Primary Hemangiopericytoma Arising in Extralobar Pulmonary Sequestration: A Coincidence or Two Rare Disorders?

Abstract

Background/aim: Extralobar pulmonary sequestration (EPS) is an unusual congenital defect characterized by the presence of non-functioning lung tissue receiving arterial supply from the systemic arteries. Primary hemangiopericytoma (HPC) is an uncommon potentially malignant tumor of vascular origin that usually involves the soft tissue of the extremities or retroperitoneum, but extremely rarely affects the lung. We present the rare case of a primary pulmonary HPC arising in an EPS.

Case report: A 65-year-old woman, with dyspnea and pleuritic chest pain, was referred for further investigation. Radiological evaluation demonstrated a well-circumscribed mass above the right hemidiaphragm, receiving its arterial supply from the descending thoracic aorta. The patient underwent a right posterolateral thoracotomy and a middle lobectomy. The intraoperative finding was a well-encapsulated solid mass. The histological evaluation described HPC.

Results: The patient remains fit and healthy.

Conclusion: Pulmonary HPC can arise in EPS. Surgical excision is the treatment of choice.

Keywords: Hemangiopericytoma; extralobar; pulmonary; sequestration.

Figure 1. Contrast-enhanced computed tomography (CT) and CT angiography findings of extralobar pulmonary sequestration (EPS). A: A wellcircumscribed mass just above the right hemidiaphragm and a small ipsilateral pleural effusion were depicted by thoracic CT. B: CT angiography confirmed the presence of a solid soft-tissue mass causing local atelectasis of the adjacent lung. C, D: The lesion had a systemic arterial blood supply consisting of small-sized feeding vessels and larger arterial branches which originated from the subdiaphragmatic segment of the abdominal aorta (coronal reconstructed maximum intensity projection). All the above findings were consistent with a diagnosis of EPS.

Figure 2. The patient underwent right posterolateral thoracotomy. A sizeable well-encapsulated solid mass was successfully detached from surrounding tissues.

Figure 3. Histological examination of the solid soft-tissue mass resected from the right lower lung lobe. The tumor had a perivascular hemangiopericytomatoid pattern of cellular growth, and vessel dilatation was also observed in eosin-hematoxylin images (100×) (A). Tumor cells were strongly and diffusely positive for vimentin (B), CD34 (C): and CD99 (D) (200×).