Primary malignant mesothelioma of the diaphragm with liver invasion: A case report and review of literature

Abstract

Rationale: Malignant mesothelioma is a malignant tumor with poor prognosis, which usually originates in the pleura, peritoneum, and pericardial cavity. Mesotheliomas that originate from the diaphragm are very rare. Here, we report a case of primary malignant mesothelioma of the diaphragm with liver invasion.

Patient concerns: A 66-year-old woman was admitted to our hospital because of a "liver space-occupying lesion," without any special clinical symptoms. Imaging examinations suggested a cystic-solid mixed lesion in the right lobe of the liver.

Diagnosis: The tumor was diagnosed as epithelioid mesothelioma of the diaphragm with liver invasion.

Intervention: The patient underwent abdominal surgery in our hospital to remove the diaphragmatic mass, liver mass, and part of the diaphragm.

Outcomes: The postoperative course was uneventful.

Lessons: Primary diaphragmatic malignant mesothelioma is very rare and may involve liver or lung tissue and be mistaken for liver or lung tumor. Accurate diagnosis depends on careful pathological examination. Immunohistochemical staining is very useful to distinguish this tumor from other liver or diaphragmatic tumors.

Figure 1

Computed tomography imaging of the tumor. Computed tomography showed a round lesion in the right liver with relatively clear border. The lesion was about 8.2 cm × 8.2 cm × 7.3 cm, and elevated from the liver surface, closely adhering to the right diaphragm.

Figure 2

Morphological change of the tumor. (A) Epithelioid tumor cells formed microcysts, cords, or small nests. The stroma exhibited fibrosis and hyaline change (H&E staining, ×200). (B) The tumor cells were large and round or oval shape with abundant, clear cytoplasm. The nuclei were blunt, ovoid, and eccentric without nucleoli. The mitotic figures were very few (H&E staining, ×400).

Figure 3

Immunohistochemical staining of the tumor. The tumor cells were strongly positive for Wilms tumor 1 (A), cytokeratin 5/6 (B), calretinin (C), D2–40 (D), and vimentin (E) staining. (F) Ki-67 proliferative index was about 5% to 10%. (S–P method, ×200).