Correlations between MDCT features and clinicopathological findings of hepatic paragonimiasis. Eur J Radiol. 2012;81:e421-e425. [PMID: 21440394 DOI: 10.1016/j.ejrad.2011.03.019]

Paragonimiasis

Paragonimiasis is a zoonotic disease caused by lung flukes of the genus Paragonimus. Humans usually become infected by eating freshwater crabs or crayfish containing encysted metacercariae of these worms. However, an alternative route of infection exists: ingestion of raw meat from a mammalian paratenic host. Adult worms normally occur in pairs in cysts in the lungs from which they void their eggs via air passages. The pulmonary form is typical in cases of human infection due to P. westermani, P. heterotremus, and a few other species. Worms may occupy other sites in the body, notably the brain, but lung flukes have made their presence felt in almost every organ. Ectopic paragonimiasis is particularly common when infection is due to members of the P. skrjabini complex. Human paragonimiasis occurs primarily in the tropics and subtropics of Asia, Africa, and the Americas, with different species being responsible in different areas (Table 6.1).

Thoughts underlying "pneumonia" resulting from eating: A case report

As a rare zoonotic helminth disease, paragonimiasis is easy to be misdiagnosed. Adequate attention to the medical history of the patient and early detection of serological antibodies can improve the diagnosis rate. Praziquantel and trichlorobendazole are commonly used for treatment, and the prognosis is good. This case report mainly introduces the classification, diagnosis, and treatment of paragonimiasis, with an aim to draw the attention of doctors to the disease.

A case of hepatic paragonimiasis was misdiagnosed as hepatocellular carcinoma with rupture and haemorrhage

Paragonimiasis is a disease caused by parasitic infections that mainly involve the lungs. However, it can also produce ectopic infections, such as when the parasites invade the liver, brain and subcutaneous tissue, which then cause different symptoms. This current case report describes a 55-year-old male patient with hepatic paragonimiasis that was misdiagnosed as liver cancer with rupture and haemorrhage. The initial computed tomography findings suggested ruptured liver cancer. The patient underwent laparoscopic right hemihepatectomy. Postoperative pathological analysis resulted in a diagnosis of hepatic paragonimiasis. The patient recovered well postoperatively and was treated with 25 mg/kg praziquantel orally three times a day for 3 days after discharge with good efficacy. In this present case, the rupture and haemorrhage of the liver mass made it difficult for the treating physicians to consider hepatic paragonimiasis, which lead to the initial misdiagnosis of this patient. Although paragonimiasis is very rare, medical staff should be vigilant and have a comprehensive understanding of the different diseases that can cause liver masses so that misdiagnosis can be avoided.

Paragonimiasis

Paragonimiasis is a zoonotic disease caused by lung flukes of the genus Paragonimus. Humans usually become infected by eating freshwater crabs or crayfish containing encysted metacercariae of these worms. However, an alternative route of infection exists: ingestion of raw meat from a mammalian paratenic host. Adult worms normally occur in pairs in cysts in the lungs from which they void their eggs via air passages. The pulmonary form is typical in cases of human infection due to P. westermani, P. heterotremus, and a few other species (Table 5.1). Worms may occupy other sites in the body, notably the brain, but lung flukes have made their presence felt in almost every organ. Ectopic paragonimiasis is particularly common when infection is due to members of the P. skrjabini complex (Table 5.1). Human paragonimiasis occurs primarily in the tropics and subtropics of Asia, Africa, and the Americas, with different species being responsible in different areas (Table 5.1).

Distinct MDCT imaging features to differential diagnosis of hepatic paragonimiasis and small hepatocellular carcinoma

We used multi-row detector computed tomography (MDCT) to identify the distinguishing characteristics of hepatic paragonimiasis and small hepatocellular carcinoma lesions. We analyzed a cohort of 60 patients, of which 26 had hepatic paragonimiasis and 34 with a small (≤ 3cm) hepatocellular carcinoma. MDCT detected 65 lesions that were retrospectively reviewed and analyzed based on their imaging features. Both groups showed distinct MDCT imaging features that could contribute to an accurate diagnosis. In the paragonimiasis group, 75% (21/28) lesions were located in the hepatic subcapsular region, whereas only 10.8% (4/37) of lesions in the hepatocellular carcinoma group were subcapsular. Most hepatic paragonimiasis lesions (57.1%; 16/28) also showed characteristic tubular or tunnel features that were not present in hepatocellular carcinomas. Further, 71.4% (20/28) paragonimiasis lesions were rim enhanced with irregular tract-like non-enhanced internal areas with a characteristic target loop, while 94.6% (35/37) of small hepatocellular carcinoma lesions showed homogenous enhancement in the arterial and venous phase. In addition, the period CT values for hepatic paragonimiasis were less than those of hepatic carcinomas (P<0.001). These clinically significant findings illustrate the diagnostic features that enable one to distinguish hepatic paragonimiasis from small hepatocellular carcinomas.

