Malignant Pigmented Mass "Sequestrated" in the Lung: A Unique Case Report

Area of Science:

• Pulmonology
• Oncology
• Pathology

Background:

• Primary lung tumors within pulmonary sequestrations are exceptionally rare, typically presenting as common histologic types.
• Malignant perivascular epithelioid cell (PEComa) tumors, especially those with melanin deposition, have not been previously documented in the lung.

Observation:

• A 34-year-old male presented with recurrent hemoptysis and a left lower lobe pulmonary mass on CT scan.
• The mass showed aberrant vascularization from the left diaphragmatic artery, indicative of a potential sequestration.

Findings:

• Surgical resection revealed a malignant PEComatous tumor with TFE3 expression and a high mitotic rate.
• The tumor was found to have arisen within the context of an extralobar pulmonary sequestration.

Implications:

• This case represents the first documented instance of a malignant PEComa with melanin pigment in the lung.
• Highlights the importance of considering rare tumor types and congenital anomalies in pulmonary mass diagnosis.
• Contributes to the understanding of PEComa tumorigenesis in unique anatomical locations.