Pulmonary inflammatory myofibroblastic tumor versus IgG4-related inflammatory pseudotumor: differential diagnosis based on a case series

Nonspecific inflammatory pseudotumor of the maxillary and temporal fossa: a study of seven cases

OBJECTIVE

Inflammatory pseudotumor (IPT) is a rare, locally aggressive, benign neoplasm of unknown etiology. Because of its aggressive clinical behavior and locally destructive or infiltrative features, it may be mistaken for a malignant tumor. Approximately 5%-44% of extrapulmonary IPT occur in the head and neck, primarily affecting the orbit.

STUDY DESIGN

Between 2008 and 2021, our hospital received referrals for seven patients (three men and four women, aged 42-73 years) with pain, swelling, mass, and trismus. Computed tomography, magnetic resonance imaging, and biopsy were performed on all patients to diagnose IPT.

RESULTS

Of the seven patients, four received low-dose prednisolone (PSL), one underwent surgery, and two were left untreated. The IPT disappeared in one of the two untreated cases, whereas it improved and later deteriorated in the other. The surgical patient had no recurrence. Low-dose PSL was effective in two patients; however, high-dose PSL and immunosuppressants were required in the remaining two cases owing to infiltration into each orbit or brain region.

CONCLUSIONS

Low-dose PSL treatment was applicable in IPT cases affecting the maxillary to temporal fossa region, wherein symptoms did not improve without treatment. However, when low-dose PSL was ineffective, high-dose PSL and immunosuppressants were required.

Inflammatory myofibroblastic tumor of the heart in an older woman with paroxysmal atrial fibrillation: a case report and review of the literature

Inflammatory myofibroblastic tumors (IMTs) of the heart are rarely observed in the eldly. We report a case involving an elderly woman with an IMT situated on the right atrial wall. The tumor was fully excised. The patient had a smooth recovery post-surgery and remained free of recurrence for three years.

Inflammatory myofibroblastic tumor of the pancreatic neck misdiagnosed as neuroendocrine tumor: A case report

BACKGROUND

Inflammatory myofibroblastic tumor (IMT) is a relatively rare tumor. The global incidence of IMT is less than 1%. There is no specific clinical manifestation. It usually occurs in the lungs, but the pancreas is not the predilection site.

CASE SUMMARY

We present a case of a male patient, 51 years old, who was diagnosed with a pancreatic neck small mass on ultrasound one year ago during a physical examination. As he had no clinical symptoms and the mass was relatively small, he did not undergo treatment. However, the mass was found to be larger on review, and he was referred to our hospital. Since the primal clinical diagnosis was pancreatic neuroendocrine tumor, the patient underwent surgical treatment. However, the case was confirmed as pancreatic IMT by postoperative pathology.

CONCLUSION

Pancreatic IMT is relatively rare and easily misdiagnosed. We can better under-stand and correctly diagnose this disease by this case report.

Inflammatory myofibroblastic tumor of the lung involving the central nervous system in pediatric patients

INTRODUCTION

The inflammatory myofibroblastic tumor (IMT) is a very rare lesion with an incidence of less than 0.1% of total neoplasms and with main affection in the lungs. Involvement in the central nervous system is extremely rare, but with a much more aggressive course than IMT diagnosed in the rest of the body. We report the 2 cases presented in our neurosurgery department to date; both were treated satisfactorily without intercurrences in 10 years of follow-up.

HISTORICAL BACKGROUND

The World Health Organization described the IMT as a distinctive lesion composed of myofibroblastic spindle cells accompanied by an inflammatory infiltrate of plasma cells, lymphocytes, and eosinophils.

CLINICAL PRESENTATION

Clinical manifestations of patients with CNS IMT vary and may consist of headache, vomiting, seizures, and blindness. Seizures are the most common symptom in patients with focal lesions.

DIAGNOSIS

The true origin of this entity remains to be elucidated, but to date, etiologies ranging from chromosomal alterations to autoimmune or postinfectious mechanisms have been described. Due to its rarity and non-specificity in imaging, the final diagnosis of IMT in the brain parenchyma relies on pathological examination.

MANAGEMENT

Treatment options are controversial and include total or subtotal removal, high-dose steroids, and radiation therapy. In the last decade, the development of ALK Tyrosine Kinase Inhibitors allows the possibility of chemotherapy in those patients harboring ALK mutations.

