대한흉부영상의학회 Korean Society of Thoracic Radiology

Discussion

Diagnosis With Brief Discussion

Diagnosis

PEComa (Perivascular epithelioid cell tumor)

Radiologic Findings

Fig 1-2. PA and lateral chest radiographs show a mass in the right mid lung zone.
Fig 3-5. Contrast-enhanced chest CT scans show a heterogeneously high-attenuation, well-defined, lentiform-shaped mass in the right interlobar fissure.
Fig 6. PET/CT did not show significant hypermetabolism.
Fig 7. The mass has grown over the past 6 years.

Brief Review

Pulmonary perivascular epithelioid cell neoplasms (PEComas) comprise a spectrum of entities, from usually benign clear cell tumors of the lung (CCTL) to rare malignant pulmonary PEComas. Because of their rarity, current knowledge is largely derived from individual case reports and small case series.

On chest CT, it typically appears as a well-circumscribed, round or oval peripheral pulmonary nodule with smooth margins. These tumors are more frequently located in the lower lobes and generally lack cavitation or calcification. Contrast-enhanced CT findings vary, but intense and heterogeneous enhancement during the arterial phase has been described, sometimes becoming more homogeneous or demonstrating washout on delayed images. Despite these features, no radiologic finding is specific enough to allow a confident diagnosis without histopathologic confirmation.

Information on PET/CT findings in pulmonary PEComa is limited. Increased FDG uptake has been reported in at least one case of malignant pulmonary PEComa, indicating hypermetabolic activity.

Surgical resection is the mainstay of treatment for pulmonary PEComa. CCTL generally shows a favorable outcome after complete excision. In contrast, malignant pulmonary PEComa follows an aggressive clinical course. Early local recurrence and distant metastases have been reported even after complete surgical resection, and rapid disease progression leading to death has been documented despite additional systemic therapy.

References

1. Liang W, Xu S, Chen F. Malignant perivascular epithelioid cell neoplasm of the mediastinum and the lung: one case report. Medicine (Baltimore). 2015;94(22):e904. doi:10.1097/MD.0000000000000904
2. Wang GX, Zhang D, Diao XW, Wen L. Clear cell tumor of the lung: a case report and literature review. World J Surg Oncol. 2013;11:247. Published 2013 Oct 1. doi:10.1186/1477-7819-11-247

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