Inflammatory myofibroblastic tumor: comparison of clinicopathologic, histologic, and immunohistochemical features including ALK expression in atypical and aggressive cases

Steroid responsive inflammatory myofibroblastic tumor of the lung evaluated by FDG PET/CT imaging

A 68-year-old gentleman was referred for ¹⁸F-FDG PET/CT for a pulmonary mass in the left upper lobe which demonstrated intensely FDG-avid confluent pulmonary consolidation in the left upper lobe (SUV_max 15.1). Histopathologic biopsy of the left upper lobe lung mass was consistent with inflammatory myofibroblastic tumor (IMT). The patient was started on steroid treatment in conjunction with antibiotics. Follow-up FDG PET/CT 3 weeks after commence of treatment showed remarkable response of the IMTs to therapy with much less avid FDG uptake (SUV_max 5.4) and marked improvement in the pulmonary consolidation. Nevertheless, the patient underwent left upper lobe lobectomy due to evidence of persistent cystic disease and malignant potential associated with IMTs. Final histopathology was consistent with IMT with no evidence of malignancy.

Inflammatory Myofibroblastic Tumor of the Orbit in a 5-Month-Old Infant

Inflammatory myofibroblastic tumors are mesenchymal neoplasms composed of spindle cells and inflammatory infiltrate. The authors describe a 5-month-old infant with orbital inflammatory myofibroblastic tumor, the youngest patient currently reported in the literature. The histo-pathology, orbital apex location, and patient's age led to a chemotherapy-driven treatment using crizotinib with near-complete resolution of the tumor. [J Pediatr Ophthalmol Strabismus. 2022;59(2):e25-e28.].

Case Report: Early Distant Metastatic Inflammatory Myofibroblastic Tumor Harboring EML4-ALK Fusion Gene: Study of Two Typical Cases and Review of Literature

Inflammatory myofibroblastic tumor (IMT) is a distinctive neoplasm that frequently arises in the lung and accounts for ~1% of lung tumors. Distant metastatic IMT is extremely rare and has been poorly investigated. This analysis was specifically performed to explore the clinicopathological and genetic features of early distant metastatic IMT. Two typical patients with distant metastatic IMTs were selected, which accounted for 1.13% of all diagnosed IMTs in the last 5 years. One patient was a 55 year-old male, and the other patient was a 56 year-old female. Both primary tumors arose from the lung, and the initial clinical symptoms of the two patients involved coughing. Both of the imaging examinations showed low-density nodular shadows in the lungs with enhancement around the mass. Microscopically, dense arranged tumor cells, prominent cellular atypia, and high mitotic activity with atypical form were more prominent in the metastatic lesions than in the primary lesions. All of the primary and metastatic tumors in both cases showed positive anaplastic lymphoma kinase (ALK) immunostaining and ALK rearrangement via fluorescence in situ hybridization. The EML4 (exon 6)-ALK (exon 20) fusion variant (v3a/b) was identified by using next-generation sequencing (NGS) and was verified by using reverse transcription polymerase chain reaction (RT-PCR). Furthermore, intronic variants of NOTCH1 and synonymous variants of ARAF were also detected via NGS in one IMT for the first time and were verified in all of the primary and metastatic lesions via PCR. Distant metastasis occurred during a short period of time (1 and 2 months) after the first surgery. One patient presented with multiple metastases to the subcutaneous tissue and bone that responded to ALK inhibitor alectinib therapy, and the tumor was observed to regress 10 months after the initial ALK inhibitor therapy. In contrast, the other patient presented with subcutaneous neck metastasis without ALK inhibitor treatment and succumbed to the disease within 3 months after the surgery. This study demonstrated the possible role of EML4-ALKv3a/b in the malignant progression of IMT and proposed certain therapeutic effects of ALK inhibitors on multiple metastatic IMTs.

Pediatric Non-Myofibroblastic Primitive Spindle Cell Tumors with ALK Gene Rearrangements and Response to Crizotinib

We describe two poorly differentiated, non-myofibroblastic (SMA-, S100+, CD34±), spindle cell neoplasms with immunohistochemical positivity for ALK and with ALK gene rearrangements leading to PLEKHH2::ALK and CLTC::ALK fusions, respectively. ALK protein overexpression and/or gene fusions should be evaluated in poorly differentiated spindle cell neoplasms, even when there is an absence of a myofibroblastic phenotype. A positive ALK evaluation has therapeutic implications as both tumors responded to single-agent treatment with the tyrosine kinase inhibitor crizotinib.

A huge recurrent retroperitoneal inflammatory myofibroblastic tumor implicating renal and ureter: a case report

Inflammatory myofibroblastic tumor (IMT) is a rare sarcoma with unique molecular characteristics. It also has typical fasciitis-like, dense spindle cells and hypocellular fibrous histologic patterns and can occur at any age. The etiology of IMT is unknown and a complete treatment and monitoring plan for IMT have not been developed. We have found a rare case about a huge recurrent IMT implicating renal and ureter. The patient was accompanied by a history of a lesion sized 15.5 cm × 11.5 cm × 10.5 cm as a retroperitoneal IMT, and the first tumor resection was performed 12 months ago. The patient, who suffered from tumor recurrence within 1 year and whose recurrent tumor also invaded into the renal parenchymal was given a retroperitoneal neoplasm resection plus right nephrectomy. In order to clarify the pathological features, the histological specimens of recurrent retroperitoneal IMT were examined as well as primary retroperitoneal IMT, and immunohistochemical (IHC) stains showed that the spindle cells were positive for vimentin and negative for anaplastic lymphoma kinase (ALK). At 24 months follow-up, the patient recovered well and there was no evidence of tumor recurrence. This case report is conducive to understanding this rare tumor. When conditions permit, complete surgical resection is the recommended treatment for primary and recurrent IMT.