CONCLUSION

IMT is a rare tumor that can exceptionally be found in the CNS. The cause is still unknown although the different studies focus on a neoplastic origin. The diagnosis is based in the use of different modalities of imaging and with histological confirmation. Optimal management is gross total resection whenever possible, is the only established curative treatment. Further research with longer follow-up is needed to clarify the natural history of this rare tumor.

A Common Cell of Origin for Inflammatory Myofibroblastic Tumor and Lung Adenocarcinoma with ALK rearrangement

This case signifies the importance of obtaining tumor comprehensive genomic profiling (CGP) as it has utility in cancer type classification and helping in diagnosing recurrence/metastasis or separately occurring primary tumors. CGP can also help guiding treatment as in this case separately occurring Inflammatory Myofibroblastic Tumor had ALK fusion and responded to crizotinib. As treatment progresses, new biopsies should be obtained and CGP used to evaluate for appearance of any new genomic alterations, in order to guide further therapy.

What do we know about inflammatory myofibroblastic tumors? - A systematic review

BACKGROUND

Inflammatory myofibroblastic tumors (IMTs) are rare intermediate-grade neoplasms that have a high recurrence rate after excision and exhibit low metastatic potential. These tumors contain proliferating neoplastic, fibroblastic and myofibroblastic cells, and are also characterized by chronic inflammatory infiltration by lymphocytes, plasma cells, eosinophils, and histiocytes. They belong to the group of inflammatory spindle cell lesions. Some reactive lesions, such as inflammatory pseudotumors, may appear to be IMTs, which makes their differential diagnosis extremely difficult. The aim of this article is to compile the recent information on IMTs to aid in their diagnosis and treatment.

METHODS

We reviewed articles published between 2017 and 2021, which were selected from online medical databases. In addition, some earlier articles and latest scientific monographies were analyzed.

RESULTS

The terminology used for inflammatory spindle cell lesions seems to be confusing. The terms "inflammatory myofibroblastic tumors" and "inflammatory pseudotumors" are interchangeably used by many scientists. However, a detailed analysis of the development of terminology suggests that the term "inflammatory myofibroblastic tumors" should be used to refer to a neoplastic lesion.

CONCLUSIONS

IMTs are rare neoplasms, which have not been investigated in detail due to the difficulty in collecting a large number of cases. Thus, our knowledge about this disease remains unsatisfactory. Recently developed techniques such as next-generation sequencing and computer-aided histopathological diagnosis may be useful in understanding the etiopathology of IMTs, which will help in the selection of the most appropriate therapy for patients.

CT Signs and Differential Diagnosis of Peripheral Lung Cancer and Inflammatory Pseudotumor: A Meta-Analysis

We aimed to systematically evaluate the imaging features of peripheral lung cancer and inflammatory pseudotumor. PubMed, Embase, Cochrane Library, Chinese Knowledge Infrastructure (CNKI), Wanfang database (Wanfang), and Chinese Biomedical Network (CBM) were searched to collect relevant studies on CT image comparison of peripheral lung cancer and inflammatory pseudotumor. The search time was from database establishment to July 15, 2021. The search language was limited to Chinese and English. Data from the literature were screened and extracted, and meta-analysis was performed using Stata 16.0 software. A total of 8 cohort studies were included in this meta-analysis, including 675 patients. Meta-analysis showed that the lesion size of inflammatory pseudotumor was greater than that of peripheral lung cancer, and the difference had statistical significance [SMD = 0.29, 95% CI (0.01, 0.58), P < 0.05]. The difference in HU value between inflammatory pseudotumor and peripheral lung cancer CT had no statistical significance [SMD = -0.09, 95% CI (-0.79, 0.60), P > 0.05]. The HU value of enhanced CT of inflammatory pseudotumor was higher than that of peripheral lung cancer, and the difference had statistical significance [SMD = 0.75, 95% CI (0.15, 1.34), P < 0.05]. The incidence of calcification of inflammatory pseudotumor was significantly higher than that of peripheral lung cancer, and the difference had statistical significance [RR = 2.85, 95% CI (1.33, 6.11), P < 0.05]. The incidence of long hair puncture sign of inflammatory pseudotumor was lower than that of peripheral lung cancer, and the difference had statistical significance [RR = 0.49, 95% CI (0.24, 0.97), P < 0.05]. There was no significant difference between inflammatory pseudotumor and peripheral lung cancer in terms of cavity incidence, vacuole sign, pleural indentation, and bronchial inflation sign (P > 0.05). Based on the available literature evidence, it can be found that there are differences in the CT signs between peripheral lung cancer and inflammatory pseudotumor, and the lesion size, HU value on enhanced CT, incidence of calcification, and incidence of burr sign may be important indicators for differentiating peripheral lung cancer from inflammatory pseudotumor.

