Metastatic inflammatory myofibroblastic tumor identified by EUS‐FNA in mediastinal lymph nodes with ancillary FISH studies for ALK rearrangement

Abstract

Inflammatory myofibroblastic tumor (IMT) is an exquisitely rare neoplasm with a low incidence of metastasis. Previously, cytologic diagnosis of this entity, by fine needle aspiration (FNA) or endoscopic ultrasound guided fine needle aspiration (EUS-FNA), was challenging, if not impossible. However, advancements in the field of molecular pathology, the applications of which have lagged in cytopathology relative to other disciplines, now makes diagnosis possible. Here we report a case of pulmonary inflammatory myofibroblastic tumor with mediastinal nodal metastasis in a 74-year-old man, definitively diagnosed by EUS-FNA utilizing morphologic, immunohistochemical, and molecular findings, including fluorescent in situ hybridization studies for ALK gene rearrangement. This case report demonstrates the value of ancillary molecular studies to assist in the diagnosis of rare neoplasms, including those at sites of metastasis.

Cytodiagnosis of inflammatory myofibroblastic tumor: A report of three cases in infants

“…Core needle biopsy for intra‐abdominal tumors is not recommended, because of difficult accessibility of the tumor sites. Only few reports, on molecular studies of IMT, on endoscopic ultrasound‐guided FNAC material have been described and can be particularly useful for diagnosis at metastatic sites …”

“…There are only a few case reports available describing the cytological findings of IMT. [6][7][8] The largest series out of these is by Stoll and Li where in a series of 20 patients, a confident diagnosis of inflammatory myofibroblastic tumor could be made on cytology, in 15% cases only. 6 In their series, there were only three intra-abdominal cases and the youngest patient reported was a 7 years old child.…”

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

“…In this study, seeking to avoid the missed diagnosis for IMTs, IgG4-positive cells >60/HPF and IgG4+/IgG+plasma cells >50% were taken as a diagnostic criterion for IgG4-related IPTs. Besides, based on previous literatures and the discovery of the (8,10,(16)(17)(18). The rearrangements cause ALK protein overexpression and can be detected by immunohistochemistry and fluorescence in situ hybridization (FISH) (8).…”

Cytopathologic features of epithelioid inflammatory myofibroblastic sarcoma with correlation of histopathology, immunohistochemistry, and molecular cytogenetic analysis

“…To the best of our knowledge, the cytopathology literature regarding IMT or inflammatory pseudotumor is limited to case reports and small series . Because of its rarity and novelty, E‐IMS has not yet come within the scope of cytopathology.…”

“…10,11,13 To the best of our knowledge, the cytopathology literature regarding IMT or inflammatory pseudotumor is limited to case reports and small series. [14][15][16][17][18][19] Because of its rarity and novelty, E-IMS has not yet come within the scope of cytopathology. Nevertheless, the recognition of E-IMS in cytologic specimens should be underscored in view of its nearly exclusive intraabdominal presentation mimicking carcinomatosis of the peritoneum clinically, and hence the likelihood of using paracentesis and/or fine-needle aspiration (FNA) as the first-line approaches to obtain tissue diagnosis.…”