Paediatric Gastrointestinal, Hepatic and Pancreatic Inflammatory Myofibroblastic Tumours, A Single Centre Experience

ABSTRACT

Inflammatory myofibroblastic tumours (IMTs) are rare soft tissue tumours. Reports of gastrointestinal tract, liver and pancreas tumours are limited. The objective of this study is to identify presenting features, contributing prognostic / etiological factors and any variability in outcomes in the context of different historical treatments. We retrospectively reviewed the records of seven children treated at our hospital between 2006 and 2019 and assessed the demographic, presentation, treatment, immunohistochemistry, and outcomes of their tumours. Age range at presentation was 4 months-15 years with a male predominance. Presentations were typically due to local mass effect or incidental discovery. Systemic symptoms were rare. Outcomes were good with six out of seven stable or in remission irrespective of treatment. Surgical resection where possible is the treatment of choice. Medical therapy had good outcomes with chemotherapy acting as first line treatment when required. The only negative prognostic factor identified was local spread at the time of presentation.

Case Report: Recurrence of Testicular Myofibroblastic Tumor After Surgery

Inflammatory myofibroblastic tumour (IMT), also known as plasma cell granuloma (PCG) or inflammatory pseudotumour (IPT), is a distinctive, rarely metastasizing neoplasm composed of myofibroblastic and fibroblastic spindle cells accompanied by inflammatory infiltration of plasma cells, lymphocytes and/or eosinophils. IMT predominantly affects children and young adults, and the age at presentation ranges from 3 to 89 years. We present a very rare case of recurrent testicular IMT without ALK rearrangement. This case highlights the clinical characteristics and diagnostic factors associated with primary and recurrent foci of this rare tumour, along with key therapeutic approaches.

"Inflammatory myofibroblastic tumor of the maxillary sinus: A case report"

Inflammatory myofibroblastic tumors (IMTs) are one of the most complex and rare neoplasms that have been discovered, with varying behavior in different cases. They mostly arise in the thoracic and abdominal cavity, the lungs, retroperitoneum, and extremities. They can also be detected in the head and neck area. IMTs have no age or gender preference which makes them tougher to anticipate. Head and neck IMTs are benign neoplasms with locally aggressive behavior and a low risk of metastatic spread. They have an unknown etiology, and they resemble malignant lesions radiologically. In this case report, we will review the case of a 40-year-old woman with an unusual IMT in the maxillary sinus that presented as a challenge in diagnosis and management.

Assessment of ALK Fusions in Uncommon Inflammatory Myofibroblastic Tumors With ALK IHC Positivity but FISH-Equivocal Findings by Targeted RNA Sequencing

CONTEXT.—

Fluorescence in situ hybridization (FISH) and immunohistochemistry (IHC) are common methods to detect ALK status in inflammatory myofibroblastic tumors (IMTs). However, equivocal ALK FISH signals and inconsistency between FISH and IHC are occasionally observed.

OBJECTIVE.—

To study the inconsistency between FISH and IHC, and clarify ALK status in IMT by targeted RNA sequencing (RNAseq).

DESIGN.—

In this study, 12 consultation cases preliminarily diagnosed as uncommon IMTs with ALK IHC positivity but FISH negativity, plus 3 ALK-positive and 3 ALK-negative IMTs, were re-analyzed by IHC, FISH, and RNAseq.

RESULTS.—

As a result, 1 case with FUS-TFCP2 fusion was detected by RNAseq, which was previously misdiagnosed as IMT. In the other 11 uncommon IMTs, 90.9% (10 of 11) showed equivocal ALK FISH signals, and all were confirmed to harbor ALK fusion by RNAseq, except for 1 failure, suggesting that a low threshold for ALK FISH might be proposed in IMT. Furthermore, RNAseq also identified IGFBP5-ALK in 1 case with ALK IHC positivity but typical FISH negativity, suggesting the possibility of false negatives for ALK FISH. For the typical IMTs, ALK fusion was identified by RNAseq in all 3 ALK-positive IMTs as expected, and additionally FN1-ROS1 fusions were identified in 2 of 3 ALK-negative IMTs.

CONCLUSIONS.—

These findings indicated that RNAseq can simultaneously detect multiple gene fusions and provide fusion forms and breakpoints, which is of great value for differential diagnosis, especially for those uncommon IMTs with equivocal FISH findings, or inconsistency between IHC and FISH.

Mini-invasive endoscopic approach to tracheal inflammatory myofibroblastic tumor in a young woman: A case report

INTRODUCTION

Inflammatory myofibroblastic tumor (IMT) of the trachea is rare tumor mostly found in children and young adults.

CASE REPORT

We report a case of a 28 year-old woman who presented chronic isolated coughing. Chest CT scan showed a tracheal tumor. Rigid bronchoscopy allowed the complete removal of the tumor, and histology confirmed the diagnosis of IMT. 12 months follow-up found no recurrence.

DISCUSSION

IMT is a rare tumor exhibiting both benign and aggressive behaviour. The endoscopic approach of tracheal should be considered when there is a minimal tracheal wall invasion.

CONCLUSION

Through this case, we want to emphasise the role of rigid bronchoscopy in the complete removal of endotracheal IMT.

Inflammatory myofibroblastic tumour of the lung: Case report and review of the literature

Inflammatory myofibroblastic tumour (IMT) of the lung is a rare tumour encountered in children. Although it is seen mostly in paediatric ages, a small number of cases exists in the literature. It may appear as an inflammatory mass or may have the characteristics of a tumour with the ability for recidivism and metastasis. Careful follow-up of the cases is required to differentiate between the two. We present the case of a 4-year-old girl who presented with cough, and the chest x-ray and computed tomography scan revealed a tumour mass in the right lung. After lobectomy, histological examination combined with immunohistochemical study discovered an IMT of the lung.

