Serous cystic neoplasms (SCNs) of the pancreas are slow-growing benign tumors. They are mostly monitored without surgical management. Solid SCN is rare and differentiating it from hypervascular tumors of the pancreas using preoperative imaging may be difficult. A 69-year-old woman was referred to our department for surgical treatment of an enlarged pancreatic tail tumor with a size of 22mm based on the abdominal computed tomography (CT). At the age of 60, she underwent thyroidectomy for papillary thyroid carcinoma and mastectomy for breast cancer. Initially, consecutive annual CT examinations did not show signs of recurrence. However, after 9 years, a hypervascular pancreatic tumor was detected and assumed to be either a neuroendocrine tumor or metastasis. The patient underwent distal pancreatectomy, and the resected specimen was histopathologically diagnosed as solid SCN of the pancreas. Before being referred for pancreatic resection, this patient had been followed up with serial annual CT examinations for over 9 years after a previous malignant disease. Retrospectively, the abdominal CT scans showed that the pancreatic tumor already existed 5 years ago and had gradually increased in size thereafter. In this case report, we focused on the characteristics of solid SCN to address the difficulty in diagnosing this rare malignancy.