Mediastinal rhabdomyoma: a case report and review of the literature

Mesenchymal Tumors of the Mediastinum: An Update on Diagnostic Approach

Mesenchymal tumors of the mediastinum are a heterogenous group of rare tumors with divergent lineages. Mediastinal mesenchymal tumors are diagnostically challenging due to their diversity and morphologic overlap with nonmesenchymal lesions arising in the mediastinum. Accurate histologic diagnosis is critical for appropriate patient management and prognostication. Many mediastinal mesenchymal tumors affect distinct age groups or occur at specific mediastinal compartments. Neurogenic tumors, liposarcoma, solitary fibrous tumor, and synovial sarcoma are common mesenchymal tumors in the mediastinum. Herein, we provide an update on the diagnostic approach to mediastinal mesenchymal tumors and a review of the histologic features and differential diagnosis of common benign and malignant mesenchymal tumors of the mediastinum.

Mesenchymal tumours of the mediastinum--part II

This is the second part of a two-part review on soft tissue tumours which may be encountered in the mediastinum. This review is based on the 2013 WHO classification of soft tissue tumours and the 2015 WHO classification of tumours of the lung, pleura, thymus and heart and provides an updated overview of mesenchymal tumours that have been reported in the mediastinum.

Intraoral adult rhabdomyoma: a case report

A case of adult rhabdomyoma is reported. The lesion is a rare benign tumor of skeletal muscle origin which occurs predominantly in the head and neck region. In the present case, the clinical diagnosis favored a benign salivary gland tumor. Histologically, the tumor was composed of large round, oval, and polygonal cells of varying size with abundant pale, eosinophilic, fine, granular cytoplasm with peripherally located nuclei. Immunohistochemically, the lesion was positive for muscle-specific actin, smooth muscle actin, desmin, S100 protein, and Masson's trichrome. Electron microscopic examination confirmed the presence of numerous myofibrils. The lesion was treated by surgical resection. The clinical, histological, immunohistochemical, and ultrastructural features are discussed in this study.

Adult rhabdomyoma of the extremity

Adult rhabdomyoma is a rare benign tumor. It mainly occurs in the head and neck region and rarely occurs outside the head and neck region. We present an extremely rare case of the adult rhabdomyoma arising in the left foot in a 46-year-old male. Microscopically, large polygonal cells and large strap-shaped cells were observed. This is the third case of adult rhabdomyoma arising in an extremity.

Expression and functional regulation of myoglobin in epithelial cancers

Myoglobin is a multifunctional heme protein that is thought to be expressed exclusively in myocytes. Its importance in both oxygen transport and free radical scavenging has been extensively characterized. We hypothesized that solid tumors could take advantage of proteins such as myoglobin to cope with hypoxic conditions and to control the metabolism of reactive oxygen and nitrogen species. We therefore sought to establish whether myoglobin might be expressed and functionally regulated in epithelial tumors that are known to face hypoxia and oxidative stress during disease progression. We analyzed the expression of myoglobin in human epithelial cancers at both transcriptional and protein levels; moreover, we investigated the expression levels of myoglobin in cancer cell lines subjected to different conditions, including hypoxia, oxidative stress, and mitogenic stimuli. We provide evidence that human epithelial tumors, including breast, lung, ovary, and colon carcinomas, express high levels of myoglobin from the earliest stages of disease development. In human cancer cells, myoglobin is induced by a variety of signals associated with tumor progression, including mitogenic stimuli, oxidative stress, and hypoxia. This study provides evidence that myoglobin, previously thought to be restricted to myocytes, is expressed at high levels by human carcinoma cells. We suggest that myoglobin expression is part of a cellular program aimed at coping with changed metabolic and environmental conditions associated with neoplastic growth.

Mediastinal rhabdomyoma: case report and review of the literature

Rhabdomyomas are benign tumors in which at least some cells are differentiated as skeletal muscle cells with cytoplasmic cross-striations. Extracardiac adult rhabdomyoma is an extremely uncommon benign neoplasm that usually involves the head and neck region. Rare cases have been reported to involve other sites of the body including mediastinum. We report the fourth case of mediastinal adult rhabdomyoma.