Intrapancreatic accessory spleen mimicking malignant tumor: three case reports

Imaging‑based diagnosis of intrapancreatic accessory spleen: A case report

During a routine ultrasound examination of the abdomen, a 60-year-old male patient was diagnosed with mass in the tail of the pancreas. However, computed tomography (CT) suggested that the lesion was an intrapancreatic accessory spleen (IPAS). IPAS is a congenital anomaly, which usually does not present with symptoms. IPAS occurs during embryologic splenic development when a portion of the splenic tissue fails to fuse with the main body of the spleen. IPAS does not require treatment, except when it is combined with idiopathic thrombocytopenic purpura. In the present case, the diagnosis of IPAS was confirmed using magnetic resonance imaging (MRI). On CT and MRI, the IPAS had a density and intensity comparable with that of the spleen in all plain and contrast-enhanced phases. Due to comorbidities, the patient refused further evaluation or surgery. The lesion was periodically monitored using CT every 1-2 years. Since the tumour was stable during the 7-year follow-up, it was concluded that it was an IPAS. In patients that cannot undergo surgery, a characteristic location (near the spleen) and imaging features (such as a 'zebra-patterned' enhancement in the arterial phase on CT and high signal intensity on diffusion-weighted imaging sequences on MRI, which is comparative to that of the normal spleen) may allow for a diagnose of IPAS with a high level of certainty. Being aware of this condition could aid a correct diagnosis of IPAS and prevent unnecessary surgery.

Intrapancreatic accessory spleen mimicking pancreatic insulinoma with intrapancreatic metastasis in a cat

An 11-year-old neutered male Domestic Shorthair cat presented with a 3-month history of hypoglycemia, two episodes of seizure, and intermittent tick-like signs. Serum biochemistry revealed severe hypoglycemia associated with high insulin concentrations. Dynamic abdominal computed tomography (CT) indicated two pancreatic masses, which were enhanced most during the late arterial phase but had different degrees and variations of attenuation. Partial pancreatectomy was performed. Histopathology and immunohistochemistry confirmed that one mass was an insulinoma and the other was an ectopic splenic tissue, consistent with the differences in imaging findings. When an intrapancreatic lesion with hyper-attenuation on dynamic abdominal CT is detected, not only insulinoma or metastasis of malignancies but also intrapancreatic accessory spleen (IPAS) should be considered as differential diagnoses.

SPECT/CT with 99mTc labelled heat-denatured erythrocyte to detect thoracic and abdominal splenosis

Scintigraphy with ^99mTc labelled heat-denatured erythrocyte (DRBC) allows non invasive diagnosis of heterotopic splenic tissue implantation (splenosis) following splenic trauma or surgery. Single-photon emission computed tomography (SPECT) combined with computed tomography (CT) improves diagnostic accuracy of planar imaging through a more precise localization of functional findings. We report about two cases of splenosis occurring many years after splenectomy. ^99MTc-DCRBC scintigraphy was used for differential diagnosis of metastatic disease in one case and to assess an incidental finding at bone scan in the second one. SPECT/CT increased specificity of planar imaging, expecially revealing combined (thoracic and abdominal) splenosis. (www.actabiomedica.it)