Dietmar Schmidt

Bio: Dietmar Schmidt is an academic researcher from Nationwide Children's Hospital. The author has contributed to research in topics: Embryonal rhabdomyosarcoma & Sclerosing rhabdomyosarcoma. The author has an hindex of 1, co-authored 1 publications receiving 152 citations.

Spindle cell variants of embryonal rhabdomyosarcoma in the paratesticular region. A report of the intergroup rhabdomyosarcoma study

Abstract: We reviewed 173 cases of paratesticular rhabdomyosarcoma (RMS) of Intergroup Rhabdomyosarcoma Studies (IRS)-I, -II, and -III for evaluation of possible histological factors that might account for the good prognosis of these patients. Almost all cases (161 of 173 cases, 93.1%) occurring in this site were of embryonal histology. A spindle-cell subtype of embryonal RMS was identified that presented a storiform growth pattern with abundant collagen between the tumor cells in most cases. Other tumors of this subtype showed an arrangement of tumor cells in bundles with a low to moderate amount of collagen, resembling a leiomyosarcoma. The other embryonal RMS in this site had the classical embryonal cytology. The spindle-cell subtype was highly differentiated by immunohistochemistry and electron microscopy. Lymph node metastasis was found in seven of 43 patients (16.3%) with a RMS of spindle-cell subtype, compared with 40 of 112 patients (35.7%) with RMS of non-spindle-cell type. Clinical data from patients with spindle-cell subtypes of the paratesticular lesions revealed that they almost always had an association with clinical groups of limited disease (32 patients, 74.4%, with Group I; 10 patients, 23.3%, with Group II disease) and a significantly better prognosis (95.5% survival at 5 years) when compared with patients with the classic embryonal variant of RMS (80% survival at 5 years, p < 0.035). The incidence and anatomic distribution of this spindle cell subtype of embryonal RMS was estimated on 800 randomly selected patients from IRS-II. It was found in the head and neck, extremities, orbit, and some other sites, but 30.6% were located in the paratesticular area. Patients with spindle cell RMS of nonparatesticular sites usually had more extensive disease compared with patients having paratesticular lesions; two thirds of the cases had gross residual tumor after surgery or metastatic tumor at diagnosis. We conclude that spindle-cell RMS is a subtype of embryonal RMS with a very favorable prognosis. The site factor of the paratesticular localization may allow earlier diagnosis of the spindle-cell lesions compared with other sites. Other unknown factors may also play a role.

Classification of rhabdomyosarcomas and related sarcomas. Pathologic aspects and proposal for a new classification‐an intergroup rhabdomyosarcoma study

Abstract: Background. There is a need to develop a single prognostically significant classification of rhabdomyosarcomas (RMS) and other related tumors of children, adolescents, and young adults which would be a current guide for their diagnosis, allow valid comparison of outcomes between protocols carried out anywhere in the world, and should enhance recognition of prognostic subsets. Method. Sixteen pathologists from eight pathology groups, representing six countries and several cooperative groups, classified by four histopathologic classification schemes 800 representative tumors of the 999 eligible cases treated on Intergroup Rhabdomyosarcoma Study II. Each tumor was classified according to each of the four systems by each of the pathologists. In addition, two independent subsamples of 200 of the 800 patients were reviewed according to the new system, so that 343 distinct patients were reviewed once, and 57 of these twice. Results. A study of the survival rates of all subtypes in the sample of 800 patients led to the formation of a new system. This was tested on two independent subsets of 200 of the original cases and found to be reproducible and predictive of outcome by univariate analysis. A multivariate analysis of the 343 patients classified according to the new system indicated that a survival model including pathologic classification and known prognostic factors of primary site, clinical group, and tumor size was significantly better at predicting survival than a model with only the known prognostic factors. Conclusion. This new classification, termed International Classification of Rhabdomyosarcoma (ICR) by the authors, was reproducible and predictive of outcome among patients with differing histologies treated uniformly on the Intergroup Rhabdomyosarcoma II protocols. We believe it should be utilized by all pathologists and cooperative groups to classify rhabdomyosarcomas in order to provide comparability among and within multi-institutional studies. Cancer 1995;76:1073-85.

Soft Tissue Sarcoma

Abstract: The soft-tissue sarcomas (STS) of childhood are a relatively rare and heterogeneous group of tumors that may occur anywhere in the body and respond quite differently to therapy. STSs account for 7.4% of all cancers in children younger than 20 years [1]. These soft tissue sarcomas are divided almost equally between rhabdomyosarcomas originating from striated muscle and nonrhabdomyosarcoma soft tissue sarcomas (NRSTS). Sarcomas are malignant tumors of mesenchymal cell origin. They are named according to the normal tissue they resemble — for example, rhabdomyosarcoma (skeletal muscle), leiomyosarcoma (smooth muscle), and fibrosarcoma and malignant fibrous histiocytoma (connective tissue), neurofibrosarcoma or malignant peripheral nerve sheath tumor (neurofibrosarcomas, as seen in patients with neurofibromatosis), liposarcoma (adipose), synovial sarcoma (synovium), peripheral nerve sheath tumors (peripheral nerve), and angiosarcoma (blood and/or lymphatic vessels). Other sarcomas include rare entities such as alveolar softpart sarcoma, extraosseous Ewing’s sarcoma, peripheral neuroectodermal tumors, epitheloid sarcoma, and hemangiopericytoma.

Rhabdomyosarcomas in adults and children: an update.

Abstract: Context.—Rhabdomyosarcomas comprise a relatively common diagnostic entity among childhood cancers and a relatively rare one among adult tumors. They may possess a variety of histologies that generally differ among age groups. These lesions appear to be separate biologic entities as well as morphologic categories, with embryonal tumors having genetic lesions related to loss of heterozygosity and aberrant parental imprinting, alveolar tumors containing genetic fusions between PAX and forkhead genes, and pleomorphic tumors showing an accumulation of genetic lesions similar to other adult high-grade sarcomas. Objective.—To present guidelines for diagnosis of rhabdomyosarcoma and recent finding concerning the biology and classification of these lesions. Data Sources.—Review of recent and older published literature and distillation of the authors' experience. Conclusions.—Infants and young children tend to have embryonal rhabdomyosarcomas, adolescents and young adults tend to have alveolar rhabdomyosar...