ALK-Positive Inflammatory Myofibroblastic Tumor of the Abdomen With Widespread Microscopic Multifocality

Abstract

Inflammatory myofibroblastic tumor (IMT) is a locally aggressive neoplasm, most frequently occurring in the abdominal cavity as multiple recurrent nodules. We report a case of IMT in a 24-year-old male presenting as multiple nodules involving the omentum, the liver, and the colon. Spindle tumor cells expressed ALK with a cytoplasmic granular distribution, the CLTC-ALK fusion gene was demonstrated by reverse-transcriptase polymerase chain reaction analysis, and break-apart fluorescence in situ hybridization (FISH) probes for the ALK gene showed a pathological pattern (single red signal associated with 1/2 normal fused signals) highly suggestive for combined gene fusion and deletion. To reduce the surgically unresectable liver mass, the patient was treated with crizotinib, and after 4 months of treatment the disease was defined stable according to RECIST criteria. Interestingly, ALK and FISH/FICTION analysis revealed that tumor cells were widely dispersed as multiple microscopic foci or as single cells beneath the omental mesothelium. These findings indicate that IMT multifocality might result either from dissemination from the main tumor mass or development of multiple independent neoplastic foci; furthermore, they underline the need of omentectomy in abdominal IMT to obtain surgical radicality.

STUMP un“stumped”: anti-tumor response to anaplastic lymphoma kinase (ALK) inhibitor based targeted therapy in uterine inflammatory myofibroblastic tumor with myxoid features harboring DCTN1-ALK fusion

“…Response to crizotinib in IMT harboring ALK fusions have also been observed in two patients [21, 25, 26]. In this case report, we describe the documented clinical response of a uterine IMT to a combination of crizotinib and pazopanib.…”

Crizotinib in ALK+ inflammatory myofibroblastic tumors—Current experience and future perspectives

“…However, these studies did not report individual patient data. The median age of the 16 patients included in case reports was 22 years (range 4–71 years), and five patients were younger than 18 years . The median age of the children included in the COG study was 7 years (range 2–13.5 years) …”

“…The median age of the 16 patients included in case reports was 22 years (range 4-71 years), and five patients were younger than 18 years. 14,[25][26][27][28][29][30][31][32][33][34][35][36][37] The median age of the children included in the COG study was 7 years (range 2-13.5 years). 24 Nine of the 16 patients included in case reports had tumors with IMT histology of spindle cell stroma with leukocyte/plasma cell infiltrate, whereas histology of the other seven patients showed a myxoid stroma with round epithelioid cells and a neutrophil infiltrate representing the IMT variant EIMS.…”

Multiple malignant inflammatory myofibroblastic tumors of the jejunum: A case report and literature review

“…Due to the rarity of IMTs, only a few cases have been reported in the literature to date (2)(3)(4)(5)(6)(7)(8)(9)(10)(11)(12)(13)(14)(15)(16)(17), and the incidence rates remain unclear. IMTs are most prevalent in the pulmonary system of children and young adults, however, they may also develop in older patients and in other organs (18).…”

“…In the aggressive forms of IMT, exhibiting a high local recurrence rate and a potential for metastasis, it is recommended that close follow-up consisting of physical examination, radiographic imaging and the evaluation of serial erythrocyte sedimentation rates is undertaken (15). It has also been recommended that post-surgical adjuvant treatments are administered for intraabdominal IMT, as it has the highest rate of local recurrence (25%) (17). The present patient underwent a clear margin surgical excision with no further adjuvant therapy.…”