“…Whether OMH represents a single entity or a distinct subtype of IMT with specific morphologic, molecular, and clinical features is still a matter of debate [3,5]. In the present study, four cases of OMH in infancy are described, and in comparison with IMT, their occurrence in newborns is exceptional, only a few cases having been reported in the literature [15][16][17][18]. Our cases were characterized macroscopically by single or multiple peritoneal localizations, without involvement of the intra-abdominal parenchymal organs.…”
Omental mesenteric myxoid hamartoma (OMH) is a distinctive myxoid lesion of infancy, characterized by a benign clinical behavior. In the current World Health Organization (WHO) classification of soft tissue tumors, it is considered as part of the morphologic spectrum of inflammatory myofibroblastic tumors (IMT), but this relationship with IMT is still subject to debate. Four lesions with histologic features of OMH occurring in newborns and toddlers are described and compared with classic, ALK-positive IMT. All OMH showed a peculiar dot-like immunostaining for ALK, which, in one of the cases, was cytogenetically found to be associated with an inversion of the ALK gene. While OMHs were positive for smooth muscle actin (SMA), desmin, WT1, podoplanin, and cytokeratins (CAM5.2 and AE1-3), IMT were consistently positive only for SMA (10 cases). ALK-1 displayed cytoplasmic staining in IMT and characteristic paranuclear dot-like staining in OMH.
“…Whether OMH represents a single entity or a distinct subtype of IMT with specific morphologic, molecular, and clinical features is still a matter of debate [3,5]. In the present study, four cases of OMH in infancy are described, and in comparison with IMT, their occurrence in newborns is exceptional, only a few cases having been reported in the literature [15][16][17][18]. Our cases were characterized macroscopically by single or multiple peritoneal localizations, without involvement of the intra-abdominal parenchymal organs.…”
Omental mesenteric myxoid hamartoma (OMH) is a distinctive myxoid lesion of infancy, characterized by a benign clinical behavior. In the current World Health Organization (WHO) classification of soft tissue tumors, it is considered as part of the morphologic spectrum of inflammatory myofibroblastic tumors (IMT), but this relationship with IMT is still subject to debate. Four lesions with histologic features of OMH occurring in newborns and toddlers are described and compared with classic, ALK-positive IMT. All OMH showed a peculiar dot-like immunostaining for ALK, which, in one of the cases, was cytogenetically found to be associated with an inversion of the ALK gene. While OMHs were positive for smooth muscle actin (SMA), desmin, WT1, podoplanin, and cytokeratins (CAM5.2 and AE1-3), IMT were consistently positive only for SMA (10 cases). ALK-1 displayed cytoplasmic staining in IMT and characteristic paranuclear dot-like staining in OMH.
“…4 [28]. To the best of our knowledge, one case of urinary bladder IMT with the ATIC-ALK fusion mutation and one case of IMT arising from the hyoid bone in a neonate with the ATIC-ALK fusion have been reported in the literature [23, 29]. Thus, the present case is the first IMT with the ATIC-ALK fusion mutation primarily in the mandible.Fig.…”
BackgroundInflammatory myofibroblastic tumor (IMT) is a rare low-grade malignant neoplasm with a predilection for children and young adults, and typically arises in the lung, abdominopelvic region, and retroperitoneum. IMTs in the maxillofacial region are extreme rare. Approximately 50% of IMT harbor rearrangements of the anaplastic lymphoma kinase (ALK) gene at 2p23 with various fusion partners.Case presentationWe herein report a case of intraosseous IMT of the mandible with a novel ATIC-ALK fusion. Tooth 43 did not erupt after the loss of tooth 83 in an 11-year-old girl with no previous history of trauma. Panoramic tomography showed a unilocular radiolucent lesion in the right anterior mandible resorbing the root of tooth 42 and the medial side of the root of tooth 44. Computed tomography revealed a well- circumscribed 3-cm osteolytic lesion of the right anterior mandible eroding the buccal cortical plate. The entire lesion was curetted out. A histopathological examination revealed the proliferation of plump spindle cells with a storiform architecture and lymphocytes scattered around spindle cells. The spindle cells showed diffuse cytoplasmic staining for ALK by immunohistochemistry. A fluorescence in situ hybridization analysis revealed the translocation of a part of the ALK gene locus at chromosome 2p23. A rapid amplification of cDNA ends analysis confirmed the rearrangement of ALK and identified ATIC as a partner of this ALK fusion mutant.ConclusionTo the best of our knowledge, this is the first case of intraosseous IMT of the mandible with a novel ATIC-ALK fusion. We also herein reviewed similar tumors reported in the literature.
“…Histological examination of typical pediatric pulmonary IMTs reveals fascicles of myofibroblastic cells admixed with an inflammatory infiltrate consisting of lymphocytes, plasma cells, and eosinophils [7]. Histological analysis of these tumors in older children reveals fascicles of spindle cells, which are consistent with IMT, but with little inflammatory infiltration [18,19]. Coffin et al reported the immunohistochemical analysis of IMT in which immunoreactivity for muscle-specific actin (89%) and smooth muscle actin (92%) varied from a focal to a diffuse pattern in the cytoplasm of spindle cells; generally, smooth muscle actin staining was more prominent than musclespecific actin reactivity [6].…”
Section: Pathological Findingsmentioning
confidence: 98%
“…Liu et al [5] reported that, in general, IMT patients who are candidates for surgical resection have a favorable prognosis, with 5-and 10-year survival rates of 91% and 77%, respectively [20]. Nevertheless, approximately 8% of pulmonary IMTs without indications for surgery have a continuous growth pattern, with 5% of patients at risk of developing distant metastasis [18]. Distant metastases appear mainly in ALK-negative IMTs, but local recurrence occurs regardless of ALK expression [6].…”
Background: Spontaneous pneumothorax occurs more often in younger, slim, and shallow-chested men. Although less common, differential diagnoses for secondary pneumothorax in children are asthma, emphysematous blebs, catamenial pneumothorax, and others. We report a patient who presented with pneumothorax and was found to have an inflammatory myofibroblastic tumor (IMT)-like lesion, and present a review of the related literature. Case presentation: A 14-year-old girl visited her physician for chest pain that developed while exercising. Although chest drainage was performed, the symptoms associated with a collapsed lung did not improve, and she was referred to our hospital. Computed tomography revealed the presence of a 19 × 17-mm cyst with a thick wall in the apex of the right lung. She was tested for infectious diseases, namely tuberculosis, but the results were not definitive. Catamenial pneumothorax was also suspected because she was menstruating when she presented to our hospital. As a therapeutic diagnosis, we performed a thoracoscopic partial resection of the right upper lobe of the lung. Three small openings were identified inside the cyst, suggesting connection with the bronchiole. The lesion was pathologically diagnosed as an IMT-like lesion. Considering the progress so far, we considered that the final diagnosis to be an IMT. The patient was discharged on postoperative day 3, and we have followed her for the past 6 months with no local recurrence or metastasis. Conclusions: IMT is not uncommon in children. Therefore, this lesion should be considered as a possible diagnosis if children and young adults develop spontaneous pneumothorax.
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