Hepatic paragonimiasis in a 15-month-old girl: a case report

Background

Paragonimiasis, particularly hepatic paragonimiasis (HP), is a type of zoonotic parasitic disease rarely encountered in infants. There have been only a few reports of HP, and no case of HP has been reported in an infant.

Case presentation

A 15-month-old girl presented with persistent mild fever with a duration of 1 month, hepatomegaly, and low-density lesions in the right hepatic lobe on abdominal ultrasound and computer tomography. Pathological examination and serum antibody detection were performed to verify HP. The diagnosis of HP was established based on findings of Charcot-Leyden crystals on liver lesion biopsy and antibodies against paragonimus westermani detected by enzyme-linked immunosorbent assay. After initiation of praziquantel (75 mg/kg/day for 3 days), all clinical findings promptly improved and the patient was discharged.

Conclusion

It is very important to consider paragonimiasis in the clinical examination of infants from an area with paragonimiasis epidemic presenting with fever, hepatomegaly, low-density lesions in the liver.

Hepatic paragonimiasis: a single-center retrospective analysis of 32 cases in Mainland China

Background

In paragonimiasis, the lungs and pleural cavity are the major target organs, and the central nervous system can also be affected. The liver is an organ in which ectopic paragonimiasis rarely occurs. Because the symptoms and examinations in hepatic paragonimiasis (HP) are not typical, the disease is often misdiagnosed in the clinic.

Methods

From February 2008 to March 2015, our department accepted 32 patients who presented with a liver mass upon ultrasound and computed tomography imaging and in whom the source of the mass could not be identified upon numerous further diagnostic tests. We ultimately obtained surgical biopsies of their lesions for pathological examination. We analysed the clinical data of these cases, along with their disease characteristics, the diagnostic strategies employed and their treatment experiences. Additionally, we performed patient follow-up for a period of 6–12 months.

Results

All patients underwent half/partial hepatectomy and were diagnosed with HP upon pathological examination. They recovered well after surgery and their original symptoms were markedly improved without recurrence. The liver functions of the patients reached normal levels before discharge and no additional liver lesions were found upon diagnostic imaging.

Conclusion

The diagnosis of HP based on clinical manifestations, laboratory tests or image examination is difficult and only pathologic analysis of biopsies could confirm HP. Surgical treatment not only removes lesions, but also allows for pathologic biopsy. This study encompasses the largest number of HP patients to date, but the surgical outcomes require further research and long-term follow-up.

A Case of Ectopic Paragonimiasis in a 17th Century Korean Mummy

Archaeoparasitological studies on fossilized feces obtained from Joseon Dynasty (1392-1910 CE) mummies have provided invaluable data on the patterns of parasitic infection in pre-modern Korean societies. In our recent radiological investigation of a 17th century Joseon mummy discovered in Cheongdo (South Korea), we located a liver mass just below the diaphragm. Anatomical dissection confirmed the presence of a mass of unknown etiology. A subsequent parasitological examination of a sample of the mass revealed a large number of ancient Paragonimus sp. eggs, making the current report the first archaeoparasitological case of liver abscess caused by ectopic paragonimiasis.

Feasibility of laparoscopic major hepatectomy for hepatic paragonimiasis: two case reports

BACKGROUND

Though accumulated evidence proved that laparoscopic major hepatectomy was technically feasible, it remains a challenging procedure and is limited to highly specialized centers. Paragonimiasis is one of the most important food-borne parasitic zoonoses caused by the trematode of the genus Paragonimus. Although hepatic paragonimiasis is rare, the previous studies had investigated hepatic paragonimiasis from different perspectives. However, the safety and feasibility of laparoscopic major hepatectomy for hepatic paragonimiasis have not yet been reported in the literature.

