Inflammatory Myofibroblastic Tumor of the Upper Airways Harboring a New TRAF3-ALK Fusion Transcript

Abdominal inflammatory myofibroblastic tumour: Clinicopathological and molecular analysis of 20 cases, highlighting potential therapeutic targets

AIMS

Inflammatory myofibroblastic tumour (IMT) is a rare mesenchymal neoplasm of intermediate malignant potential, occurring at any age and at multiple sites. Epithelioid inflammatory myofibroblastic sarcoma (EIMS) is an aggressive subtype of IMT, typically involving the abdomen. Most IMTs harbour kinase gene fusions, especially involving ALK and ROS1, but 20-30% of IMTs show no detectable translocations. The aim of this study is to further delineate clinicopathological and molecular characteristics of abdominal IMT and discover potential new therapeutic targets.

METHODS AND RESULTS

In 20 IMTs, including four EIMS, RNA fusion analysis was performed, followed by multiplex DNA analysis if no ALK or ROS1 fusion was detected. Fourteen IMTs (70.0%) had an ALK translocation and the fusion partner was identified in 11, including a RRBP1::ALK fusion, not previously described in classical (non-EIMS) IMT. RANBP2::ALK fusion was demonstrated in all EIMS. One IMT had a ROS1 fusion. In all ALK/ROS1 translocation-negative IMTs mutations or fusions - as yet unreported in primary IMT - were found in genes related to the receptor tyrosine kinase (RTK)/PI3K/AKT pathway. Three of four patients with EIMS died of disease [mean survival 8 months (4-15 months)], whereas only one of 14 classical IMT patients succumbed to disease [mean follow-up time 52 months (2-204 months); P < 0.01].

CONCLUSION

This study shows the wide clinical spectrum of abdominal IMTs and affirms the poor prognosis of EIMS, raising discussion about its status as IMT subtype. Furthermore, the newly detected alterations of the RTK/PI3K/AKT pathway expand the molecular landscape of IMTs and provide potential therapeutic targets.

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.

Crizotinib in Sarcomatous Malignancies Harboring ALK Fusion With a Definitive Partner(s): Response and Efficacy

Sarcoma or sarcomatoid malignancies are a set of mesenchymal-origin malignancies with vast heterogeneity in clinical and molecular characteristics. Anaplastic lymphoma kinase (ALK) is a tyrosine kinase oncoprotein expressed by several tumors, including sarcomas. Crizotinib is an effective ALK inhibitor. In this review paper, we summarized findings from the literature regarding the use of crizotinib for the treatment of sarcoma and sarcomatoid malignancies harboring ALK fusions with definitive partners (with the given gene(s) name) from the years 2010 to 2021.One hundred and four articles were retrieved and after exclusion, 28 studies containing 33 patients were finally selected. All 33 patients were treated with crizotinib. Among the 33 cases, 19 were adult patients, 11 were pediatric patients, and 3 cases did not have data on age and/or gender. Most cases had a primary abdominal lesion (16/30), followed by thoracic (10/30), trunk (3/30), retroperitoneal (1/30), and one case of right medial thigh (case 7). Stage IV disease was reported in 76.7% (23/30) of patients. The objective response rate and disease control rate was 86.7% (26/30) and 96.7% (29/30), respectively, which were assessed on average of 8 weeks after crizotinib initiation. Rapid improvement of symptoms was observed within one to two weeks in some cases including patients with extensive diseases or poor performance. There was no difference in crizotinib response between pediatrics and adult cases. Crizotinib is effective; however, surgery remains the mainstay of therapy, with newer evidence showing concurrent crizotinib with surgery conferring long-term overall survival. However, we should still be cognizant of the heterogeneous landscape of crizotinib efficacy and its associated fatal adverse events.