Objective: Inflammatory myofibroblastic tumor (IMT) is a rare disease that usually occurs in the lung. Recently, several reports have suggested that IMT is a true neoplasm rather than a reactive lesion. In this retrospective study, we reviewed clinicopathological characteristics and prognoses for all patients with surgically resected IMT of the lung at our institute. Methods: From January 1985 to December 2002, nine patients had surgical intervention for IMT of the lung at the National Cancer Center Hospital, Tokyo. The resected lesions were studied histologically, immunohistochemically, and ultrastructurally. Follow-up was complete in all patients and varied from 3 months to 16 years 2 months (median, 6 years 2 months). Results: These nine patients included five men and four women. They ranged in age from 25 to 66 years. Seven patients were asymptomatic. The two symptomatic patients had problems including cough, hemoptysis, and dyspnea. For all these patients, the diagnostic procedure was surgical excision. The resected tumor size ranged from 1.0 to 4.0 cm in diameter. Histologically, a variety of inflammatory and spindle cells were observed. The spindle cells corresponded ultrastructurally to myofibroblasts or fibroblasts. With the exception of one patient who had spontaneous resolution of a recurrent tumor, there was no recurrence in these patients, and all of them are in good health. Conclusions: Histopathologically, IMT is characterized by myofibroblasts that are mixed with chronic inflammatory cells, including plasma cells, lymphocytes, and histiocytes. Surgical resection, when possible, can be chosen as the treatment. Complete resection leads to excellent survival.
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