[Often misdiagnosed primary pleural epithelioid hemangioendothelioma: a clinicopathological analysis of five cases].

Objective

To investigate the clinicopathological features, diagnosis and differential diagnosis of primary pleural epithelioid hemangioendothelioma (EHE).

Methods

Five cases of pleural EHE diagnosed from 2012 to 2019 in the Shanghai Pulmonary Hospital of Tongji University, China, were collected. They were subjected to review of clinical and image data, reevaluation of histological sections, immunohistochemistry study, clinical follow up and literature review.

Results

There were 1 male and 4 females (male to female ratio of 1∶4). The age ranged 19‒58 years, with a median age of 52 years. There was no smoking history in all 5 cases. Clinical manifestations included chest distress, chest pain, cough and hemoptysis. CT scan showed pleural effusion, pleural thickening, multiple pleural nodules and pneumothorax. All of the 5 cases were diagnosed based on thoracoscopic biopsies, which were performed for the suspicion of malignancy in 3 cases and for the suspicion of tuberculosis upon the failure of anti-tuberculosis treatment in 2 cases. Histologically, the tumors grew in the mesenchyme, forming cords, nests and solid sheets. The tumor cells were round, oval, short spindle, and polygonal in shape. They were epithelioid and had abundant cytoplasm and prominent nucleoli. Blister cells (vacuoles in cytoplasm) could be seen, and for mednewly-generated vessel lumen. Mucoid degeneration and collagenization were common in the tumor stroma. The positive-stainin grate was 5/5 for vimentin, 5/5 for D2-40, 4/5 for CD31, 4/5 for ERG, 4/5 for CAMTA1, 2/5 for CD34 and 2/5 for CKpan. WT1, calretinin and CK5/6 were all negative. The follow-up time ranged from 4‒18 months. During the follow-up, 4 patients were treated with chemotherapy (2 patients died, and 2 survived with tumor), and 1 patient lost to the follow-up.

Conclusions

Primary pleural EHE is rare. Its imaging and clinical features are very similar to those of tuberculosis. The correct diagnosis relies on pathological biopsy. Tumor cells are epithelioid. When CD34 is negative and D2-40 is positive, it is easy to be misdiagnosed as malignant mesothelioma. The combination of CD31, ERG and CAMTA1, which have high specificity of EHE, is helpful for the differential diagnosis.