Successful treatment of pancreatic accessory splenic hamartoma by laparoscopic spleen-preserving distal pancreatectomy: A case report

BACKGROUND: Pancreatic accessory spleen (PAS) is an uncommon congenital abnormality of the spleen. Spleen hamartoma (SH) is also rare. Moreover, hamartoma in the PAS has not been reported thus far. We report the first case here. CASE SUMMARY: A 26-year-old male presented with a one-month history of left upper quadrant abdominal pain, and computerized tomography (CT) examination suggested a mass in the pancreas tail. The patient then attended our hospital for diagnosis and treatment. Ultrasonography, CT, and magnetic resonance imaging revealed a solid mass with cystic degeneration growing from the tail of the pancreas. The tumor marker carbohydrate antigen 19-9 (CA19-9) increased to 96.7 U/mL (normal range 0-37 U/mL). An epidermoid cyst in a PAS was considered preoperatively. However, a malignant tumor cannot be ruled out. We performed laparoscopic surgery, and two pancreatic masses were found growing from the pancreatic tail. The two masses were so closely connected that preoperative imaging examinations suggested only one mass. We carefully isolated the masses from the splenic artery and vein. A laparoscopic spleen-preserving distal pancreatectomy was successfully performed. On pathological examination, the masses were well-defined, homogeneous red-tan, 4 × 3, and 4.5 × 1.5 in size, respectively. One of them was cystically degenerated. On microscopical examination, the mass contained unorganized small slit-like vascular channels enclosing red blood cells and lined with plump endothelial cells. No area of cytologic atypia was identified. Focal lymphoid aggregates were found in the intravascular areas. White pulp or fibrosis was not observed. The final diagnosis was pancreatic accessory SH with cystic degeneration. After the operation, CA19-9 was reduced to normal. The patient recovered well, and the 34-mo follow-up period was uneventful. CONCLUSION: Here, we report the first case of pancreatic accessory SH. A laparoscopic spleen-preserving distal pancreatectomy was successfully performed. The patient recovered well and had a good prognosis.