Spontaneous Regression of a Pulmonary Inflammatory Myofibroblastic Tumor

Abstract

Inflammatory myofibroblastic tumors are rare benign mesenchymal neoplasms composed of myofibroblastic cells intermixed with an inflammatory infiltrate of cells including plasma cells, lymphocytes, and histiocytes. These tumors are commonly seen in children and are rare in adults. Management of these tumors is challenging due to their unpredictable behavior. Here, we present a rare case of a pulmonary inflammatory myofibroblastic tumor that regressed spontaneously following a minimally invasive computed tomography-guided percutaneous lung biopsy.

Case Details

Disease Location

Lung

Personal Characteristics

67-year-old male patient. Past medical history of hyperlipidemia and a family history of coronary artery disease. Smoking history spanning two years when he was younger

Clinical Characteristics

Calcium-scoring CT of the chest, incidentally revealed fibrotic and reticular changes in bilateral lower lobes, along with small subcentimeter pulmonary nodules in both upper lobes. A follow-up dedicated CT of the chest, performed six months after the initial scan, revealed a new mass measuring 3.2 cm x 2.1 cm at the lateral aspect of the right pulmonary apex, contiguous with adjacent thickened pleura with reticulonodular and fibrotic changes in bilateral lower lobes. CT-guided percutaneous lung biopsy revealed a benign spindle cell mesenchymal process with scattered lymphocytes, plasma cells, and eosinophils consistent with an inflammatory myofibroblastic tumor (imt). Immunostaining was diffusely positive for vimentin and smooth muscle actin

Remission Characteristics

Follow-up CT of the chest six months after lung biopsy revealed regression of the lesion, with only chronic scarring observed from the prior lung biopsy

Treatment & Mechanisms

Proposed Remission Mechanisms

The plasma cell variant may have a better prognosis and potential for spontaneous regression

Clinical Treatment

Biopsy