Inflammatory myofibroblastic tumor is a rare soft tissue tumor. It can bediscovered in many organs but is most commonly found in the lung.1,2Gold standard of diagnosis is tissue biopsy. Computed tomography (CT)and Positron emission tomography/computed tomography (PET/CT) has arole in diagnosis but sensitivity and specificity is not very high.3,4 Presentationmay vary widely from single pulmonary nodule, endobronchial lesion,bilateral lung nodule or distant metastasis.2-11 Mainstay of treatment iscomplete resection which has a better survival rate and lower recurrence rate.Video-assisted thoracoscopic surgery (VATS) resection is one of the safestand most effective ways to treat the patient.9,11 In cases of endobronchiallesion, palliative endobronchial resection is utilized to restore patient’sairway.6,10
A 42-year-old Arabic male previously healthy presented with asymptomaticsingle pulmonary mass found from annual check-up chest x-ray. CT of Chestrevealed 3.9 cm right upper lobe pulmonary mass with compression toposterior segmental bronchus of right upper lobe with possible right middlelobe invasion as shown in Figure 1A and 1B. Bronchoscopy with biopsy wasdiscussed with the patient. He decided to proceed with surgical biopsy andresection given the concern of the progression of airway compression.
General anesthesia was performed by left sided double lumen tube.Uniportal VATS exploration revealed right upper lobe mass bulging out frompulmonary parenchyma with complete minor fissure as shown in Figure 1C.Given the proximity of the tumor to the main RUL bronchus, right upperlobe (RUL) lobectomy was undertaken through the same 4 cm uniportalincision. Frozen section showed spindle cell tumor with free bronchial andstaple margin. The postoperative course was uneventful and the patient wasdischarged on postoperative day 1. One month postoperative chest x-rayshowed full lung expansion without residual space as shown in Figure 1D.Final pathology demonstrated inflammatory myofibroblastic tumor as provenby positive anaplastic lymphoma kinase (ALK) and smooth muscle actin andnegative for CD34. All 2R, 4R, 7, 9 lymph node stations tested negative fortumor as shown in Figures 1E to 1H.
Figure 1A: shows chest x-ray, preoperative.
Figure 1B: CT chest, axial view shows central masscompressing apical segment of right upper lobe.
Figure 1C: Shows a bulging mass protrudingunder the intact visceral pleura.
Figure 1D: Shows good lung reexpansion onpostoperative day 1.
Figure 1E: Cut surfaces of the mass reveals asolid, well demarcated grey-yellow mass withoutnecrosis.
Figure 1F: Shows plump spindle cell tumorarranging in intersecting fascicles and storiformpattern with additional lymphoplasma cellinfiltration.
Figure 1G: The tumor cells shows irregularimmunohistochemical reaction for smooth actin.
Figure 1H: Strongly and diffusely immunohistochemical reaction for ALK is in the tumor cells.
A 30-year-old Arabic previously healthy male presentedwith massive hemoptysis initially treated by a local hospitalin his country and was found to have a bleeding RULendobronchial mass. Chest x-ray revealed multiple bilateralpulmonary masses with endobronchial lesions, largest (6 cm)at right upper lobe as shown in Figures 2A-B. Completeresection is not possible due to insufficient pulmonary reserve.Biopsy demonstrated spindle cell proliferation with storiformand fascicular architectures with spindle cells stained diffuselyfor smooth muscle actin and focally desmin and caldesmon.Staining for cytokeratins, CD34, ALK, and ROS1. Theconclusion was inflammatory myofibroblastic tumor givennegative ALK and ROS1 are not positive in all adult cases. Hewas transferred to Bangkok Hospital Headquarters. Flexiblebronchoscopy by pulmonologist revealed mild bleeding ofendobronchial mass at right upper lobe bronchus withextension into right main bronchus causing near totalocclusion. Rigid bronchoscope was introduced and tumor wascored out in right main bronchus as well as right upper lobebronchus then bleeding was controlled by argon plasmacoagulation as shown in Figure 2C. Pathology demonstratedinflammatory myofibroblastic tumor proven by diffuselypositive smooth muscle actin, as shown in Figure 2D.Remaining intrapulmonary tumor was destroyed by microwaveablation in right upper, right lower and left lower lobe.Repeated flexible bronchoscopy was commenced 1 month laterdemonstrating the patency of right main and right upper lobebronchi. On 6-month follow-up, he was found to have tumormetastasis at soft tissue area around left biceps muscle. Givenno symptom of hemoptysis, we continued to follow-up withoutintervention. He continued to be symptom-free on 18 monthsfollow-up with small progression of intrapulmonary tumor.
Figure 2A: Chest x-ray shows bilateral centrallylocated pulmonary mass.
Figure 2B: CT chest shows right upper lobe mass with invasioninto right upper lobe and right main bronchus.
Figure 2C: Shows patency of right main bronchus and area post argonplasma coagulation
Figure 2D: The tumor is composed of plumpspindle cells with lymphoplasma cell infiltrationsimilarly to the first case (Fig 1F). The mitoticactivity is 1/10 HPF.
Both case reports are examples of the variety this tumormay present. In early cases, complete resection is possible andcan result in long term survival with low risk of recurrence.The 5-year and 10-year disease-free survival is 89%12 aftercomplete resection. It can be found centrally located as highas 20%13, therefore if left undiagnosed, it tends to invadebronchus causing curative resection to become very challenging.It can quickly progress to completely block main bronchus tothe point that hemoptysis is one of the presentations.14 Earlyrecannulation of airway is mandatory in this kind of case byeither flexible or rigid bronchoscopy due to rapid progression.Furthermore, it can even metastasize to distant organs15 similarto the second case. The name of this disease itself might soundbenign but it is indeed malignant in its nature. These patientshave a tendency of being diagnosed at a young age, thereforesurgical resection should be encouraged.
In early pulmonary inflammatory myofibroblastic tumor,thoracoscopic complete resection has an excellent short termoutcome and may result in long-term survival. Even inmetastatic cases, palliative airway control also has good shortand mid-term outcomes.