somatostatinoma

Common Signs and Symptoms of Somatostatinoma

Somatostatinomas are rare neuroendocrine tumors that can cause a range of symptoms, which can be vague and non-specific. The most common signs and symptoms of somatostatinoma include:

• Abdominal pain: This is one of the most common symptoms, affecting up to 40% of patients (8).
• Weight loss: Many patients experience weight loss due to the tumor's effect on digestion and nutrient absorption (8, 9).
• Jaundice: Jaundice or yellowish discoloration of the skin and eyes can occur when the tumor obstructs bile flow (12, 13).
• Diarrhea: Diarrhea is another common symptom, affecting up to 18% of patients (8, 14).
• Nausea and vomiting: Some patients may experience nausea and vomiting due to the tumor's effect on digestion (8).

Additional Symptoms

The symptoms of somatostatinoma can vary depending on the location of the tumor. In addition to the above-mentioned symptoms, some patients may experience:

• Obstructive jaundice: This occurs when the tumor obstructs bile flow, causing yellowish discoloration of the skin and eyes (7).
• Duodenal obstruction: The tumor can cause obstruction of the duodenum, leading to abdominal pain and vomiting (7).
• Gastrointestinal bleeding: In some cases, the tumor can cause gastrointestinal bleeding (7).

Somatostatinoma Syndrome

In rare cases, somatostatinomas can lead to a syndrome characterized by high blood sugar levels (diabetes), tummy pain, and diarrhea (14). This syndrome is known as somatostatinoma syndrome.

References:

• [8] Overall, 93% of patients with somatostatinomas had symptoms, with abdominal pain (40%), weight loss (26%), jaundice (23%), diarrhea (18%), nausea and vomiting (...
• [9] Jun 19, 2024 — The most common manifestations of somatostatinoma include abdominal pain and weight loss. However, presentation is variable based on tumor ...
• [12] These types do not produce somatostatinoma syndrome, but the growing tumor causes symptoms. In most cases, the tumor spreads to the liver and lymph nodes, leading to obstruction of parts of the intestine and gallbladder. Obstruction causes symptoms like: Swollen and painful abdomen. Jaundice or yellowish discoloration of the skin and eyes ...
• [13] Somatostatinoma (SSoma) is an extremely rare pancreatic neuroendocrine tumor or duodenal endocrine tumor (see these terms) that originates either in the pancreas (50%) or the gastrointestinal tract (50%) and mainly presents with non-specific symptoms of abdominal pain, weight loss, jaundice and diarrhea but, in approximately 20% of pancreatic cases, leads to a somatostatin hypersecretion ...
• [14] Somatostatinoma syndrome P Economopoulos and C Christopoulos Annals of Gastroenterology, 2001. Vol 14, Issue 4, Pages 252-260 ... Symptoms of somatostatinoma include high blood sugar levels (diabetes), tummy pain and diarrhoea.

Differential Diagnosis of Somatostatinoma

Somatostatinoma, a rare neuroendocrine tumor (NET), can be challenging to diagnose due to its rarity and non-specific symptoms. The differential diagnosis for somatostatinoma involves considering other functioning or nonfunctioning pancreatic neuroendocrine tumors that may present with similar clinical manifestations.

Key Points to Consider:

• Other Pancreatic NETs: Somatostatinomas need to be differentiated from other functioning or nonfunctioning pancreatic neuroendocrine tumors, such as gastrinomas, insulinomas, and VIPomas.
• Symptoms of the Somatostatinoma Syndrome: The presence of symptoms like diabetes mellitus, diarrhea/steatorrhoea, and cholelithiasis can be indicative of somatostatinoma. However, these symptoms can also be present in other conditions.
• High Somatostatin Serum Level: Elevated fasting plasma somatostatin hormone concentration (≥ 3 times the upper reference value) is a key diagnostic criterion for somatostatinoma.
• Somatostatin Immunoreactivity: The presence of somatostatin immunoreactivity in tumor cells can also support the diagnosis of somatostatinoma.

Other Conditions to Consider:

• Gastrinomas: These tumors produce gastrin, leading to peptic ulcers and diarrhea.
• Insulinomas: These tumors secrete insulin, causing hypoglycemia.
• VIPomas: These tumors produce vasoactive intestinal peptide (VIP), resulting in severe diarrhea and dehydration.

Diagnostic Approach:

To confirm the diagnosis of somatostatinoma, a tissue sample from a suspected patient with this condition should be obtained through biopsy or post-surgery. The sample should then be marked with special stains and assessed under the microscope (histology). Additionally, measuring fasting plasma somatostatin hormone concentration can help support the diagnosis.

References:

• [1] Somatostatinoma is a rare neuroendocrine tumor (NET) with an incidence of 1 in 40 million individuals[1].
• [2] The presence of symptoms of the somatostatinoma syndrome, high somatostatin serum level, and somatostatin immunoreactivity in tumor cells represent the cornerstone of the diagnosis.[11]
• [12] Somatostatinoma patients may benefit from nutritional therapies to adjust fluid, electrolyte, and glucose levels.