METHODS

We here present 2 cases of hepatic paragonimiasis at the deep parts of the liver with treatment by laparoscopic major hepatectomy. One case is a 32-year-old male patient who was admitted to the hospital due to upper abdominal discomfort without fever for 1 month. The clinical imaging revealed that there was a lesion about 5.9 × 3.7 cm in the boundary of right anterior lobe and right posterior lobe of the liver with rim enhancement and tract-like nonenhanced areas. The other one is a 62-year-old female patient who was referred to the hospital for 1 month of right upper abdominal pain and fever. The ultrasonography showed that there was a huge hypoechoic mass (about 10.8 × 6.3 cm) in middle lobe of the liver with tract-like nonenhanced areas. Both patients were from an endemic area of paragonimiasis and the proportion of eosinophil in the second case was increased.

RESULTS

The preoperative diagnosis of the first case was ambiguous and the hepatic paragonimiasis was considered for the second case. The first case underwent laparoscopic extended right posterior lobe hepatectomy and the other case underwent laparoscopic extended left hemihepatectomy. Both operations went very well and the operation times for the 2 cases were 275 minutes and 310 minutes, respectively. The 2 patients' postoperative recovery was smooth without major postoperative complications (such as, bleeding, bile leakage, and liver failure). Moreover, the 2 patients were discharged on the 6th day and 7th day after surgery, respectively. The postoperative histopathological examination manifested hepatic paragonimiasis in both patients.

CONCLUSION

This study suggests that the laparoscopic approach may be safe and technically feasible for hepatic paragonimiasis.

Paragonimiasis

Paragonimiasis is a zoonotic disease caused by lung flukes of the genus Paragonimus. Humans usually become infected by eating freshwater crabs or crayfish containing encysted metacercariae of these worms. However, an alternative route of infection exists: ingestion of raw meat from a mammalian paratenic host. Adult worms normally occur in pairs in cysts in the lungs from which they void their eggs via air passages. The pulmonary form is typical in cases of human infection due to P. westermani, P. heterotremus, and a few other species (Table 5.1). Worms may occupy other sites in the body, notably the brain, but lung flukes have made their presence felt in almost every organ. Ectopic paragonimiasis is particularly common when infection is due to members of the P. skrjabini complex (Table 5.1). Human paragonimiasis occurs primarily in the tropics and subtropics of Asia, Africa, and the Americas, with different species being responsible in different areas (Table 5.1).

Contrast-enhanced ultrasonographic findings of hepatic paragonimiasis

AIM: To investigate the features of hepatic paragonimiasis on contrast-enhanced ultrasound (CEUS) imaging.

METHODS: Fifteen patients with hepatic paragonimiasis who were admitted to our hospital between March 2008 and August 2012 were enrolled to this study. The conventional ultrasound and CEUS examinations were performed with a Philips IU22 scanner with a 1-5-MHz convex transducer. After conventional ultrasound scanning was completed, the CEUS study was performed. Pulse inversion harmonic imaging was used for CEUS. A bolus injection of 2.4 mL of a sulfur hexafluoride-filled microbubble contrast agent (SonoVue) was administered. CEUS features were retrospectively reviewed and correlated with pathological findings.

RESULTS: In total, 16 lesions were detected on CEUS. The mean size of the lesions was 4.4 ± 1.6 cm (range, 1.7-6.6 cm). Subcapsular location was found in 12 lesions (75%). All the lesions were hypoechoic. Six lesions (37.5%) were of mixed content, seven (43.8%) were solid with small cystic areas, and the other three (18.8%) were completely solid. Ten lesions (62.5%) were rim enhanced with irregular tract-like nonenhanced internal areas. Transient wedge-shaped hyperenhancement of the surrounding liver parenchyma was seen in seven lesions (43.8%). Areas with hyper- or iso-enhancement in the arterial phase showed contrast wash-out and appeared hypoenhanced in the late phase. The main pathological findings included: (1) coagulative or liquefactive necrosis within the lesion, infiltration of a large number of eosinophils with the formation of chronic eosinophilic abscesses and sporadic distribution of Charcot-Leyden crystals; and (2) hyperplasia of granulomatous and fibrous tissue around the lesion.

CONCLUSION: Subcapsular location, hypoechogenicity, rim enhancement and tract-like nonenhanced areas could be seen as the main CEUS features of hepatic paragonimiasis.