Clinicopathological features of primary leiomyosarcoma of the gastrointestinal tract following recognition of gastrointestinal stromal tumours
ABSTRACT AIMS: We aimed to elucidate the clinicopathological and immunohistochemical features of leiomyosarcoma (LMS) of the gastrointestinal (GI) tract. METHODS AND RESULTS: We encountered seven cases of GI-LMS in the colon (n = 4), rectum (n = 1), jejunum (n = 1) and stomach (n = 1). They ranged from 1 to 25 cm (median, 8.5 cm) in size and had high mitotic counts (median 38 per 50 high-power fields). Morphologically, the tumours were composed mainly of spindle cells with eosinophilic cytoplasm and various degrees of nuclear atypia and pleomorphism. Immunohistochemically, the tumours were positive for α-smooth muscle actin (86%), muscle-specific actin (71%), desmin (86%), calponin (71%), h-caldesmon (57%) and smoothelin (71%). All were negative for KIT, CD34, protein kinase C theta and DOG1. Local recurrence and distant metastasis occurred in one and three patients, respectively. We then reviewed 55 cases of GI-LMS from the era following the recognition of gastrointestinal stromal tumours. Among 29 of 55 cases for whom follow-up information was available, the estimated 5-year overall survival rate was 51.6%; tumour size ≥5 cm was correlated significantly with shorter overall survival time (P = 0.0016), while mitotic count (≥50 or ≥100 per 50 high-power fields) proved to be no prognostic factor. CONCLUSIONS: GI-LMSs have distinctive clinicopathological and immunohistochemical features and exhibit aggressive biological behaviour.
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ABSTRACT: Insulin-like growth factor II messenger RNA-binding protein 3 (IMP3) is a recently identified biomarker demonstrated to be useful in diagnosis and prognostic prediction for several kinds of malignant tumors. However, the clinicopathologic and diagnostic value of IMP3 in mesenchymal tumors of the gastrointestinal tract is not clear. In this study, we examined the immunohistochemical expression of IMP3 in gastrointestinal stromal tumor (GIST) (n = 150), malignant melanoma (n = 17), malignant mesothelioma (n = 6), leiomyosarcoma (n = 6), inflammatory myofibroblastic tumor (IMT) (n = 12), desmoid fibromatosis (n = 8), leiomyoma (n = 20), and schwannoma (n = 20). Focal (≥10%) or diffuse (≥50%) expression with strong staining for IMP3 was judged as positive. We found that malignant melanomas (16/17 cases, 94.1%), malignant mesotheliomas (5/6 cases, 83.3%), IMTs (7/12 cases, 58.3%), and leiomyosarcomas (2/6 cases, 33.3%) were positive for IMP3. Among IMTs and leiomyosarcomas, IMP3-positive cases were histologically and/or clinically aggressive subtypes. Other kinds of tumors, including GIST, desmoid fibromatosis, leiomyoma and schwannoma, were essentially negative for IMP3. Our results suggest that IMP3 may be an ancillary tool in identifying aggressive abdominal mesenchymal tumors other than GIST.Human pathology 10/2013; 45(3). DOI:10.1016/j.humpath.2013.10.010 · 2.81 Impact Factor