Spindle Cell Tumors of the Pleura and the Peritoneum: Pathologic Diagnosis and Updates

A diverse group of both benign and malignant spindle cell tumors can involve the pleura or the peritoneum. Due to their rarity and overlapping morphologic features, these tumors can pose considerable diagnostic difficulty in surgical pathology. As these tumors differ in their prognosis and clinical management, their correct pathologic diagnosis is critical. In addition to histologic assessment, select immunohistochemical and molecular tools can aid the distinction among these tumors. In this review, we consider some of the major histologic differential diagnosis of spindle cell tumors involving these serosal membranes. This list of tumors includes: solitary fibrous tumor, inflammatory myofibroblastic tumor, desmoid fibromatosis, synovial sarcoma, sarcomatoid carcinoma, spindle cell melanoma, dedifferentiated liposarcoma, epithelioid hemangioendothelioma, and sarcomatoid mesothelioma. We describe their salient clinicopathologic and genetic findings, with a review on some of the recent discoveries on their molecular pathogenesis.

A Case Report of Inflammatory Myofibroblastic Tumor of the Sphenoidal Sinus

Inflammatory myofibroblastic tumor (IMT) is a tumor composed of differentiated myofibroblastic spindle-shaped cells. It occurs in the soft tissues of the abdomen and lungs, and is very rare in the sphenoid sinus. The diagnosis depends on histopathology and immunohistochemistry, and is easily misdiagnosed. Although metastasis is rare, the recurrence rate is high. Surgical resection is the treatment of choice, and where complete resection is difficult, radiation therapy, hormonal therapy, or molecular targeted drug therapy can be administered. We report a rare case of IMT with a primary origin in the sphenoid sinus, which was entirely resected by nasal endoscopy and confirmed by histological examination.

Anaplastic lymphoma kinase inhibitor therapy in the treatment of inflammatory myofibroblastic tumors in pediatric patients: Case reports and literature review

BACKGROUND

Inflammatory myofibroblastic tumors (IMTs) are a rare subtype of inflammatory pseudotumor frequently associated with rearrangement of the anaplastic lymphoma kinase (ALK) gene. Their treatment has historically relied on at-times challenging and morbid surgical excision. Recent studies have shown that neo/adjuvant therapy with ALK inhibitors can significantly enhance outcomes in select patients.

METHODS

A systematic literature review was performed to characterize comprehensive treatment of ALK-positive IMTs in the pediatric population. This report also includes two patients from our home institutions not previously reported in the literature.

RESULTS

We identified a total of 27 patients in 12 studies in addition to 2 patients from the senior authors' institution for a total of 29 patients (median age, 7 years; 52% male). The IMTs comprised a wide range of anatomic locations. Almost half (12, 41.3%) were treated with ALK-inhibitors alone and felt to be in remission. The remainder was treated with ALK-inhibitors either before or after surgery and had a curative response.

CONCLUSIONS

ALK-positive IMTs can be successfully treated with ALK-inhibition alone or in combination with surgical resection. Further genetic characterization may be helpful in determining more precise treatment and defining needed durations thereof.

Clinicopathologic and Genomic Characterization of Inflammatory Myofibroblastic Tumors of the Head and Neck: Highlighting a Novel Fusion and Potential Diagnostic Pitfall

Inflammatory myofibroblastic tumor (IMT) is a distinctive fibroblastic and myofibroblastic spindle cell neoplasm with an accompanying inflammatory cell infiltrate and frequent receptor tyrosine kinase activation at the molecular level. The tumor may recur and rarely metastasizes. IMT is rare in the head and neck region, and limited information is available about its clinicopathologic and molecular characteristics in these subsites. Therefore, we analyzed a cohort of head and neck IMTs through a multi-institutional approach. Fourteen cases were included in the provisional cohort, but 1 was excluded after molecular analysis prompted reclassification. Patients in the final cohort included 7 males and 6 females, with a mean age of 26.5 years. Tumors were located in the larynx (n=7), oral cavity (n=3), pharynx (n=2), and mastoid (n=1). Histologically, all tumors showed neoplastic spindle cells in storiform to fascicular patterns with associated chronic inflammation, but the morphologic spectrum was wide, as is characteristic of IMT in other sites. An underlying fusion gene event was identified in 92% (n=11/12) of cases and an additional case was ALK-positive by IHC but could not be evaluated molecularly. ALK represented the driver in all but 1 case. Rearrangement of ALK, fused with the TIMP3 gene (n=6) was most commonly detected, followed by 1 case each of the following fusion gene partnerships: TPM3-ALK, KIF5B-ALK, CARS-ALK, THBS1-ALK, and a novel alteration, SLC12A2-ROS1. The excluded case was reclassified as spindle cell rhabdomyosarcoma after detection of a FUS-TFCP2 rearrangement and retrospective immunohistochemical confirmation of rhabdomyoblastic differentiation, illustrating an important diagnostic pitfall. Two IMT patients received targeted therapy with crizotinib, with a demonstrated radiographic response. One tumor recurred but none metastasized. These results add to the growing body of evidence that kinase fusions can be identified in the majority of IMTs and that molecular analysis can lead to increased diagnostic accuracy and broadened therapeutic options for patients.

ALK rearrangements in infantile fibrosarcoma-like spindle cell tumours of soft tissue and kidney

AIMS

Recurrent alterations in receptor tyrosine kinase (RTK) and downstream effectors are described in infantile fibrosarcoma (IFS)/cellular congenital mesoblastic nephroma (cCMN) and a subset of spindle cell sarcomas, provisionally designated 'NTRK-rearranged' spindle cell neoplasms. These two groups of tumours demonstrate overlapping morphologies and harbour alterations in NTRK1/2/3, RET, MET, ABL1, ROS1, RAF1 and BRAF, although their relationship is not fully elucidated. We describe herein a cohort of paediatric tumours with clinicopathological features not typical for inflammatory myofibroblastic tumour, but rather with similarities to cCMN/IFS harbouring ALK fusions.

