Undifferentiated Embryonal Sarcoma of the Liver: An Enigma of Diagnosis

A 20-year-old man presented with peritonitis requiring emergency laparotomy. He was found to have a huge liver abscess on the right lobe. Open drainage was performed but the abscess was persistently unresolved upon follow up. Computed tomography (CT) revealed a solid liver lesion with raised Ca 19-9. Right hepatectomy was subjected and histology was consistent with a rare and aggressive case of embryonal sarcoma of the liver. Despite oncologic resection, he developed local recurrence and succumbed to death in 6 month postoperatively. We describe a unique aetiology of liver abscess with literature reviews of undifferentiated embryonal sarcoma of the liver.


INTRODUCTION
Undifferentiated embryonal sarcoma of the liver (UESL) is an uncommon but extremely malignant neoplasm which usually involves children between 6 to 10 years old (1).Most of these liver malignancies are carcinoma with primary hepatic sarcomas seen only in 0.1 to 2% (2).UESL was firstly described by Stocker and Ishak in 1978 (3).This tumour is categorized as a solid hepatic tumour and rarely presents as a cystic liver tumour (3).The diagnosis is an enigma due to its unspecific and rare presentations.The presentations in adults mimic any other acute abdomen.In view of its predilection in children, its condition in adults poses much more challenges.Herein, we describe a unique presentation of liver abscess that was confirmed as an undifferentiated embryonal sarcoma after hepatectomy.

CASE REPORT
A healthy Malay man presented at a periphery healthcare facility with right hypochondrium pain which was dull aching and associated with nausea, intermittent vomiting and fever.The symptoms were progressively worsening for one week duration.He was hemodynamically stable however physical examination revealed tenderness and board-like rigidity at the upper abdomen.Blood investigation showed an elevated white cell and derangement of liver function test.Fluid resuscitation and antibiotic were initiated.He underwent emergency exploratory laparotomy and intraoperatively revealed a huge liver abscess which occupied within the right lobe of liver.An open drainage was performed and drain inserted.
There was no improvement in his clinical status with continuous drainage of 50-100 mL/day.However, the abscess culture and sensitivity were negative.He was referred to our institution after ultrasonography showed none resolution of the abscess.
He was clinically and hemodynamically stable, afebrile with drain in situ containing old blood.White blood cell and C-reactive protein were remarkably raised.Hepatitis bloods screening were negative.The tumour marker, serum CA 19-9 was elevated 1508 (normal value: 0-37 U/mL) with normal serum alpha fetoprotein.Computed tomography (CT) of the abdomen showed a liver lesion occupying right side of the liver size 19 x 12.8 x 9.7 cm with presence of area of necrosis within (Figure 1A, 1B).A provisional diagnosis of cholangiocarcinoma was made based on the correlation between CT tumour markers.A liver biopsy was performed in view of indefinite diagnosis and non-resolving abscess.The liver biopsy suggested a possibility of plasmacytoma which necessitate an extended right hepatectomy.A huge solid-cystic liver mass with vascular invasion and necrotic lymph node was found intraoperatively.Macroscopic examination showed a large, well circumscribed tumor measuring 18 x 18 x 7 cm.There was presence of central necrosis and hemorrhagic solid whitish material at its periphery (Figure 2).Sheets of malignant infiltrations were seen within liver parenchyma which was separated from the surrounding tissue by a dense sclerotic band.There was also presence of irregular hyperchromatic and vesicular nuclei.Microscopic examination also showed eosinophilic cytoplasm and intracytoplasmic eosinophilic globules.These cellular components are positive for PAS and diastase.(Figure 3A).The malignant cells were positive for CD56, CD10 and desmin (Figure 3B).

Figure 1 :
Figure 1: (A) Computed tomography scan (axial view) of the liver lesion shows a well encapsulated semi-solid mass (black arrow).(B) Computed tomography scan (coronal view) shows a suspected liver abscess (black arrow).

Figure 2 :
Figure 2: Macroscopic view of the liver lesion shows a solid with cystic components with variable degree of necrosis and haemorrhage.

Figure 3 :
Figure 3: (A) Microscopic features show round to spindle shape cells (white arrow) with hyperchromatic to vesicular nuclei, moderate eosinophilic cytoplasm with indistinct borders.(Hematoxylin & Eosin x20).(B) Presence of intracytoplasmic eosinophilic globules which are positive for PAS (white arrow) (large box) and desmin (small box).