Test Catalog

Test ID: IMTF    
Inflammatory Myofibroblastic Tumors (IMT), 2p23 (ALK) Rearrangement, FISH, Tissue

Useful For Suggests clinical disorders or settings where the test may be helpful

Supporting the diagnosis of inflammatory myofibroblastic tumor when used in conjunction with an anatomic pathology consultation

Testing Algorithm Delineates situations when tests are added to the initial order. This includes reflex and additional tests.

This test does not include a pathology consult. If a pathology consultation is requested, PATHC / Pathology Consultation should be ordered and the appropriate FISH test will be ordered and performed at an additional charge.


This test includes a charge for application of the first probe set (2 FISH probes) and professional interpretation of results.


Additional charges will be incurred for all reflex probes performed. Analysis charges will be incurred based on the number of cells analyzed per probe set. If no cells are available for analysis, no analysis charges will be incurred.

Clinical Information Discusses physiology, pathophysiology, and general clinical aspects, as they relate to a laboratory test

Inflammatory myofibroblastic tumor (IMT) is a distinctive lesion composed of myofibroblastic spindle cells accompanied by an inflammatory infiltrate of plasma cells, lymphocytes, and eosinophils which occur primarily in the soft tissue and viscera of children and young adults. They may arise in any anatomical site including lung, soft tissue, retroperitoneum, and bladder.


The genetic mechanisms underlying IMT pathogenesis are only partially known, but cytogenetic analyses have disclosed chromosomal rearrangements involving the ALK gene at 2p23. Studies support that identification of ALK gene rearrangement is useful to differentiate IMTs from other spindle cell neoplasms of soft tissue and viscera.

Reference Values Describes reference intervals and additional information for interpretation of test results. May include intervals based on age and sex when appropriate. Intervals are Mayo-derived, unless otherwise designated. If an interpretive report is provided, the reference value field will state this.

An interpretive report will be provided.

Interpretation Provides information to assist in interpretation of the test results

A neoplastic clone is detected when the percent of cells with an abnormality exceeds the normal cutoff for the ALK probe set.


A positive result is consistent with a subset of inflammatory myofibroblastic tumor (IMT).


A negative result suggests that an ALK gene rearrangement is not present but does not exclude the diagnosis of IMT.

Cautions Discusses conditions that may cause diagnostic confusion, including improper specimen collection and handling, inappropriate test selection, and interfering substances

This test is not approved by the U.S. Food and Drug Administration and it is best used as an adjunct to existing clinical and pathologic information.


Fixatives other than formalin (eg, Prefer, Bouin's) may not be successful for FISH assays, however nonformalin-fixed samples will not be rejected.


Paraffin-embedded tissues that have been decalcified are generally unsuccessful for FISH analysis. The pathologist reviewing the hematoxylin and eosin-stained slide may find it necessary to cancel testing.

Supportive Data

FISH analysis was performed on 76 formalin-fixed, paraffin-embedded tissue samples. These included 26 inflammatory myofibroblastic tumors (IMT) (21 bladder and 5 soft tissue), 33 non-IMT spindle tumors, and 50 noncancerous control specimens (25 bladder and 25 soft tissue). The normal controls were used to generate a normal cutoff for this assay. Rearrangement of ALK was identified in 18 of 26 IMT specimens. Immunohistochemical staining confirmed these were negative for ALK-1. The remaining spindle cell tumors were also negative for ALK rearrangement and ALK-1 staining.

Clinical Reference Recommendations for in-depth reading of a clinical nature

1. Coffin CM, Fletcher JA: Chapter II: Inflammatory myofibroblastic tumour. In World Health Organization Classification of Tumors. Pathology and Genetics of Tumours of Soft Tissue and Bone. Edited by CDM Fletcher, KK Unni, F Mertens. Lyon, IARC Press, 2002, pp 91-93

2. Sukov WR, Cheville JC, Carlson AW: Utility of ALK-1 protein expression and ALK rearrangements in distinguishing inflammatory myofibroblastic tumor from malignant spindle cell lesions of the urinary bladder. Mod Pathol 2007 May;20(5):592-603

3. Tsuzuki T, Magi-Galluzzi C, Epstein JI: ALK-1 expression in inflammatory myofibroblastic tumor of the urinary bladder. Am J Surg Pathol 2004;28:1609-1614

4. Li XQ, Hisaoka M, Shi DR: Expression of anaplastic lymphoma kinase in soft tissue tumors: an immunohistochemical and molecular study of 249 cases. Hum Pathol 2004 Jun;35(6):711-721

5. Griffin CA, Hawkins AL, Dvorak C, et al: Recurrent involvement of 2p23 in inflammatory myofibroblastic tumours. Cancer Res 1999;59:2776-2780