Distinct clinicopathological features of pulmonary primary angiomatoid fibrous histiocytoma: A report of four new cases and review of the literature

BACKGROUND

The aim of this study was to highlight the clinicopathological features of pulmonary primary angiomatoid fibrous histiocytoma (PPAFH) to assist with a differential diagnosis.

METHODS

There were 10 previous reports in the literature and four new PPAFH cases reviewed in this study. Immunohistochemistry (IHC), fluorescence in situ hybridization (FISH) and DNA and RNA-based next-generation sequencing (NGS) was performed in the four new cases reported here.

RESULTS

In the four new PPAFH cases, the ages of occurrence were in patients age from 33 to 55 years and tumor sizes were from 1.5 to 8 cm. Three of four (75.0%) tumors were located in the endobronchus. The most common morphological changes included delineated fibrous capsule (100%, 4/4), lymphoplasmacytic cuff (100%, 4/4), and dense or richly lymphoplasmatic infiltration (100%, 4/4). IHC analysis revealed that the tumor cells of four cases expressed vimentin and TLE1, ALK and CD163 or CD68 was positive in three cases, epithelial membrane antigen (EMA), desmin was positive in two cases, and SMA focal positive expression was observed in two cases. EWSR1 gene rearrangement was positive in all PPAFH cases (100%, 4/4) by FISH detections and four cases were confirmed as EWSR1-CREB1 fusion variant by DNA and RNA based NGS. No regional lymph nodes and distal metastasis, recurrences and death of disease after surgical excision were recorded in all four cases.

CONCLUSIONS

PPAFH is a very unusual pulmonary primary mesenchymal tumor and the clinicopathological features are like other unusual sites counterparts, but with a smaller tumor size, related with large airway, with a tendency to exhibit benign biological behavior, with EWSR1 gene rearrangement and higher frequency of EWSR1-CREB1 gene fusion.

KEY POINTS

Significant findings in the study: In comparison with "classic somatic" and nonpulmonary visceral angiomatoid fibrous histiocytoma, pulmonary primary angiomatoid fibrous histiocytoma display distinct clinicopathological features and prognosis. What this study adds The study provided the pathological differential diagnostic criteria and clinico-pathological features for pulmonary primary angiomatoid fibrous histiocytoma.

Clinical characteristics and outcomes of 17 cases of inflammatory myofibroblastic tumor at a University Hospital in China

The aim of the present study was to explore the clinical and pathological characteristics, diagnosis, and treatment of inflammatory myofibroblastic tumor (IMT). A total of 17 patients with IMT diagnosed between July 2010 and February 2020 were included in the present study, and the clinical characteristics, pathological features, treatment and prognosis were analyzed retrospectively. The cohort consisted of 17 participants, including 12 men and 5 women, with a mean age of 34.76 years. The most common locations of tumors were the bronchi and the lungs (9 cases, including 1 case involving the mediastinum), followed by the colon and bladder (2 cases each), and the omentum majus, mesocolon, stomach and peritoneal cavity (1 case each). Immunohistochemical staining demonstrated that the tumor cells exhibited positive staining for anaplastic lymphoma kinase p80 (13/17), smooth muscle actin (12/17), cytokeratin pan (6/17), vimentin (5/17) and desmin (4/17). The follow-up time was 18-114 months. A patient with epithelial inflammatory myofibroblast sarcoma (EIMS) succumbed to the disease, 1 case was lost to follow-up, 2 cases relapsed and the other 13 cases were considered cured. IMTs may be malignant or low-grade. EIMS is a rare and invasive variant of IMT. The clinical and imaging manifestations are often unique and vary among individuals. Once confirmed by pathology, radical surgery should be the first choice of treatment.

