SESSION TITLE: Cancer Global Case Reports
SESSION TYPE: Global Case Report
PRESENTED ON: Tuesday, October 28, 2014 at 01:30 PM - 02:30 PM
INTRODUCTION: Inflammatory myofibroblastic tumor (IMT) of the lung, also known as plasma cell granuloma, is a rare diagnosis in adults, accounting for less than 1 % of all lung tumors. They often present as pulmonary nodules but can also be locally invasive. Although its exact origin is unknown, recent studies favor a true neoplasm rather than an inflammatory process. Diverse and non-specific clinical and radiologic manifestations make the diagnosis difficult. In most cases, surgical resection is needed for diagnosis.
CASE PRESENTATION: A 78-year- old asymptomatic female former smoker underwent shoulder arthroplasty. A postoperative chest x-ray showed a right pulmonary nodule. Computerized tomography (CT) confirmed the presence of a 1.3 x 1.2 cm well circumscribed pulmonary nodule. Image-guided biopsy was nondiagnostic. Positron emission tomography (PET) showed hypermetabolic activity of the lesion. In the clinical setting suspicious for stage IA lung cancer, she underwent an uneventful robotic assisted right middle lobe lobectomy with mediastinal lymphadenectomy. Final pathology showed a well-circumscribed nodule composed of spindle cells admixed with lymphomononuclear infiltrate with scattered atypical cells, consistent with an inflammatory myofibroblastic tumor.
DISCUSSION: Discussion: Inflammatory myofibroblastic tumor is defined by the World Health Organization as a myofibroblastic spindle cell soft tissue tumor with infiltrative plasma cells, lymphocytes, and eosinophils. It can occur in any age group but more common in pediatrics. There are no gender, ethnicity, or geographical preferences. Although half of patients are asymptomatic, symptoms may include dyspnea, cough, chest tightness, and hemoptysis. The majority of cases are diagnosed via surgical lung biopsy. The pathogenesis of IMT is unclear and several hypotheses have been proposed such as recurrent respiratory infections or auto-immune mechanisms. In more than 50% chromosomal rearrangement at band 2p23 has been observed, the site of the anaplastic lymphoma kinase (ALK). ALK is mainly positive in extrapulmonary cases. Treatment of choice is complete resection and there is no need for chemotherapy with resection. Incomplete resection or size more than 3 cm increases risk of recurrence. The differential diagnosis includes fibrosarcoma, leiomyoma, malignant fibrosis histiocytoma, lymphoma, organizing pneumonia, desmoid fibromatosis and angiomyofibroblastoma.
CONCLUSIONS: Inflammatory myofibroblastic tumor is a rare tumor in adults usually diagnosed at surgical resection. Only histological and immunohistochemical studies can confirm diagnosis due to variable and non-specific clinical and radiologic presentations. Complete surgical resection has a favorable outcome.
Reference #1: Inflammatory pseudotumor of the lung in adults. Melloni G,et al. Ann Thorac Surg. 2005 Feb;79(2):426-32. PMID: 15680808
Reference #2: Inflammatory myofibroblastic tumor of the aortic valves causing sudden cardiac death: a case report and review of the literature. . Xu B1 et al. Pediatr Dev Pathol. 2014 Mar 20.
Reference #3: A rare tumor of the lung: inflammatory myofibroblastic tumor. Hammas N et al, Diagn Pathol. 2012 Jul 17;7:83. doi: 10.1186/1746-1596-7-83. PMID: 22805416
DISCLOSURE: The following authors have nothing to disclose: Ali Rad, Michael Reed, Christopher Gilbert, Negar Rassaei, Jennifer Toth
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