METHODS AND RESULTS

Clinicopathological features were assessed and partner agnostic targeted RNA sequencing on clinically validated platforms were performed. Tumours occurred in patients aged from 2 to 10 years (median age 2 years) with a 2:2 male to female ratio and an average size of 8.4 cm. Two tumours arose in soft tissues and two in the kidney. Morphological features included spindle to ovoid cells arranged in long fascicles or haphazardly within a myxoid to collagenised stroma; a subset of cases had either dilated, ectatic vessels or focal perivascular hyalinosis. By immunohistochemistry, all cases tested showed cytoplasmic expression of anaplastic lymphoma kinase (ALK) and one case demonstrated co-expression of CD34 and S100.

CONCLUSIONS

This series of ALK-rearranged IFS-like tumours expands the spectrum of targetable kinases altered in these tumours and reinforces the potential overlap between IFS/cCMN-like tumours and the provisional entity of 'NTRK-rearranged' spindle cell neoplasms.

Inflammatory myofibroblastic tumour of an unusual presentation in the uterine cervix: a case report

Background

Inflammatory myofibroblastic tumour is an infrequent mesenchymal neoplasia of unknown aetiology and variable behaviour, ranging from rather benign lesions to locally aggressive and even metastatic disease. Its presence has been described in almost all organs; however, its location in the female genital tract has rarely been reported.

Case presentation

We present the case of a 47-year-old female, who was studied in our institution for a recent medical history of several weeks of dyspareunia and abdominal pain. She underwent pertinent studies including ultrasonography and CT scan. Under suspicion of degenerated leiomyoma, a total hysterectomy was performed. Unexpectedly, the pathological study of the surgical specimen showed very few tumour cells with focal fusiform morphology surrounded by an abundant inflammatory infiltrate; a thorough immunohistochemistry study lead to myofibroblastic tumour of the cervix diagnosis. A PET-CT scan did not show metastatic disease. The patient did not undergo any adjuvant treatment, and she is currently on surveillance with no evidence of disease relapse.

Conclusions

Inflammatory myofibroblastic tumour remains a rare entity yet to be fully elucidated. The diagnosis is based on pathological study due to the lack of typical clinical manifestations and typical radiological images. Surgical resection is the most frequent treatment, whereas chemotherapy and radiotherapy are restricted to locally advanced or metastatic disease. Tirosine kinase inhibitor crizotinib has shown promising results especially in tumours harbouring ALK mutation.

A Recurrent Inflammatory Myofibroblastic Tumor-like Lesion of the Splenic Capsule in a Kitten: Clinical, Microscopic and Ultrastructural Description

OBJECTIVE

To describe the findings of an unusual splenic tumor in a kitten.

METHODS

A grossly multinodular mass arising from the splenic capsule of a 7-month-old male Havana kitten was echographically detected and surgically removed by splenectomy, then analyzed microscopically and ultrastructurally.

RESULTS

The mass showed features of an inflammatory myofibroblastic tumor.

TREATMENT AND OUTCOME

Two months after surgical excision, the mass recurred in the same intra-abdominal area but disappeared after 2 months of anti-inflammatory therapy. Follow-up at 18 months after surgery revealed resolution of the disease.

CLINICAL RELEVANCE

Inflammatory myofibroblastic tumor in cats have been rarely reported and are usually in the orbital region. In the present report, an unusual multinodular gross presentation, a recurrence over time, and a favorable clinical course, are described.

Inflammatory Myofibroblastic Tumor 12 Years After Treatment for Synovial Sarcoma: A Case Report

Inflammatory myofibroblastic tumors (IMTs) are mesenchymal neoplasms most seen in the abdominopelvic region, lung, and retroperitoneum; and less commonly seen in virtually any other site. We report a case of two lower limb masses consistent with diagnosis of IMTs. This is a 39-year-old woman with a history of right lower extremity popliteal fossa synovial sarcoma diagnosed 12 years prior and treated with chemotherapy, surgery, and radiation. She presented with two new - one anterior and one posterior - right thigh masses. Biopsies of the lesions demonstrated low-grade inflammatory spindle cell lesions at both sites. Wide resection was performed for both masses and further characterization of the surgical specimens was most consistent with IMT. At follow-up, the patient is well with no signs of recurrence 19 and 7 months postoperative to the resection of the anterior and posterior thigh masses, respectively. This case represents the first reported IMTs occurring as late as 12 years after primary cancer treatment, and the first occurring after synovial sarcoma.

A rare cause of chronic dysphagia: pulmonary inflammatory myofibroblastic tumor with distal esophagus invasion

Background

Inflammatory myofibroblastic tumor (IMT) is rare intermediate tumor, which happens mostly in children and young adults.

Case presentation

Reported is the successful treatment of a 29-year-old man presented with progressively dysphagia and weight loss. No other abnormal symptoms were observed. The contrast enhanced computed tomography (CT) revealed a dumbbell-shaped lesion between lung and esophagus. Finally, it was pathologically diagnosed as pulmonary IMT invading to the distal esophagus after operation. The patient underwent partial esophagectomy and left lower lobectomy, and was discharged on 10th postoperative day.

Conclusions

IMT is a rare lesion that usually occurs in the lung, but pulmonary IMT with distal esophagus invasion has not been described previously. Discriminating untypical symptom, completed resection, pathological expertise and closed follow-up will reach the successful diagnosis and treatment.

Pediatric and Infantile Fibroblastic/Myofibroblastic Tumors in the Molecular Era

Pediatric fibroblastic/myofibroblastic tumors are rare but include a wide variety of benign to malignant tumors. Given their uncommon frequency, they may present as a diagnostic dilemma. This article is focused on using clinical and pathologic clues in conjunction with the increasingly relevant and available molecular techniques to classify, predict prognosis, and/or guide treatment in these tumors.

