Solid pseudopapillary tumour

Cytopathology of solid pseudopapillary neoplasm

Solid pseudopapillary tumour (SPT), also known as solid pseudopapillary neoplasm (SPN), is a rare type of tumor that primarily affects the pancreas. It is an uncommon entity, accounting for 1-2% of all pancreatic neoplasms. SPTs are of low malignant potential but can behave aggressively. The World Health Organization (WHO) classifies it as a low-grade malignant tumor of the exocrine pancreas. This tumor was first described by Virginia Kneeland Frantz in 1959, hence it is sometimes referred to as Frantz's tumor.

Epidemiology

SPTs predominantly affect young women in their second or third decades of life. There is a marked female predilection with the female to male ratio being approximately 10:1.

Pathophysiology

The exact cause of solid pseudopapillary tumors is unknown. These tumors are characterized by solid and cystic areas, with the solid areas showing pseudopapillary structures. Histologically, they are composed of monomorphic cells forming solid and pseudopapillary patterns. The cells are polygonal with eosinophilic cytoplasm and uniform nuclei. Immunohistochemically, the tumor cells express vimentin, beta-catenin, and CD10, but are typically negative for pancreatic enzymes.

Clinical Presentation

Patients with SPTs often present with nonspecific symptoms, which may include abdominal pain, a palpable abdominal mass, or nausea. In some cases, the tumors are discovered incidentally during imaging studies performed for unrelated reasons.

Diagnosis

The diagnosis of SPT is primarily based on imaging techniques such as ultrasound, computed tomography (CT) scan, and magnetic resonance imaging (MRI). These imaging modalities can reveal a well-encapsulated mass with both solid and cystic components. Definitive diagnosis, however, requires histopathological examination of the tumor tissue, often obtained through surgical resection.

Treatment

Surgical resection is the treatment of choice for SPTs and can be curative. The type of surgery depends on the tumor's location within the pancreas. Options include enucleation, distal pancreatectomy, or Whipple procedure. The prognosis after complete surgical resection is excellent, with a high 5-year survival rate.

Prognosis

The prognosis for patients with SPT is generally favorable, especially when the tumor is completely resected. Recurrence and metastasis are rare but can occur, particularly in cases where the tumor is not completely removed or if the tumor exhibits more aggressive features.