Image of the Month—Diagnosis

Solid pseudopapillary tumor of the pancreas (SPT) is an extremely rare neoplasm of the pancreas, accounting for only 1% to 2% of pancreatic neoplasms. An SPT is a tumor of the primitive pancreatic epithelial cells, with predominance of exocrine features but having the capacity for dual (exocrine and endocrine) differentiation.¹ Solid pseudopapillary tumor of the pancreas usually occurs in young girls, with more than 50% of patients younger than 19 years,² and are more common among black and Asian populations.³ Many of these tumors are asymptomatic and present as mild abdominal pain and a lump.

The characteristic sonographic findings of SPT are a well-encapsulated, cystic, and solid mass. Sometimes the mass looks solid, or it may have internal septations or calcifications.⁴ Contrast-enhanced computed tomography will show a large, hypodense lesion with a few low-attenuation areas. Because of such findings, these lesions are often mistaken for pseudocysts.⁵

Treatment of SPT includes the Whipple procedure for masses found at the head of the pancreas and distal pancreatectomy for distal growth.³ Solid pseudopapillary tumors of the pancreas usually grow slowly; however, metastasis to the liver and peritoneum has been described.^6,7 The most distinctive feature on histopathologic examination is pseudopapillae covered by several layers of epithelial cells. Nuclei are ovoid and folded, with indistinct nucleoli and few mitoses. Hyaline globules and a collection of foam cells may be present.⁸ Solid pseudopapillary tumors of the pancreas show strong cellular immunoreactivity for vimentin and focal, weak keratin reactivity. Neuron-specific enolase, α₁-antitrypsin, and α₁-antichymotrypsin stains are also positive.⁹

Correspondence: Chirag S. Desai, MS, DNB, Department of Surgery, Seth G. S. Medical College and King Edward Memorial Hospital, Acharya Donde Marg, Parel, Mumbai 400 012, India (csdesai@gmail.com).

Accepted for Publication: April 27, 2005.