Superficial ALK-rearranged myxoid spindle cell neoplasm: a cutaneous soft tissue tumor with distinctive morphology and immunophenotypic profile

Gene rearrangements involving the anaplastic lymphoma kinase (ALK) receptor tyrosine kinase gene have been identified in various neoplasms, including inflammatory myofibroblastic tumor and epithelioid fibrous histiocytoma. We present an ALK-rearranged cutaneous soft tissue tumor with unique morphologic and immunophenotypic features that are not shared by other entities with ALK rearrangements. The six cases involved two females and four males, aged 18-84 (mean 51) years old. Three tumors were on the back and three on the lower extremities (thigh, knee, shin); ranging from 0.5 to 5.6 (mean 2.1) cm. Four were confined to the dermis; two involved the subcutis. All six cases were characterized by the presence of spindled to ovoid cells arranged in concentric whorls and cords against a myxoid to myxohyaline stroma and relatively cellular aggregates of plump ovoid to epithelioid cells. Four cases showed distinct hyalinized blood vessels. Both cases that involved the subcutis showed peripheral lipofibromatosis-like areas. Tumor-infiltrating lymphocytes were absent to moderate. Severe cytologic atypia or conspicuous mitotic activity was not identified. Immunohistochemically, all tumors diffusely expressed ALK (D5F3) and CD34. All but one tumor was diffusely positive for S100 protein. All tumors were negative for EMA, AE1/AE3, SMA, and SOX10. Next-generation sequencing revealed ALK fusions with FLNA (3 cases), MYH10 (2 cases), and HMBOX1 (1 case) as the partner genes. In all six cases, the breakpoints involved exon 20 of ALK, which preserves the receptor tyrosine kinase domains of ALK in the fusion product. Of the four cases with limited follow-up information (2-18 months), none recurred. In conclusion, we report an ALK-rearranged cutaneous soft tissue tumor characterized by the presence of myxoid spindle cell whorls and cords, and co-expression of ALK, CD34, and frequently S100 protein, we term "superficial ALK-rearranged myxoid spindle cell neoplasm".

Inflammatory myofibroblastic tumor of the spleen: a case report

Inflammatory myofibroblastic tumors (IMTs), otherwise known as the inflammatory pseudotumor, is a rare solid mesenchymal tumor, simulating malignant neoplasms, histologically characterized by the proliferation of spindle cells in a fibrous myxoid stroma containing inflammatory cells. CT and MR imaging are the most used tools in their assessment. Clinical features are nonspecific and depend on the localization of the tumor, radiologic findings are polymorphic and no-conclusive and present a diagnostic challenge to the radiologist. Although histology remains obligatory for the final diagnosis. Heren, we report a case of splenic IMT with histological correlation.

Rectal inflammatory myofibroblastic tumor: Case report and literature review

RATIONALE

Rectal inflammatory myofibroblastic tumor (IMT) is an extremely rare mesenchymal tumor characterized by a mixture of spindle-shaped myofibroblasts or fibroblasts and inflammatory infiltration of lymphocytes and plasma cells. To date, only 8 cases of rectal IMT have been reported. Herein, we report an additional case of rectal IMT in a 28-year-old woman.

PATIENT CONCERNS

A 28-year-old woman presented with abdominal pain and hematochezia.

DIAGNOSES

Colonoscopy showed a 3.0-cm subepithelial tumor with central ulceration, covered by white exudate in the rectum. Rectal magnetic resonance imaging revealed a 4.0 × 3.0-cm-sized well-defined subepithelial tumor in the right wall of the rectum, with suspicious right perirectal fat infiltration.

INTERVENTIONS

Laparoscopic anterior resection was performed. Microscopic examination of the surgical specimen revealed bland-looking spindle cells intermingled with lymphoplasma cells. Immunohistochemistry and fluorescence in situ hybridization showed anaplastic lymphoma kinase positivity and anaplastic lymphoma kinase positivity rearrangement. Rectal IMT was confirmed based on histological, immunohistochemical, and fluorescence in situ hybridization findings. The patient was doing well without evidence of tumor recurrence 1 year after the surgery.

LESSONS

Rectal IMT, despite its rarity, should be considered in the differential diagnosis of rectal cancer. Second, an accurate histopathologic diagnosis and complete surgical resection can be the most important approaches to offer a chance for the cure of rectal IMT.

Long-term efficacy update of crizotinib in patients with advanced, inoperable inflammatory myofibroblastic tumour from EORTC trial 90101 CREATE

PURPOSE

European Organisation for Research and Treatment of Cancer (EORTC) 90101 (CREATE) was a prospective, multicentric, non-randomised, open-label phase II basket trial to assess the efficacy and safety of crizotinib in patients with different types of cancers, including advanced inflammatory myofibroblastic tumour (IMT) with or without anaplastic lymphoma kinase (ALK) rearrangements. Here, we report updated results with long-term follow-up.

PATIENTS/METHODS

After central reference pathology, eligible ALK-positive and ALK-negative patients with advanced/metastatic IMT deemed incurable with surgery, radiotherapy or systemic therapy received oral crizotinib 250 mg twice daily. The ALK status was assessed centrally using immunohistochemistry and fluorescence in situ hybridisation. The primary end-point was the proportion of patients who achieved an objective response (i.e. complete or partial response). If ≥6 ALK-positive patients achieved a confirmed response, the trial would be deemed successful.

RESULTS

At data cut-off on 28th January 2021, we performed the final analysis of this trial. Of the 20 eligible and treated patients (19 of whom were evaluable for efficacy), with a median follow-up of 50 months, five were still on crizotinib treatment (4/12 ALK-positive and 1/8 ALK-negative patients). The updated objective response rate (ORR) was 66.7% (95% confidence interval [CI] 34.9-90.1%) in ALK-positive patients and 14.3% (95% CI 0.0-57.9%) in ALK-negative patients. In the ALK-positive and ALK-negative patients, the median progression-free survival was 18.0 months (95% CI 4.0-NE) and 14.3 months (95% CI 1.2-31.1), respectively; 3-year overall survival rates were 83.3% (95% CI 48.2-95.6) and 34.3% (95% CI 4.8-68.5). Safety results were consistent with previously reported data.