Inflammatory myofibroblastic tumour of the central airways: treatment and molecular analysis

Inflammatory myofibroblastic tumours (IMT) are a rare cause of endobronchial masses in adults. Surgery has been the mainstay of treatment of endobronchial IMTs, based on the potential for recurrence. Interventional pulmonology has emerged as a minimally invasive and lung function preserving modality in management of airway obstruction due to tumours. We present a series of three adult patients with IMT treated endobronchially with a short discussion on its potential role. We also discuss how molecular analysis of IMTs for mutations in genes such as ALK and ROS1 might provide insights into clinical behaviour and potential targetable therapy in advanced, unresectable and metastatic cases.

Inflammatory myofibroblastic tumor of the lung: A rare endobronchial mass

A 42-year old male was referred with a 6-week history of new onset dyspnea. The patient had normal vital signs, no relevant medical history and the only abnormality was a left sided inspiratory wheeze. No abnormalities were seen on the chest X-ray. A bronchoscopy was performed which showed a well-circumscribed hypervasculated mass in the left main bronchus. A biopsy was taken, which was complicated after the procedure by dislocation of the mass and coughed up by the patient. Both samples were send for pathologic review. A contrast CT was performed which showed a localized remaining mass in the left main bronchus and no lymph node involvement. Pathological evaluation showed spindle-shaped cell proliferation with mitotic activity in the second larger tissue which could be consistent with an inflammatory myofibroblastic tumor (IMT), whereas the first biopsy sample only showed granulomatous inflammation. Following multidisciplinary review the diagnosis of IMT was made and a treatment plan was decided. Because of the localized position of the mass the patient was treated with laser coagulation via rigid bronchoscopy instead of surgery. Bronchoscopic review afterwards showed complete resolution of the mass and the dyspnea had resolved. This case highlights the difficulty of making the IMT-diagnosis and the option of treating it with laser coagulation via rigid bronchoscopy.

Inflammatory myofibroblastic tumours of the thorax: Radiologic and clinicopathological correlation

CONTEXT AND AIMS

Inflammatory myofibroblastic tumour (IMT) is a rare mesenchymal neoplasm with intermediate malignant potential. The aim of this study is to describe and compare the clinical presentation, computed tomography (CT) findings and anaplastic lymphoma kinase -1 (ALK-1) expression of IMT of the thorax in children and adults. We also sought to study the tumour behaviour after treatment on the follow-up imaging.

MATERIALS AND METHOD

This is a retrospective observational study of 22 histopathologically proven cases of IMT in the thorax. The clinical parameters, CT findings, biopsy results, treatment received and follow-up were recorded. Statistical analysis was performed using Fisher's exact test.

RESULTS

IMT of the thorax had diverse imaging appearances, presenting either as large invasive lung masses with or without calcifications or as smaller endobronchial lesions. Children commonly presented with long duration fever (P = 0.02) and large invasive lung masses (P = 0.026), whereas adults presented with long duration haemoptysis (P = 0.001) and endobronchial lesions or smaller lung parenchymal lesions. Calcifications were more common in children (P = 0.007). ALK-1 was positive in 40% of children and 18.2% of adults (P = 0.547). Endobronchial lesions showed a trend for ALK-1 negativity. Patients with bronchoscopic excision had local recurrence and patients with surgical wedge resection had metastatic brain lesions as compared to those with lobectomy and pneumonectomy (P = 0.0152). A patient with unresectable lung mass had malignant transformation to spindle cell sarcoma after 9.5 years.

CONCLUSIONS

Thoracic IMT presents with some distinct clinical and CT findings in adults and children. The CT findings and management options have implications for prognosis. If resectable, lobectomy is a better option than wedge resection or bronchoscopic excision for preventing local recurrence and metastasis. IMT can undergo malignant transformation.

Aggressive Inflammatory Myofibroblastic Tumor without Anaplastic Lymphoma Kinase Gene Rearrangement in the Rectum with Liver Metastasis

Inflammatory myofibroblastic tumor is a rare intermediate-grade tumor. We herein report the case of an 81-year-old man with rectal ulceration and abnormal retroperitoneal soft tissue with a high serum level of IgG4. The administration of prednisolone reduced the retroperitoneal lesion; however, the rectal ulceration expanded. Surgical resection was performed. A histopathological examination revealed proliferating spindle cells accompanied by inflammatory cells and plasma cells. Liver metastasis emerged two months after surgical resection, and the histology of the proliferating spindle cells sampled by a fine-needle biopsy was similar to that of the rectal tissue. The patient ultimately died of inflammatory myofibroblastic tumor.

