Pancreatoblastoma (Pancreatoblastoma)
Pancreatoblastoma is a rather rare malignant neoplasm of the pancreas. In clinical practice, this tumor is most commonly diagnosed in infants or young children. Patients with a genetic predisposition, primarily children suffering from Beckwith–Wiedemann syndrome (Beckwith–Wiedemann syndrome), constitute a special risk group.
On diagnostic imaging, pancreatoblastoma is typically defined as a heterogeneous solid-cystic mass. A characteristic diagnostic sign during contrast-enhanced studies is variable contrast enhancement of different parts of the tumor.
Solid-cystic papillary epithelial tumor
This neoplasm is widely known in the medical literature as Frantz's tumor (Frantz tumour). The pathology has a pronounced demographic specificity: a relatively high incidence is noted among adolescents, with the vast majority of patients being female.
Magnetic resonance imaging (MRI) is the preferred method for detailed evaluation of this mass:
- Visualized as a large, well-circumscribed mass.
- Areas of cystic or hemorrhagic degeneration, as well as calcification sites, are frequently revealed within the tumor structure.
- A specific sign is the presence of a low-intensity fibrous rim (capsule).
- On T2-weighted images (T2WI), Frantz's tumor may appear as a heterogeneous hyperintense mass surrounded by a thick hypointense margin.
Islet cell tumours (Islet cell tumours)
Islet cell neuroendocrine tumors are closely associated with severe hereditary disorders, such as multiple endocrine neoplasia type 1 (MEN type 1) and von Hippel–Lindau disease (von Hippel–Lindau disease). Functioning tumors are most commonly detected in children. The most frequent of these is insulinoma, while gastrinoma, VIPoma (VIPoma), and glucagonoma are less common.
Radiologic diagnostic features: Often these neoplasms are extremely small, due to which they may not be detected by standard US, CT, and MRI. However, when using diffusion-weighted imaging (DWI) on MRI, insulinoma may demonstrate moderate diffusion restriction and cause deviation of the main pancreatic duct. In diagnostically suspicious cases, radioisotope studies are indicated.
Assessment of adjacent organs: Spleen (Spleen)
During a comprehensive abdominal examination, the spleen must be evaluated. The use of a high-frequency linear transducer during US is the best method for detecting small parenchymal lesions (e.g., focal fungal infection). MRI remains the preferred method for investigating larger (greater than 1 cm) masses of unclear etiology.
Accessory spleens (Accessory spleens) are a common normal variant that has no clinical significance. On high-frequency US, a reactive spleen may acquire a "spotted" (spotted) appearance—this is a normal variant that should not be confused with multifocal infection. On MRI in newborns, the spleen is hypointense on T1WI and T2WI, but as the ratio of white pulp to red pulp increases, the picture becomes identical to the adult norm by the age of 8 months.
Recommended upper limit of normal for the longitudinal size of the spleen on US (in the coronal plane):
| Age (months) | Upper limit of normal (mm) |
|---|---|
| 1–3 | 70 |
| 4–6 | 75 |
| 7–9 | 80 |
| 12–30 | 85 |
| 36–59 | 95 |
| 60–107 | 105 |
| 108–131 | 110 |
| 132–155 | 115 |
| 156–200 | 120 |
Data are based on an ethnically homogeneous sample. Interobserver variability must be taken into account.
Pathological changes of the spleen
The spectrum of splenic pathologies in pediatrics includes a number of specific conditions:
- Splenomegaly: can be caused by infectious mononucleosis, Langerhans cell histiocytosis (Langerhans cell histiocytosis), or storage diseases (Gaucher disease, Niemann-Pick disease, mucopolysaccharidosis).
- Wandering spleen (Wandering Spleen): associated with prune-belly syndrome (prune-belly syndrome), prior surgeries, and gastric volvulus. This condition predisposes to organ torsion and infarction.
- Focal lesions: solitary and multiple lesions are more often of infectious origin (abscesses, fungi).
- Calcifications: occur in granulomatous diseases, infarctions, hemangiomas, hamartomas, and hydatid (echinococcal) cysts.
- Laterality disorders: asplenia (more often associated with immunodeficiency) and polysplenia (associated with continuation of the hemizygous vein, preduodenal portal vein, biliary atresia, and bilateral left-sidedness of the lungs). On US, the spleen must always be located near the greater curvature of the stomach. Radioisotope studies may be required to confirm asplenia.
Briefly: answers to topical questions
What are the histological features of pancreatoblastoma?
The histological features of pancreatoblastoma are not detailed in the text; it is only indicated that it belongs to rare and mixed histological types of neoplasms (code 8971/3).
The following macroscopic and clinical characteristics are additionally described:
- Pancreatoblastoma (Pancreatoblastoma) is a rare tumor visualized as a heterogeneous solid-cystic mass with variable contrast enhancement.
The pathology occurs predominantly in infants and young children with a predisposition in the form of Beckwith–Wiedemann syndrome (Beckwith–Wiedemann syndrome).
What are the main symptoms and clinical manifestations of insulinoma in children?
Specific clinical manifestations of insulinoma in children are not described; it is only noted that this is the most frequent functioning tumor in this age group.
The following clinical features are known:
- Islet cell tumours (Islet cell tumours) are associated with multiple endocrine neoplasia type 1 and von Hippel–Lindau disease (von Hippel–Lindau disease).
In adult patients (older than 30 years), a hormone-active insulinoma may act as an extracranial cause of epileptic syndrome, the first symptoms of which are paroxysms, seizures, twilight states, and psychosensory disorders.
To memorize the patient profile with Frantz's tumor: "Frantz's tumor is Feminine" (most commonly occurs in females and adolescent girls).
Class and exam questions
What hereditary syndromes are associated with pancreatic tumors in children?
Beckwith-Wiedemann syndrome increases the risk of developing pancreatoblastoma. Multiple endocrine neoplasia type 1 (MEN 1) and von Hippel–Lindau disease are strongly associated with islet cell tumors.
What do solid pseudopapillary neoplasms (Frantz tumors) look like on MRI?
On MRI, it is visualized as a large, well-circumscribed mass with areas of cystic and hemorrhagic degeneration. On T2WI, it has a heterogeneous hyperintense structure with a characteristic thick hypointense fibrous rim.
Why can insulinomas be difficult to locate on ultrasound or CT?
Islet cell tumors, such as insulinoma, are often very small and blend with the parenchyma. Their detection frequently requires MRI with diffusion-weighted imaging (DWI) or specialized radioisotope methods.
What does a «speckled» appearance of the spleen mean on an ultrasound in a child?
When using a high-frequency transducer, a reactive spleen may look "spotted" (spotted). This is a normal variant and should not be misconstrued as a sign of multifocal fungal infection.
What else to study on this topic
- Radioisotope diagnostics of pancreatic neuroendocrine tumors
- Storage diseases (Gaucher, Niemann-Pick) and their manifestations on abdominal US
- Beckwith-Wiedemann syndrome: systemic manifestations and oncological risks
- Differential diagnosis of focal infectious splenic lesions
- Laterality disturbance syndromes (asplenia and polysplenia) and associated congenital heart defects
Master the entire topic in the "Diagnostic Radiology" course
This is a summary. The course covers everything tested in classes and exams.
- Complete methodical guide on the topic «Pancreatic Neoplasms» and another 2,199 pages of the subject
- Assignments and quizzes after every topic — just like in a colloquium
- AI tutor answers questions on the topic anytime
- 10 video lessons on the subject
Other Topics in "Pediatric Diagnostic Radiology"
Prepared by WhiteCoat Pro faculty in accordance with the medical school curriculum. For educational purposes only.