Differentiating carcinoid syndrome from other diseases

Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]Associate Editor(s)-in-Chief: Parminder Dhingra, M.D. [2]

Overview

Carcinoid syndrome must be differentiated from systemic mastocytosis, medullary thyroid carcinoma, irritable bowel syndrome, malignant neoplasms of the small intestine, benign cutaneous flushing, and recurrent idiopathic anaphylaxis.

Differentiating Carcinoid Syndrome from other Diseases

Carcinoid syndrome must be differentiated from:

• Systemic mastocytosis
• Medullary thyroid carcinoma
• Irritable bowel syndrome
• Malignant neoplasms of the small intestine
• Benign cutaneous flushing
• Recurrent idiopathic anaphylaxis

On the basis [symptom 1], [symptom 2], and [symptom 3], [disease name] must be differentiated from [disease 1], [disease 2], [disease 3], [disease 4], [disease 5], and [disease 6].

Diseases		Clinical manifestations												Para-clinical findings										Gold standard	Additional findings
		Symptoms						Physical examination
														Lab Findings			Imaging						Histopathology
		Abdominal pain	Diarrhea	Flushing	Dyspnea	Palpitations	Other symptoms	Wheezing	Telangiectasia	Hypotension	Tachycardia	Systolic murmur of tricuspid regurgitation	Other physical findings	Urinary 5-hydroxyindoleacetic acid (5-HIAA)	Serum Chromogranin A (CgA)	Other markers	Abdominal computed tomography (CT)	MRI	Somatostatin receptor scintigraphy [SRS], or Octreoscan	Metaiodobenzylguanidine (MIBG) scintigraphy	Other diagnostic studies	Transthoracic echocardiography
Carcinoid Syndrome	Midgut tumours	+ Mild	+ Intermittent Secretory type	+	+	+	Pellagra Dermatitis Diarrhea Dementia	+	+	+	+			+	+	NT-proBNP Screening of carcinoid heart disease Blood Serotonin levels			+ Localization of carcinoid tumor		Positron emission tomography-computed tomography (PET-CT) using 18-fluoro-dihydroxyphenylalanine Ki-67 labeling index	Valve thickening with retraction and reduction in the mobility of the tricuspid valve		Somatostatin receptor scintigraphy [SRS], or Octreoscan	Mesenteric fibrosis Pathognomonic radiological sign of midgut NET.
	Bronchial carcinoid
Irritable Bowel Syndrome		+ Perioidic	Intermittent Chronic history of diarhea alternating with constipation	-	-	-	Associated with other conditions Fibromyalgia Chronic fatigue syndrome Gastroesophageal reflux disease, Functional dyspepsia Non-cardiac chest pain, Major depression ,Anxiety	-	-	-	-	-		-	-		-	-	-	-	Bristol stool form scale should to record stool consistency Abdominal radiograph to assess for stool accumulation and determine the severity. Age-appropriate colorectal cancer screening in all patients	-	-	Rome IV criteria recurrent abdominal pain, at least 1day/week in the last 3 months, a/s with 2 or more of the following criteria: •Related to defecation •Associated with a change in stool frequency •Associated with a change in stool form (appearance)
Malignant neoplasms of small intestine		+/-	+/-	-	-	+/-	Constipation Fatigue Early satiety	-	-	-	+/-	-	Abdominal mas Ascities	-	+		Abdominal CT scan may be diagnostic of small intestine cancer. Findings on CT scan suggestive of small intestine cancer include intrinsic mass with a short segment of bowel wall thickening	MRI and MRI enteroscopy are other advance modalities to diagnose and stage small intestinal cancers			Enteroscopy, capsule endoscopy and double balloon enteroscopy		Adenocarcinomas may be polypoid, infiltrating, or as annular constricting lesions is small intestine. Polyps and adenomas of small intestine are considered precursor lesions of adenocarcinoma. Lymphomas of small intestine present with suspicious growths in submucosa with normal appearing muscosa. Endoscopic evaluation may show multifocal involvement and large biopsies are required for diagnoses	Biopsy and histopathology
Crohn disease		Right lower quadrant pain	+/-	-	-	-							oral lesions Perianal lesions	-	-	CRP may be high					Endoscopy
Benign cutaneous flushing
Systemic mastocytosis		+	+	+	+	-	Maculopapular rash Pruritus	+/-	+/-	+	-	-	Diffuse musculoskeletal pain Neuropsychiatric symptoms	-	-	Activating mutations of KIT Serum Tryptase leevs			-	-
Recurrent idiopathic anaphylaxis
Asthma exacerbation		-	-	-	+	+		+	-	-	+	-		-	-						Chest X ray
Acute Urticaria
Anaphylaxis
Angioedema
Drugs causing flushing																									Nicotinic acid Levodopa Bromocriptine Diltiazem
Medullary Thyroid Carcinoma