Echinococcosis differential diagnosis

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

Overview

Cystic echinococcosis must be differentiated from other diseases presenting with right sided abdominal pain such as pyogenic liver abscess and amoebic liver abscess and fungal liver abscess.

Differential Diagnosis

Echinococcal cyst must be differentiated from other diseases presenting with hepatic abscess and right sided abdominal pain such as:

Disease	Causes	Symptoms									Lab Findings	Imaging Findings	Other Findings
		Fever	Pain		Cough	Hepatomegaly	Jaundice	Weight loss	Diarrhea or Dysentry	Nausea and vomiting
			Abdominal pain (right upper quadrant pain)	Pleuritic pain
Echinococcal (hydatid) cyst	Echinococcus granulosus		✔		✔		✔ (Obstructive jaundice)	✔			Histology: Hydatid cyst with three layers: The outer pericyst: Corresponds with compressed and fibrosed liver tissue The endocyst: An inner germinal layer The ectocyst: A thin, translucent interleaved membrane	Ultrasound: Cystic to solid-appearing pseudotumors Water lily sign Calcifications seen peripherally	Blood or liquid from the ruptured cyst may be coughed up Pruritis
Amoebic liver abscess	Entamoeba histolytica	✔✔✔	✔✔✔	✔/✘	✔	✔✔/✘	✔ (late stages)	✔ (late stages)	✔	✔	Hypoalbuminemia (✔) Histology: Multiple neutrophilic abscess with areas of necrosis A rim of connective tissue, with few inflammatory cells and amoebic trophozoites	Ultrasound: Homogenous hypoechoic areas that can be single or multiple with round edges Round or oval in shape with variable size (around 2-6 cm in diameter) An incomplete rim of edema	Respond well to chemotherapy and rarely require drainage Marked male predominance More common in developing countries Sero-positive Right lobe is more frequently involved
Pyogenic liver abscess	Bacteria Gram-positive aerobes Gram-negative enterics Anaerobic organisms Acid fast bacilli	✔	✔	✔✔	✔✔	✔/✘	✔✔✔	✔ (acute loss)	Pale/dark stool	✔	Hypoalbuminemia(✔✔✔) Histology: Multiple neutrophilic abscesses with areas of necrosis in the liver parencyma	CT scan shows cluster sign Aggregation of multiple low attenuation liver lesions in a localized area to form a solitary larger abscess cavity	Abnormal pulmonary findings Diabetes mellitus increases the risk Medical-surgical approach is indicated More common in developed countries Culture positive and sero-negative Both lobes are commonly involved
Fungal liver abscess	Candida species Aspergillus species	✔	✔	✔/✘	✔	✔	✔	✔	✔	✔		CT and Us findings with four patterns of presentation: Wheel-within-a-wheel pattern Bull’s-eye configuration pattern Uniformly hypoechoic nodule Echogenic foci with variable degrees of posterior acoustic shadowing	Less common Pure fungal abscess or associated with pyogenic abscess Candida and Aspergillus are commonly found in the culture of aspirated pus Associated with underlying malignancy or DM
Malignancy (hepatocellular carcinoma/metastasis)	Hepatitis B and C Aflatoxins Alcohol Hemochromatosis Alpha 1 antitrypsin deficiency Non alcoholic fatty liver disease	✔	✔ (uncommon)			✔	✔	✔✔	Pale/Chalky stool	✔✔	High levels of AFP in serum Abnormal liver function tests	Liver biopsy	Other symptoms: Splenomegaly Variceal bleeding Ascites Spider nevi Asterixis

	Morphology	Septations	Wall character	Cyst contents
Hydatid cyst	Cyst with in cyst	-	Thick, uniform calcified	Daughter cysts
Congenital cyst	Single or multiple cysts	+/-	Thin	Low density
Cystedenoma	Single or multiple cysts	+/-	Mural nodules	Low density