BACKGROUNDInflammatory myofibroblastic tumors (IMTs) are rare tumors of soft tissue recognized recently and the lung is one of common organs involved. The aim of this study is to investigate the valuable clinicopathological features for diagnosis of IMTs of the lung.

METHODSThe clinicopathology data of 9 patients with IMTs were collected. The resected lesions of the patients were studied by histological and immunohistochemical methods.

RESULTSThe 9 patients' symptoms mainly included cough, expectoration and dyspnea. Seven patients displayed as benign IMTs and 2 malignant IMTs. The big spindle neoplastic myofibroblastic cells of the benign IMTs had eosinophilic cytoplasm and round or oval nuclei. Mitoses were generally scanty (0-2/50HPF). Compared with the benign IMTs, the malignant IMTs displayed highly atypical polygonal cells with oval vesicular nuclei, prominent nucleoli and variable mitoses ( > 25/50HPF). Ganglion-like myofibroblastic cells with plasma cells, and lymphocytes invasion could be seen in all IMTs. The immunohistochemical results were: in all patients vimentin, muscle-specific actin and α-smooth muscle actin (+), p53 (-), while some patients desmin and anaplastic lymphoma kinase-1 (+).

CONCLUSIONSIMTs patients' symptoms are atypical. IMTs are composed with abundant myofibroblasts accompanied with many inflammatory cells. Surgical resection is the first choice for IMTs, complete resection leads to excellent survival for benign IMTs but not very well for malignancy.