CONCLUSION

These updated results confirm previous findings that crizotinib is effective, with durable responses, in patients with locally advanced or metastatic ALK-positive IMT. With further follow-up after the original primary analysis, the ORR increased, as patients derived long-term benefit and some responses converted from stable disease to partial responses.

CLINICAL TRIAL NUMBER

EORTC 90101, NCT01524926.

Inflammatory myofibroblastic tumor of the pancreatic neck: A case report and review of literature

BACKGROUND

Pancreatic inflammatory myofibroblastic tumor (IMT) is a relatively rare disease that is often confused with pancreatic cancer or pancreatic neuroendocrine tumors. The histological features of IMTs show that tissue from this type of tumor contains an intermingling of fibroblast and myofibroblast proliferation, accompanied by a varying degree of inflammatory cell infiltration.

CASE SUMMARY

The management of an IMT occurring at the neck of the pancreas is presented in this paper. A 66-year-old female patient was diagnosed with a pancreatic neck mass after a series of tests. The patient underwent enucleation of the pancreatic neck tumor after a pathological diagnosis of IMT. Previous research on the clinical features, pathological diagnosis and treatment of pancreatic IMTs was reviewed. Compared with previous reports, this is a unique case of enucleation of a pancreatic IMT.

CONCLUSION

The enucleation of pancreatic IMTs may be a safe and efficient surgical method for managing such tumors with a better prognosis. Further cases are required to explore surgical measures for pancreatic IMTs.

Rapid Response to Lorlatinib in a Patient With TFG-ROS1 Fusion Positive Inflammatory Myofibroblastic Tumor of the Chest Wall Metastatic to the Brain and Refractory to First and Second Generation ROS1 Inhibitors

Most inflammatory myofibroblastic tumors (IMTs) harbor ALK fusions but oncogene fusions involving ROS1, RET, NTRK, and PDGFR also occur. The recognition that most IMTs harbor receptor tyrosine kinase fusions has provided a rationale for the use of tyrosine kinase inhibitors to target these oncogenic drivers in advanced IMTs. Crizotinib has been effective in ALK and ROS1-positive IMTs but resistance eventually develops. Here we report the successful use of lorlatinib in a patient with heavily pretreated ROS1-positive IMT of the chest wall with acquired crizotinib-resistance and metastasis to the brain.

Inflammatory myofibroblastic tumor: molecular landscape, targeted therapeutics, and remaining challenges

Inflammatory myofibroblastic tumor (IMT) is a rare mesenchymal tumor of intermediate malignant potential that predominantly affects children, adolescents and young adults. IMT has a predilection for the lung, abdomen, pelvis, and retroperitoneum, however, can affect any part of the body. IMT is typically localized, and multifocal or metastatic disease is uncommon. Complete surgical resection is the treatment of choice when feasible. There is no established standard of care for unresectable and advanced IMT. Approximately half of IMTs harbor anaplastic lymphoma kinase (ALK) gene rearrangements, and fusions involving ROS1, PDGFRβ, RET and NTRK have also been described. Given the molecular landscape of IMT, management of these tumors has evolved to include tyrosine kinase inhibitors and novel targeted therapeutics. This review highlights the molecular characteristics, evolution of targeted therapies and the remaining challenges in the management of IMT.

Therapeutic options in inoperable ROS1-rearranged inflammatory myofibroblastic tumor of the tongue in a child: a case report and literature review

Inflammatory myofibroblastic tumor (IMT) is a rare borderline malignancy, usually treated with surgery only. Exceedingly rare cases of inoperable, recurrent, or metastatic IMTs pose a therapeutic challenge. We report successful treatment of a 7-year-old girl with an inoperable anaplastic lymphoma kinase (ALK)-negative IMT of the tongue. The patient underwent various anti-inflammatory (steroids, nonsteroidal anti-inflammatory drugs, clarithromycin) and antiproliferative (chemotherapy) therapies to enable tumor regression and complete resection. Ultimately, next-generation sequencing of the tumor revealed a TFG-ROS-1 translocation, allowing for an off-label targeted therapy with crizotinib. Crizotinib treatment caused slight tumor regression but evident change of its structure, allowing for complete non-mutilating resection. Two histopathology examinations revealed complete disappearance of neoplastic cells following therapy. The patient remains disease-free 22 months after the delayed surgery. In children with inoperable ALK-negative IMTs, molecular testing must be performed to identify other targetable oncogenic fusions, including TFG-ROS1.

A forensic autopsy case: Sudden unexpected death due to cardiac inflammatory myofibroblastic tumor

We report an autopsy case of a 25-year-old man with no medical history who died suddenly in an Internet cafe. He was found in cardiorespiratory arrest and did not respond to cardiopulmonary resuscitation. Traumatic lesions were not observed on his body. An autopsy was performed to investigate the cause of death. Upon examination, we discovered a heart tumor that infiltrated from the outside wall to the outflow tract of the left ventricle. Left ventricular outflow tract obstruction due to a cardiac tumor was considered the mechanism of death. Histological examination identified an inflammatory myofibroblastic tumor (IMT). The final diagnosis was death secondary to circulatory failure due to a cardiac IMT. Additionally, a cardiac tumor was diagnosed using post-mortem computed tomography. Only few cases of sudden unexpected death due to cardiac IMT have been reported; we report this case along with a review of the literature.

Mesenchymal tumours of the gastrointestinal tract

Mesenchymal tumours represent a heterogenous group of neoplasms encopassing benign, intermediate malignancy, and malignant entities. Sarcomas account for approximately 1% of human malignancies. In consideration of their rarity as well as of intrinsic complexity, diagnostic accuracy represents a major challenge. Traditionally, mesenchymal tumours are regarded as lesions the occurrence of which is mostly limited to somatic soft tissues. However, the occurrence of soft tissue tumours at visceral sites represent a well recognized event, and the GI-tract ranks among the most frequently involved visceral location. There exist entities such as gastrointestinal stromal tumours (GIST) and malignant gastointestinal neuroectodermal tumors that exhibit exquisite tropism for the GI-tract. This review will focus also on other relevant clinico-pathologic entities in which occurrence at visceral location is not at all negligible.

