대한흉부영상의학회 Korean Society of Thoracic Radiology

Discussion

Diagnosis With Brief Discussion

Diagnosis

Perivascular epithelioid cell tumors (PEComas)

Radiologic Findings

Fig 1. Chest PA shows several nodular opacities in both lungs.
Fig 2. Axial CT images reveal multiple well defined and variable sized nodules in both lungs.
Fig 3. CT images obtained 4 months later show interval increase in size of pulmonary nodules.
Fig 4. FDG PET-CT scans shows hypermetabolic activity in these nodules (SUV max, 17.26, RUL nodule)

Brief Review

Perivascular epithelioid cell tumors (PEComas) are rare mesenchymal neoplasms composed of epithelioid or spindle cells that show immunoreactivity for both smooth muscle and melanocytic markers. The lung is an uncommon location for PEC tumor, which is otherwise commonly seen in the genitourinary and gastrointestinal tracts. Pulmonary PEC tumors are usually benign and typically present as round, well-defined, peripheral nodules without cavitation or calcification. One of the characteristic imaging features is intense post-contrast enhancement, which is thought to reflect the tumor’s rich vascular stroma. It has been proposed that PEComas displaying 2 or more of the features of large size (> 5cm), infiltrative growth, high nuclear grade, mitotic activity ≥ 1/50 HPF, necrosis, or vascular invasion should be regarded as potentially malignant.

References

1. Thway K, Fisher C. PEComa: morphology and genetics of a complex tumor family. Ann Diagn Pathol. 2015;19(5):359-368.
2. Lim HJ, Lee HY, Han J, Choi YS, Lee KS. Uncommon of the uncommon: malignant perivascular epithelioid cell tumor of the lung. Korean J Radiol. 2013;14(4):692-696.
3. Folpe, A. L., & Kwiatkowski, D. J. (2010). Perivascular epithelioid cell neoplasms: pathology and pathogenesis. Human pathology, 41(1), 1-15.

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