h-Caldesmon (h-CD) is a protein combined with actin and tropomyosin that regulates cellular contraction. h-CD has been thought to be expressed exclusively in vascular and visceral smooth muscle cells (SMC). We examined h-CD expression immunohistochemically in tumors with SMC and SMC-like differentiation to clarify whether h-CD is specifically expressed in SMC tumors. The tumors examined in this study were six leiomyomas (LM), two angioleiomyomas (ALM), six leiomyosarcomas (LMS), eight rhabdomyosarcomas (RMS), eight malignant fibrous histiocytomas (MFH), four desmoids, three glomus tumors (GT), and two inflammatory myofibroblastic pseudotumors (IMP) of urinary bladder. We found that LM, ALM, LMS, and GT showed intense and extensive immunoreactivity for h-CD, whereas other tumors were completely negative for h-CD. In addition, h-CD was not present in the vascular pericytes and myofibroblasts, in contrast to actin. Although myoepithelial cells were immunopositive for h-CD, neoplastic myoepithelial cells of myoepithelial tumors and mixed tumors of the salivary gland and skin were all negative. These findings indicate that h-CD is a specific marker of both SMC and its neoplasms and that immunohistochemical detection of h-CD may facilitate the differential diagnosis between LMS and other tumors with SMC-like differentiation, including myofibroblastic tumors.
"While in some cases this was due to lack of use of antibodies such as h-caldesmon and beta-catenin, in many the appropriate antibodies were used, but interpretation of morphologic features and immunohistochemical staining patterns led to discordant referring and tertiary centre diagnoses. Common sources of error included (a) diagnosing leiomyosarcoma based on focal expression of smooth muscle actin (SMA) and desmin alone, without the use of more specific smooth muscle markers  (as SMA can be diffusely expressed in myofibroblasts in both reactive and neoplastic conditions, and desmin is a broad spectrum marker of muscle lineage and is also expressed in other lesions such as myofibroblastoma), (b) interpreting cytoplasmic and especially paranuclear beta-catenin staining as positive for fibromatosis , and (c) interpreting overstaining or background staining of some antibodies, such as cytokeratins or CD31. "
[Show abstract][Hide abstract] ABSTRACT: Introduction. Soft tissue tumour pathology is a highly specialised area of surgical pathology, but soft tissue neoplasms can occur at virtually all sites and are therefore encountered by a wide population of surgical pathologists. Potential sarcomas require referral to specialist centres for review by pathologists who see a large number of soft tissue lesions and where appropriate ancillary investigations can be performed. We have previously assessed the types of diagnostic discrepancies between referring and final diagnosis for soft tissue lesions referred to our tertiary centre. We now reaudit this 6 years later, assessing changes in discrepancy patterns, particularly in relation to the now widespread use of ancillary molecular diagnostic techniques which were not prevalent in our original study. Materials and Methods. We compared the sarcoma unit's histopathology reports with referring reports on 348 specimens from 286 patients with suspected or proven soft tissue tumours in a one-year period. Results. Diagnostic agreement was seen in 250 cases (71.8%), with 57 (16.4%) major and 41 (11.8%) minor discrepancies. There were 23 cases of benign/malignant discrepancies (23.5% of all discrepancies). 50 ancillary molecular tests were performed, 33 for aiding diagnosis and 17 mutational analyses for gastrointestinal stromal tumour to guide therapy. Findings from ancillary techniques contributed to 3 major and 4 minor discrepancies. While the results were broadly similar to those of the previous study, there was an increase in frequency of major discrepancies. Conclusion. Six years following our previous study and notably now in an era of widespread ancillary molecular diagnosis, the overall discrepancy rate between referral and tertiary centre diagnosis remains similar, but there is an increase in frequency of major discrepancies likely to alter patient management. A possible reason for the increase in major discrepancies is the increasing lack of exposure to soft tissue cases in nonspecialist centres in a time of subspecialisation. The findings support the national guidelines in which all suspected soft tissue tumour pathology specimens should be referred to a specialist sarcoma unit.
"However, Watanabe et al., has suggested H-caldesmon to be specific for smooth muscle cell and tumors originating from it. He showed consistent expression of H-caldesmon in normal visceral and vascular smooth muscle cells and also myoepithelial cells but not in myofibroblasts and vascular pericytes. "
[Show abstract][Hide abstract] ABSTRACT: Gingival angioleiomyoma are rarely encountered lesions and most of these lesions are excised in toto in view of reactive gingival epulitic lesions. However, due to the vascular nature of these lesions, many a times surgeons experience unexpected hemorrhage and require extensive hemostatic management. A preoperative diagnosis is a must for these lesions and at least color imaging techniques can be utilized to know its vascular nature and preoperative tumor embolization can be done to be on the safer side. Also histopathological dilemma can occur due to the varied types of vascular arrangement in angioleiomyoma or due to simulation of other vascular lesion like hemangiomas, as well as due to similarity with other spindle cell neoplasms. We advocate the use of immunohistochemistry (IHC) to establish the exact diagnosis in such cases. Also due to infrequent reports of angioleiomyoma in such unusual location, we want to record this case for further reference in future.
Journal of Oral and Maxillofacial Pathology 04/2014; 18(1):107-10. DOI:10.4103/0973-029X.131928
"Differential diagnosis of IMT includes benign diseases such as leiomyoma, postoperative spindle cell nodule, nodular fasciitis, and neurofibroma and malignant diseases such as leiomyosarcoma, embryonal rhabdomyosarcoma, and sarcomatoid carcinoma. Immunohistochemistry remains the cornerstone for diagnosis of IMT with positive stain for vimentin (95% to 100%), desmin (5% to 80%), smooth muscle actin (48% to 100%), muscle-specific actin (62%), and keratin (10% to 89%) and negative stains for epithelial membrane antigen, myogenin, p53, and h-caldesmon [4,6-8]. ALK stains positive in approximately half of these tumors and is a promising marker for differentiation of IMTs from other lesions . "
[Show abstract][Hide abstract] ABSTRACT: Inflammatory myofibroblastic tumor of the urinary bladder is a rare mesenchymal tumor with uncertain malignant potential. It often mimics soft tissue sarcomas both clinically and radiologically. Surgical resection in the form of partial cystectomy or transurethral resection remains the mainstay of treatment. Herein we report the case of an inflammatory myofibroblastic tumor in a young girl, which was managed by laparoscopic partial cystectomy. To the best of our knowledge, this is the first reported case of laparoscopic management of an inflammatory myofibroblastic tumor of the urinary bladder.
Korean journal of urology 11/2013; 54(11):797-800. DOI:10.4111/kju.2013.54.11.797
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