Long-lasting stable disease with mTOR inhibitor treatment in a patient with a perivascular epithelioid cell tumor: A case report and literature review

Abstract

Perivascular epithelioid cell tumor (PEComa) of the small intestine is extremely rare, and there is no established treatment at the present time. In 10% of patients with PEComas, genetic alterations of tuberous sclerosis complex have been reported. These genetic alterations activate mechanistic target of rapamycin (mTOR) in AMP-activated protein kinase and Ras/mitogen-activated protein kinase pathways, resulting in high mTOR activity. Since 2007, several cases of treatment with mTOR inhibitors in advanced PEComa have been reported. The current study presents the case of a patient with small bowel PEComa that metastasized to the brain and lungs. Following resection of the brain metastasis, the patient was treated with everolimus, a mTOR inhibitor, resulting in improvement if the patient's quality of life and a long period of stable disease. In conclusion, the use of mTOR inhibitors as a first-line treatment option in advanced PEComa patients appears to be reasonable, according to the increasing evidence from data observed from reported cases with this rare malignancy.

Keywords: PEComa; everolimus; literature review; mTOR inhibitor.

Figure 1.

Brain magnetic resonance imaging at the posterior fossa with contrast medium (IV gadolinium) injection in a patient with perivascular epithelioid cell tumor of the small bowel. In the left lobe of the cerebellum, a hypodense peripherally-enhanced lesion with prominent edema and mass effect is observed.

Figure 2.

Histology of the brain metastasis. The tumor is composed of packed nests of epithelioid cells with pink granular or partially clear cytoplasms (hematoxylin and eosin staining; ×100 magnification, inset ×400 magnification).

Figure 3.

(A) First slice of abdominal CT beneath the bronchus intermedius ~1 year following the diagnosis of brain metastasis. A large right hilar mass and multiple bilateral pulmonary nodules representing metastatic spread are observed. (B) Thoracic CT beneath the bronchus intermedius 2 months subsequent to the patient beginning treatment with everolimus. The right hilar mass has not altered, but the majority of the pulmonary nodules have decreased in size. No novel nodules are observed. CT, computed tomography.