Parasites and neuroendocrine tumors

connie dello buono

7 years ago

Carcinoid syndrome marked by symptoms of flushing and diarrhea, wheezing, right-sided congestive heart failure

Symptoms should guide laboratory testing for biochemical markers (National Comprehensive Cancer Network [NCCN], 2017)
Testing for hormones produced by NETs may include
- 5-hydroxyindoleacetic acid (5-HIAA) (urine or plasma) – for flushing
  - Metabolic product of serotonin
  - Two sequential 24-hour urine samples recommended
  - Significant elevation (10 times the upper reference limit) of urine 5-HIAA may indicate the presence of a carcinoid tumor
- Chromogranin A
  - Prognostic marker in NETs; elevated levels suggest poorer prognosis (NCCN, 2017)
- Gastrin – fasting concentrations, with individual off proton-pump inhibitors for 1 week
  - Prognostic marker in gastric tumors with hypergastrinemia syndrome
- Adrenocorticotropic hormone (ACTH)/cortisol – useful in thymic and bronchial tumors with Cushing syndrome
- Serotonin – whole blood preferred over serum
  - Highly specific for carcinoid identification
  - Not frequently used
- Neurokinin A – prognostic marker for midgut NETs

Definitive diagnosis requires biopsy and pathologist examination
Useful immunohistochemical stains may include chromogranin A, synaptophysin, and cytokeratin 8,18
For detailed descriptions, refer to ARUP’s Immunohistochemistry Stain Offerings

Computed tomography (CT)/magnetic resonance imaging (MRI)
- Abdomen and pelvis
Echocardiography
- For bronchopulmonary effects
- Evaluate valvular thickening and leaflet damage
Endoscopy
- As indicated by location (esophagogastroduodenoscopy [EGD], colonoscopy)
Other imaging as indicated
- Bronchoscopy
- CT of chest
- CT enterography or capsule endoscopy
- Endorectal MRI
- Endoscopic ultrasound
- Fluorodeoxyglucose positron emission tomography (FDG-PET)/CT and brain imaging with CT/MRI for poorly differentiated carcinomas
- MRI with gadoxetate
- Somatostatin receptor-based imaging

Flushing
- Menopause
- Alcohol abuse
- Pheochromocytoma
- Medullary carcinoma of the thyroid
- Mastocytosis
- Renal cell carcinoma
- VIPoma (vasoactive intestinal polypeptide secreting tumors)
Wheezing
- Asthma
- Chronic obstructive pulmonary disease
- Anaphylaxis
- Foreign body obstruction
- Pulmonary edema
Diarrhea
- Infections
  - Viral
  - Bacterial
  - Parasitic
- Autoimmune bowel disease
  - Inflammatory bowel disease
  - Celiac disease
- Laxative abuse
Heart valve disease
- Rheumatic heart diseases
- Endocarditis
- Cardiomyopathy
- Pulmonary hypertension