Unraveling the spectrum of inflammatory myofibroblastic tumors in the lung: A comprehensive case series highlighting endobronchial, pleural, and lung parenchymal tumors

Abstract

Objectives: Diverse cases of inflammatory myofibroblastic tumors (IMTs) in the lung (pleural, endobronchial, and parenchymal) are presented while discussing the (preoperative) diagnostic challenges and treatment modalities. Other objectives include emphasizing the significance of gene rearrangements and highlighting the multidisciplinary approach in addressing IMTs.

Methods: Four cases of IMT in the lung are presented, including a young adolescent girl with an ETV6-neurotrophic tyrosine receptor kinase 3 (NTRK3) gene rearrangement, a 5-year-old boy with challenging preoperative diagnosis, and 2 middle-aged women with respectively pleural and endobronchial tumors with one peribronchial relapse.

Results: The cases demonstrate the diverse clinical presentations and diagnostic complexities associated with IMT in the lung. Surgical resection remains the primary treatment modality, with complete resection leading to a cure in most patients. Unfortunately, aggressive relapse can occur, as in our last case of an endobronchial tumor. Frozen section may confirm the presence of malignant cells perioperatively and impact further treatment. The presence of gene rearrangements, such as ETV6-NTRK3, suggests potential therapeutic implications.

Conclusions: Early detection and complete surgical removal of IMT are crucial for effective treatment. Identifying gene rearrangements such as ETV6-NTRK3 holds promise for targeted therapies. Diagnostic challenges, including the controversy of biopsies and preoperative evaluations, underscore the importance of a multidisciplinary approach. Anatomopathological recognition of IMT stays demanding. Close surveillance is necessary due to potential relapse, whereas frozen section perioperatively can help further treatment. This case series emphasizes the diagnostic challenges and therapeutic considerations for IMT in the lung.

Keywords: ETV6-NTRK3 gene rearrangement; inflammatory myofibroblastic tumor; peribronchial relapse; pleural inflammatory myofibroblastic tumor.

Graphical abstract

Four lung IMT cases (rare ETV6-NTRK3 fusion, uncommon pleural IMT and aggressive relapse).

Figure 1

All computed tomography, positron emission tomography–computed tomography, and/or magnetic resonance imaging of all 4 cases. PET, Positron emission tomography; CT, computed tomography; MRI, magnetic resonance imaging.

Figure 2

Hematoxylin and eosin staining of the tumor reveals spindle cells associated with a mixed chronic inflammatory infiltrate (A). ALK staining shows a low level cytoplasmatic expression (B). ALK, Anaplastic lymphoma kinase.

Figure 3

Hematoxylin and eosin staining of the tumor cells with a poorly delimited pale eosinophilic cytoplasm and elongated, monomorphic nuclei (A). ALK staining shows a diffuse positive nuclear staining (B). ALK, Anaplastic lymphoma kinase.

Figure 4

Thoracic computed tomography scan showing the bronchial tumor (arrow) starting from the lobar bronchus of the right lower lobe. Extension to the middle-lobe bronchus cannot be ruled out.

Figure 5

Four rare cases of IMT in the lung with the diagnostic and therapeutic consequences. IMT, Inflammatory myofibroblastic tumor; NTRK, neurotrophic tyrosine receptor kinase; ALK, anaplastic lymphoma kinase.

Figure 6

Overview of work-up for pulmonary IMT. pt, Patient; RT, radiotherapy; TKI, tyrosine kinase inhibitor; AE, adverse events; IMT, inflammatory myofibroblastic tumor.