Inflammatory myofibroblastic tumors arising from pancreas head and peri-splenic area mimicking a malignancy

Inflammatory myofibroblastic tumors (IMTs) are a rare chronic inflammatory disease with unclear pathogenesis and pathological features that are not those of a malignant tumor. It is difficult to differentially diagnose them without surgical excision because of their unpredictable clinical behavior, which ranges from benign to locally invasive aggressiveness. We report two cases of IMTs that were diagnosed after surgery. In one case, the IMT originated in peri-splenic area in a 63-year-old female patient. The other case involved a 48-year-old female patient who suffered from an IMT of the head of the pancreas. Both of these cases did not require further treatment based on histological findings, and there has been no evidence of recurrence or metastasis so far. These cases show that the primary choice for the exact diagnosis and proper treatment of IMTs is complete surgical resection.

Durable response to serial tyrosine kinase inhibitors (TKIs) in an adolescent with metastatic TFG-ROS1 fusion positive Inflammatory Myofibroblastic Tumor (IMT)

Here, we present the case of an adolescent with a rare metastatic Inflammatory myofibroblastic tumor (IMT) harboring a TFG-ROS1 fusion initially detected on tumor progression and retrospectively identified in the primary tumor after targeted RNA sequencing. The patient benefitted from sequential TKIs over a 5-year period with response to the third generation ALK/ROS inhibitor, lorlatinib leading to resection of the primary tumor. Detailed molecular analysis can identify targetable oncogenic kinase fusions that alters management in patients with unresectable disease and should be considered in all patients.

ALK-negative lung inflammatory myofibroblastic tumor in a young adult: A case report and literature review of molecular alterations

RATIONALE

Inflammatory myofibroblastic tumor (IMT) is a rare mesenchymal tumor that is prevalent among children and adolescents. Surgery is the most important therapeutic approach for IMT and complete resection is recommended. Although 50% of IMTs show anaplastic lymphoma kinase (ALK) rearrangements, crizotinib has proven an effective therapeutic approach. However, the genetic landscape of this tumor is still not fully understood and treatment options are limited, especially in the majority of ALK-negative tumors.

PATIENT CONCERNS

We describe the clinical case of a healthy 18-year-old female in whom a pulmonary nodule was incidentally detected.

DIAGNOSES

Following a small increase in the size of the nodule, the patient underwent both 18FDG-PET/CT and 68Ga-PET/CT, resulting in a suspicion of bronchial hamartoma.

INTERVENTIONS

The patient underwent surgery and a salivary gland-like lung tumor was diagnosed.

OUTCOMES

After surgery, the patient was referred to our cancer center, where a review of the histology slides gave a final diagnosis of ALK-negative lung IMT. Given the histology, it was decided not to administer adjuvant therapy and the patient was placed in a 3-monthly follow-up program. The patient is still disease-free 2 years post-surgery.

LESSONS

Although there is no standard of care for the treatment of IMT, identifying genomic alterations could help to redefine the management of patients with negative-ALK disease. Our review of the literature on IMT and other kinase fusions revealed, in addition to ALK rearrangements, the potential association of ROS1, NTRK, RET, or PDGFR beta alterations with the tumor.

Inflammatory myofibroblastic tumor in the pancreatic neck: a rare case report and literature review

Inflammatory myofibroblastic tumor (IMT) is a rare disease of unknown etiology. It usually occurs in abdominal soft tissues and lung, and is extremely rare in the pancreas. IMT can occur in any part of a person at any age, however, it mostly affects children and young people. Its clinical manifestations are atypical, imaging examinations are not specific, and the differential diagnosis of pancreatic malignancies is difficult, making it easily misdiagnosed. Surgical resection is the preferred method of treatment for IMT. In this case report, we report a rare case of IMT in the neck of the pancreas and reviewed the relevant literature. In our case, the patient was a 57-year-old woman with an IMT in the neck of the pancreas. Abdominal pain was the only clinical symptom, and imaging features were not specific. She underwent surgery to remove the pancreatic mass, and the final diagnosis of IMT was based on histopathology and immunohistochemistry. After 6 months of regular follow-up, the patient had no complications or further incidents. The purpose is to emphasize the difficulty of the preoperative diagnosis of pancreatic IMT and the difficulty of distinguishing it from pancreatic malignancies. It is hoped that clinicians can gain a deeper understanding of pancreatic IMT through this case report.

A Rare Inflammatory Myofibroblastic Tumor of the Mitral Valve With Systemic Embolism in a Child

Inflammatory myofibroblastic tumors (IMTs) represent mesenchymal tumors that occur in the lungs, abdomen, or pelvis. Cardiac IMTs are rare, usually right-sided, and when left-sided can cause sudden cardiac death by coronary occlusion. We report a child with symptoms of embolization to the right kidney and the femoral artery, and a mobile mass in the left atrium attached to the mitral valve. Upon surgical removal, histopathology revealed IMT. Our case illustrates a unique presentation of systemic thromboembolism.

Rare presentation of inflammatory myofibroblastic tumor on a digit

Inflammatory myofibroblastic tumors (IMTs) are rare soft tissue neoplasms consisting of a mixture of spindle-shaped myofibroblasts or fibroblasts and a variable inflammatory infiltrate composed of eosinophils, plasma cells, and lymphocytes. Associations with trauma and infectious agents have been proposed, but the etiology is unknown. While IMT predominantly develops in the lungs of pediatric patients or young adults, extrapulmonary IMT is well documented and may occur anywhere. Cutaneous IMT is rare and few have been reported on the hand in the English language. The mean age of onset is 10 years, with a slight female predilection. IMT demonstrates intermediate malignant potential, with a tendency to recur locally. Metastases are rare. According to a recent review, anaplastic lymphoma kinase (ALK) positivity on immunohistochemistry is related to local recurrence, but not distant metastases. We report an unusual case of a 36-year-old male, with a lesion on the right second digit, displaying classic histopathologic and immunohistochemical features of IMT, including ALK staining, and confirmatory fluorescence in situ hybridization-proven ALK gene rearrangement.

