[Intimal sarcoma of pulmonary arteries]

Clinicopathological features of pulmonary artery and vein intimal sarcomas: case series of rare pulmonary vessel intimal sarcoma

Background

Pulmonary vessel intimal sarcoma (IS) is rare.

Methods

We studied gross pathology, microscopic images and immunohistochemistry of 2 pulmonary artery ISs (PAISs) and 2 pulmonary vein ISs (PVISs), followed up the prognosis. The clinical manifestations of IS, imaging examination, electrocardiographic examination and serological examination were also studied.

Results

Grossly, the tumors were grayish yellow or grayish-white accompanied by local bleeding, and were manifested as sticky and slippery nodules. PAISs were located in the lumen of the pulmonary trunk or right ventricular outflow tract, and 1 of them had pedicle. PVISs were mainly located in the left atrium. Microscopically, the heteromorphic spindle cells were arranged in lobules and bundles, partially epithelioid, with visible mitotic figures. There were interstitial mucoid degeneration and local hemorrhage and necrosis/infarction. Immunohistochemistry showed that vimentin, h-caldesmon and MDM2 were all positive, SATB2 (+, 3/4); Ki67 proliferation rate was 30–60%; smooth muscle actin, desmin and CD56 were partially positive; cytokeratin and CD34 were locally positive; CD31, FLI-1, and ERG vascular markers were negative; and S-100 was negative. Case 4 showed MDM2 (12q15) amplification. Tumor markers were negative in venous blood; and lactate dehydrogenase increased in 2 cases. 3 patients died after surgery, 1 still survives after 14 months with lung and chest metastases for immunotherapy and 9 courses of chemotherapy.

Conclusions

IS is rare. Microscopically, it is mainly composed of spindle cells (or local epithelioid), along with interstitial mucoid degeneration. IS can differentiate into tumor of fibroblasts, bone, cartilage and smooth muscle, etc. The prognosis is poor.

Pulmonary artery intimal sarcoma - A primeval or rediscovered tumor? A report of 14 new cases with literature review

Pulmonary artery sarcomas (PAS) are rare with many being undifferentiated pleomorphic or spindle cell (UPSC) sarcomas with variable atypia. The term pulmonary artery intimal sarcoma (PAIS) was rarely coined in the early literature and sometimes used for luminal sarcomas. With the advent of immunohistochemistry and molecular genetics, many of these UPSC sarcomas were found to frequently overpress MDM2 and/or CDK4 and PDGFRA with genetic alterations in 12q12-15 and 4q12, where the MDM2, CDK4 and PDGFRA genes are located. These recent developments enabled refinement in diagnosis of PAIS. We diagnosed 14 cases of PAIS (6 males and 8 females, mean age 44 years) in 2015 - 2020 in our institution. Six were initially misdiagnosed as thromboembolism and the remaining pulmonary artery tumors. The tumors were pulmonary artery intraluminal polypoid masses with histology of spindle cell sarcomas exhibiting immunohistochemical positivity for MDM2 (100%) and CDK4 (79%) with MDM2 gene amplification (100%). Ten surgically treated patients fared better than four other biopsy only and not surgically treated patients, who died of disease within 5-11 months. PAIS needs to be differentiated from other spindle cell tumors and those exhibiting MDM2 gene amplification, especially dedifferentiated liposarcoma. The use of biopsy to provide diagnostic material poses a sampling error problem and correlation with clinical, radiologic, histologic, immunophenotypic and genotypic features are essential for accurate diagnosis and early surgical intervention of PAIS.