대한흉부영상의학회 Korean Society of Thoracic Radiology

Discussion

Diagnosis With Brief Discussion

Diagnosis

Inflammatory Myofibroblastic Tumor

Radiologic Findings

Initial chest radiograph showed an about 5cm well defined mass in the LLL. Chest CT scan revealed similar findings with chest radiograph, with obstruction of the LLL truncus basalis and distal segmental bronchi. The mass demonstrated well-defined lesion with homogenous enhancement. Neither calcifications nor cavitation in the mass. The HU of the mass in precontrast, arterial, and delayed enhancement were 39,73, and 84, repectively. Some patchy consolidation and GGO were seen with obstruction or compression of the LLL segmental bronchi, maybe due to obstructive pneumonitis. There were no significantly enlarged LNs in the mediastinum and both hilar area. In the bronchoscopy, there was well-circumscribed, oval shaped hyperemic mass in the LLL truncus basalis.

The result of the bronchoscopic biopsy was squamous metaplasia and chronic inflammation without neoplastic lesion. The mass and endobronchial lesion showed avid FDG uptake (SUVmax 20.1).

The patient underwent LLL lobectomy and diagnosis was consistent with inflammatory myofibroblastic tumor. ALK and IgG4 were both negative. On microscopic morphology, there were diffuse lymphoplasma cells and spindle cells with mild atypia.

Brief Review

Inflammatory myofibroblastic tumor (IMT) is rare among all primary lung neoplasms, accounting for only 0.04%–1.00% of them. The lung is the most common organ affected by IMT, but IMT may arise in any part of the body. It affects individuals of all ages without any sex predilection. IMT is synonymous with inflammatory pseudotumor, plasma cell granuloma, xanthogranuloma, and fibrous histiocytoma. Histopathologically, it is reported that spindle cells in the tumor commonly have low cellular atypia and no mitotic activity. Based on these histopathological features, IMT could be regarded as a low-grade malignant neoplasm. The radiologic appearance is typically that of solitary, slow-growing circumscribed mass of variable size with a lobulated or spiclulated border. Rarely, multiple multiple masses occur, and sometimes diffuse pneumonitis or atelectasis is seen, probably related to compression of a proximal bronchus. Calcification is unusual, occurring more frequently in children. Cavitation and lymphadenopathy are also rare. The radiologic differential diagnosis for IMT occurring as a solitary pulmonary nodule includes primary or secondary neoplasm, hamartoma, chondroma, hemangioma, granuloma, and pulmonary sequestration. In the PET/CT scan some articles showed more FDG uptake in the IMT than bronchial carcinoid. It is difficult to diagnose with transbronchial or transthoracic needle biopsy due to its variable cellular composition. Complete resection is recommended for both diagnosis and treatment.

References

1. Takayama Y, Yabuuchi H, Matsuo Y, Soeda H, Okafuji T, Kamitani T, Kinoshita Y, Kubokura N, Sakai S, Oda Y, Hatakenaka M, Honda H. Computed tomographic and magnetic resonance features of inflammatory myofibroblastic tumor of the lung in children. Radiat Med. 2008 Dec;26(10):613-7.
2. Ana Giménez, MD, , Tomás Franquet, MD, , Rosa Prats, MD, , Pilar Estrada, MD, , Jordi Villalba, MD, and , Silvia Bagué, MD. Unusual primary lung tumors: a radiologic-pathologic overview. Radiographics. 2002 May-Jun;22(3):601-19.
3. Lakshmana Das Narla, MD, , Beverley Newman, MD, , Stephanie S. Spottswood, MD, , Shireesha Narla, MD, and , Rajasekhar Kolli, MD. Inflammatory pseudotumor. Radiographics. 2003 Nov-Dec;23(6):1702.

Keywords

Lung, Non-infectious inflammation,