Localized multiple malignant epithelioid peritoneal mesotheliomas arising from the hepatoduodenal ligament and diaphragm: a case report

Abstract

Background: Malignant peritoneal mesothelioma is a rare aggressive tumor of the peritoneum. We report a rare case of resection of multiple localized malignant peritoneal mesotheliomas.

Case presentation: A 55-year-old Japanese woman was admitted to our hospital because liver tumors were detected by abdominal ultrasonography during a screening examination. Blood examination findings, including tumor makers, were within normal ranges. She had no evidence of exposure to asbestos. Computed tomography showed four hypervascular, round liver tumors, one in the lateral liver segment adjacent to the hepatic hilus, and the other three on the liver surface. Computed tomography angiography revealed that the tumor in the lateral segment had strong enhancement and was fed from the left gastric artery. In contrast, the other tumors showed no enhancement, and were fed from the right inferior phrenic artery. Abnormal accumulation was identified in the four tumors only with ¹⁸F-fluorodeoxyglucose positron emission tomography. It was very difficult to obtain a definitive preoperative diagnosis, but surgical resection was performed because we considered potential malignancy. Laparotomy revealed the principal site of the tumor in the lateral segment was on the hepatoduodenal ligament, and all other tumors were on the diaphragm. A left lobectomy and partial diaphragmatic resection were performed. The final pathological diagnosis was multiple malignant epithelioid mesotheliomas. Our patient has had no recurrence for 20 months postoperatively.

Conclusions: In general, malignant peritoneal mesotheliomas are classified as diffuse tumors, which are often unresectable and have a poor prognosis. However, early diagnosis and treatment, particularly with the localized type, as in our patient, could lead to long-term survival of the patient. We recommend that multiple malignant epithelioid mesotheliomas be included in the differential diagnosis for patients with subcapsular hepatic tumors.

Keywords: Angiography; Case report; Localized mesothelioma; Malignant peritoneal mesothelioma.

Fig. 1

Enhanced abdominal computed tomography showing a hypervascular tumor measuring 32-mm diameter (a, red arrow) in contact with the lateral liver segment. A 7-mm tumor in segment 4 (b, yellow arrow), 15-mm tumor in segment 8 (c, green arrow), and 17-mm tumor in segment 7 (d, blue arrow) are also seen. All tumors are positioned on the liver periphery. Moreover, the tumor in segment 7 is continuous with the diaphragm and has the same high density of contrast medium (white arrows)

Fig. 2

Magnetic resonance images showing a tumor with lower intensity compared with the liver on T1-weighted images (a, red arrowhead), and with higher intensity than the liver on T2-weighted and diffusion-weighted images (b and c, red arrowhead)

Fig. 3

Computed tomography (CT) during arterial portography showed enhancement in none of the tumors (a, b), but CT during hepatic arteriography revealed strong enhancement in the tumor in the lateral segment. In contrast, the remaining three tumors showed no enhancement (c, d) (red arrow, the tumor in the lateral segment; blue arrow, the tumor in segment 7; green arrow, the tumor in the in segment 8)

Fig. 4

Fluorodeoxyglucose-positron emission tomography showing increased fluorodeoxyglucose uptake (red arrow, lateral segment; yellow arrow, segment 4; green arrow, segment 8; blue arrow: segment 7)

Fig. 5

Operative findings showing one tumor located between the liver and hepatorenal ligament (a; red arrow) three other tumors located on the diaphragm (b; green and yellow arrow, c; blue arrow)

Fig. 6

On gross examination, the tumor resected by left lobectomy measures 3.6 cm in diameter, and the surface and demarcation between the tumor and liver are smooth

Fig. 7

Histopathological findings showing that tumor cells increased in a papillary form containing an epithelial pattern (a, original magnification × 30; b, original magnification × 100; all, hematoxylin and eosin stain). Tumor cells stained positively for CD31 (c), CD34 (d), D2-40 (e), and calretinin (f), and negatively for p53 (g). The Ki-67 labeling index was < 20% (h) (c–h, original magnification × 100)