A rare case of inflammatory myofibroblastic tumor of the vulva in a newborn

Inflammatory myofibroblastic tumor (IMT) is an uncommon neoplasm that rarely arises in the genitourinary system. IMTs in the vulva in infants are extremely rare in the literature. The tumor consists of myofibroblastic spindle cells accompanied by inflammatory cell infiltration. In this article, we aimed to describe the case of IMT in the vulva. A newborn girl presented with a mass in the vulva detected in the prenatal period. The patient was treated with surgery and chemotherapy. Follow-up 8 months after surgery showed no signs of recurrence. In conclusion, IMT has a variable clinical presentation, surgery is the optimal approach, but in cases without complete resection, chemotherapy is essential.

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 tumours in central airways: bronchoscopic treatment of a “not so pseudo-” tumourhttps://bit.ly/2KgPntq

Translating Molecular Profiling of Soft Tissue Sarcomas into Daily Clinical Practice

Soft tissue sarcomas are a group of rare mesenchymal tumors with more than 70 subtypes described. Treatment of these subtypes in an advanced setting is mainly according to a one-size-fits-all strategy indicating a high unmet need of new and more targeted therapeutic options in order to optimize survival. The introduction of advanced molecular techniques in cancer has led to better diagnostics and identification of new therapeutic targets, leading to more personalized treatment and improved prognosis for several cancer types. In sarcoma, a likewise evolution is seen, albeit at a slower pace. This manuscript describes how in the past years advanced molecular profiling in soft tissue sarcomas was able to identify specific and often pathognomonic aberrations, deferring standard sarcoma treatment in favor of more targeted treatment from an oncologist’s point of view.

[Extramammary myofibroblastoma affecting the pelvic region: a case report]

Un myofibroblastome de type mammaire est une tumeur molle rare; les myofibroblastomes extramammaires sont particulièrement rare. Un homme de 78 ans s'est présenté en consultation pour des douleurs pelviennes soulagées par la défécation ou les urines. Le toucher rectal retrouve une masse en avant de la paroi rectale antérieure. L'imagerie par résonance magnétique (IRM) montre une masse de 10 x 6 x 8cm, bien circonscrite et hétérogène, située en arrière de la vessie qu'elle refoule vers l'avant, en avant du recto-sigmoïde. L'immunohistochimie montre des cellules tumorales co-exprimant CD34 et la desmine de façon diffuse, expression de Rb dans la majorité des cellules, expression des récepteurs aux œstrogènes, expression intense et diffuse de la P16, un index de prolifération avec le ki67 estimé à 25%. Il n'y a pas eu de récidive après 8 mois de radiothérapie d'induction suivie de chirurgie. Un myofibroblastome de type mammaire est une tumeur rare et bénigne. La récidive n'est quasiment pas observée après traitement local. Ce cas permet de mettre en avance la possibilité d'utiliser la radiothérapie afin de faciliter la chirurgie.

Pseudosarcomatous myofibroblastic proliferations of the urinary bladder are neoplasms characterized by recurrent FN1-ALK fusions

Pseudosarcomatous myofibroblastic proliferation is a descriptive term that designates a group of clinically indolent genitourinary lesions that most commonly arise in the urinary bladder. Given that pseudosarcomatous myofibroblastic proliferation may show morphologic overlap with inflammatory myofibroblastic tumor, the relationship, if any, between the two entities has been unclear. Moreover, pseudosarcomatous myofibroblastic proliferations are known to be positive for ALK immunohistochemistry in a subset of cases, although an inconsistent association with ALK rearrangement (ranging from 0 to 60%) has been reported. The objectives of this study were to determine the frequency of ALK rearrangement and to identify fusion partners using fluorescence in situ hybridization (FISH) and targeted RNA sequencing studies in a contemporary series of 30 pseudosarcomatous myofibroblastic proliferations of the urinary bladder, as well as to investigate ROS1 status by immunohistochemistry. ALK immunohistochemistry was positive in 70% (21/30) of pseudosarcomatous myofibroblastic proliferations; ROS1 immunohistochemistry was consistently negative (0/28). ALK rearrangements were detected by FISH in 86% (18/21) of cases, correlating with ALK immunohistochemical positivity in all but 3 cases. Of eight cases confirmed to be ALK rearranged by FISH, targeted RNA-sequencing detected FN1-ALK fusions in seven (88%) cases, which involved exons 20-26 of FN1 (5') and exon 18-19 of ALK (3'). In conclusion, ALK rearrangements are frequent in pseudosarcomatous myofibroblastic proliferations, typically involving exon 19, and FN1 appears to be a consistent fusion partner. Given the significant clinicopathologic differences between inflammatory myofibroblastic tumor and pseudosarcomatous myofibroblastic proliferation, our findings provide further support for classification of pseudosarcomatous myofibroblastic proliferation as a distinct clinicopathologic entity, and propose the alternate terminology "pseudosarcomatous myofibroblastic neoplasm of the genitourinary tract."

Primary inflammatory myofibroblastic tumor of stomach-report of a very rare case

Primary inflammatory myofibroblastic tumor (IMT) is a very rare tumor arising from stomach and it closely mimics gastric GIST. It usually affects the lung and found in children and young patients. The diagnosis of gastric IMT is usually done post-operatively by immunohistochemistry examination where it is seen that IMT is positive to SMA and vimentin. Complete surgical excision is the treatment of choice and local recurrence is usually seen in incompletely resected cases.