EUS imaging with careful transducer movement, the lesion is seen to be connected to the spleen with a bridge of splenic tissue. The authors would like to name it “the bridge sign” [Figure 2]. Nothing else is needed at this point. This simple technique saves the patient an EUS-FNA, diagnostic confusion, surgery, anxiety, and health-care dollars. Let's not forget this dynamic EUS imaging aspect before reaching for the biopsy needle!

Figure 1.

EUS showing a round, homogeneous, well-defined lesion in the pancreatic tail. Differential diagnosis includes intrapancreatic accessory spleen or a pancreatic neuroendocrine tumor

Figure 2.

Dynamic EUS imaging reveals the “bridge sign” where the lesion is connected to the spleen by a bridge of tissue. Diagnosis: intrapancreatic accessory spleen

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