Inflammatory Myofibroblastic Tumor of the Pancreas: A Case Report and Literature Review

Inflammatory myofibroblastic tumors (IMTs) are rare. They are characterized by myofibroblastic spindle cell proliferation with a varying degree of inflammatory cell infiltration. IMT can occur in any anatomic location but has been reported in the lung, mesentery, and omentum, mainly in children or young adults. It rarely occurs in the pancreas and is often difficult to distinguish from other tumors, including some malignant ones. Therefore, it can be challenging to make a radiological diagnosis of IMT. Here, we present a case of IMT that occurred in the pancreas head of a middle-aged female. The patient’s ultrasonography, computed tomography, and magnetic resonance imaging findings are presented along with a review of the literature.

Imaging of Unusual Renal Tumors

PURPOSE OF REVIEW

Renal masses are a wide entity and a common finding in clinical practice. Detection of these masses has increased in the last years, yet mortality rates have slightly decreased.

RECENT FINDINGS

According to the World Health Organization classification, there are 8 types, 51 subtypes, and a lot more subsequent subclassifications of renal tumors. Histopathological analysis should always be assessed for final diagnosis of theses tumors. However, imaging can be an important diagnostic guidance. The most common diagnoses of renal tumor are clear cell carcinoma, papillary renal cell carcinoma, angiomyolipoma, and transitional cell carcinoma. Nonetheless, a considerable variety of particular tumors can arise from the kidney, challenging the expertise of radiologists and urologists on this subject. The awareness of these unusual entities is vital for professionals working at a complex medical facility with greater volume of patients. We hereby present uncommon renal tumors and its pathological and radiological features.

Recurrent inflammatory myofibroblastic tumour of the lung: FDG PET/CT scan findings

Inflammatory myofibroblastic tumour (IMT) is a rare neoplasm, occurring most often in children and young adults. IMTs have intermediate biological behaviour with the chance of local invasion, recurrence and even distant metastasis. Wide range of clinical presentations makes the precise diagnosis of IMT more challenging. The best method for definitive diagnosis is tissue biopsy and newer imaging modalities including fleurodeoxyglucose (FDG) positron emission tomography (PET)/CT are useful tools in detection of disease recurrence or distant metastasis. Complete surgical resection is the best-known treatment for this tumour. Here we are presenting an IMT case in a 12-year-old girl in which her recurrent pulmonary IMT was diagnosed based on FDG PET/CT findings and referred for further salvage treatment. Overall imaging modalities are not specific, but PET/CT scan can be useful tool for evaluation of IMT regarding initial staging and restaging to assess treatment response and recurrence.

The Clinical and Radiological Characteristics of Inflammatory Myofibroblastic Tumor Occurring at Unusual Sites

Inflammatory myofibroblastic tumor (IMT) can occur rarely in the soft tissue or joint of the limb. We retrospectively collected IMT cases of these rare sites and analyzed their clinical and imaging appearance. Thirteen cases of IMT were clinically diagnosed and underwent surgical procedures, pathological analyses, and postsurgical follow-up in our two hospitals. Other than one case of IMT of the bladder wall that presented with gross hematuria, none presented with local swelling, fever, or weakness. All the cases of IMT occurring at the bone showed destruction and parosteal soft tissue masses. The boundaries between the mass and normal bone were vague, without calcifications or any periosteal reaction. Five cases of IMF showed continuous enhancement on CT; seven cases demonstrated iso- or hyposignal intensity on T1WI; one case showed hypersignal intensity on T1WI, and eight cases demonstrated a hypersignal intensity signal on T2WI. All the masses located in soft tissues showed clear and sharp boundaries with different sizes of the swelling regions surrounding muscle interspaces. Three cases showed homogeneous enhancement, one case demonstrated heterogeneous enhancement, and two cases showed edge enhancement on enhanced MRI scans. On pathology, all the lesions showed an absence of a pseudocapsule, and four cases of ALK were positive. The radiological manifestations of IMT located at the soft tissue and bones were similar to benign tumors in shape; however, peritumoral edema, parosteal soft tissue, and the invasive rim of IMT are similar to the features of malignant tumors. Different radiological methods should be used to obtain an accurate diagnosis.