[Myxoid tumors of deep soft tissues]. / Les tumeurs myxoïdes des tissus mous profonds.

Myxoid soft tissue tumors form a heterogeneous group. Their biological potential encompasses the whole spectrum from benign to highly malignant. The present article focuses on myxoid tumors of the deep soft tissues: myxofibrosarcoma, low-grade fibromyxoid sarcoma, myxoma, myxoid liposarcoma, extraskeletal myxoid chondrosarcoma and nodular fasciitis. The last two decades have brought into practice multiple powerful tools that support pathologists in making precise diagnoses, even on small incisional biopsies: detection of fusion transcripts by rt-PCR, detection of chromosomal fusion or breakpoint by FISH, detection of point mutations by PCR and expression of specific markers by immunohistochemistry. Conventional morphology remains the mainstay of diagnosis, and it is essential to obtain adequate clinical and radiological information before interpreting small incisional biopsies. The present article is a summary of morphologic features used to diagnose the most common tumors of the deep soft tissues.

Low-Grade Surface Osteosarcoma of the Temporal Bone in Paediatric Patients: A Case Report and Literature Review.

PURPOSE OF THE STUDY: Primary osteosarcoma of the temporal bone is an exceedingly rare pathology in the paediatric population. As of now, only 3 cases have been reported in the English literature. We describe the additional case of a 16-year-old girl with an osteosarcoma of the mastoid bone. This study aims to report a rare paediatric case of low-grade surface osteosarcoma of the temporal bone. MATERIALS AND METHODS USED: A literature review was performed to better understand paediatric osteosarcomas of the head and neck region, to optimize their investigation, to describe their histopathological and radiological characteristics, and to establish the optimal modalities of medical and surgical treatments. The research of previous published data was done using PubMed and Embase library with the keywords mentioned below. RESULTS: The patient presented with a rapidly progressive left retroauricular lesion over a 3-week period. Radiological studies demonstrated aggressive and invasive features. An open biopsy followed and confirmed the diagnosis of a low-grade surface osteosarcoma. In accordance with the multidisciplinary team, we decided to perform a complete surgical resection with wide surgical margins. We did not administer any adjuvant therapies. A control computed tomography (CT) scan obtained 26 months postoperatively still showed no signs of recurrence. CONCLUSION: Osteosarcomas are aggressive malignant neoplasms found in the head and neck region in only 6% to 10% of cases. They represent approximately 1% of head and neck cancers, and these are generally high-grade lesions. Temporal bone involvement is rare, particularly for low-grade lesions in paediatric patients. In addition to reporting the fourth paediatric case of primary temporal bone osteosarcoma, this study describes its specific clinical, histopathological, and radiological findings, to improve the management and the prognostic of patients affected with this particular clinical entity.

Cutaneous melanocytoneuroma: the first case of a distinctive intraneural tumor with dual nerve sheath and melanocytic differentiation.

Many melanocytic nevi contain areas similar to nerve sheath tumors (NST) and NSTs with melanin have been described. There are some NSTs with at least partial intraneural location, including neurofibromas, plexiform neurofibromas, granular cell tumors and the recently described, dendritic cell neurofibroma with pseudorosettes. We describe the case of an NST with melanocytic differentiation and intraneural location, for which we suggest the term 'melanocytoneuroma' (MCN). It arose in the skin of a 67-year-old woman with no previous history of melanoma or neurofibromatosis. The lesion presented as a papule and histologically consisted of a dermal nodule without junctional melanocytic activity. The lesion comprised an intraneural proliferation of large epithelioid eosinophilic cells with prominent cell borders imparting a 'plant-like' appearance. The cells were also seen within adjacent nerve twigs and were positive for S100, Melan-A, HMB-45, microphthalmia transcription factor and PGP 9.5. The lesion was entirely surrounded by an epithelial membrane antigen-positive-perineurial coat and the individual tumor cells were invested by laminin and collagen type-IV-positive basal lamina-like material. The lesion did not show any evidence of atypia and following complete excision, no recurrence has been documented. In conclusion, this unusual lesion represents an intraneural proliferation with melanocytic and nerve sheath cell differentiation, to which we have accorded the appellation, MCN.

Predictive factors for sentinel lymph nodes and non-sentinel lymph nodes metastatic involvement: a database study of 1,041 melanoma patients.

BACKGROUND: Sentinel lymph node (SLN) biopsy may identify patients who may need completion lymphadenectomy and adjuvant therapy. METHODS: Univariate and multivariate analysis were conducted for SLN status in a prospective cohort of 1,041 patients. A biopsy was recommended for melanoma greater than or equal to 1 mm thick or greater than or equal to .75 mm with poor prognostic features. RESULTS: For sentinel node status, mitotic rate is very significant in univariate analysis. In multivariate analysis, Breslow, lymphovascular invasion, and primary site were significant. Breslow thickness greater than or equal to 2 mm and SLN with macroscopic burden greater than or equal to 2 mm are the only statistically significant variables predicting the non-SLN status in multivariate analysis. CONCLUSIONS: The data confirm the importance of Breslow, lymphovascular invasion, and body site for SLN status. The cutoff of 2 mm for tumor load in SLN appears to be a simple technique to find the high-risk patients with further lymph node disease.

Intrascrotal extratesticular schwannoma: A first pediatric case.

Scrotal nerve sheath tumours unassociated with neurofibromatosis or schwannomatosis are extremely rare. Very few cases of benign intrascrotal and extratesticular schwannomas have been reported, but none of them occurred in childhood. This current report describes for the first time a case of benign intrascrotal extratesticular solitary schwannoma in a 16-year-old male.

A study of CD117 expression in dermatofibrosarcoma protuberans and cellular dermatofibroma.

BACKGROUND: Dermatofibrosarcoma protuberans (DFSP) is a relatively uncommon spindle cell tumor of the skin. It is locally aggressive and can be a therapeutic challenge. There are case reports of partial response of DFSP to the tyrosine kinase inhibitor STI571 (Imatinib), despite the reported negativity of the tumor cells for CD117. At least one publication reported focal CD117 positivity of DFSP cells, and we would like to clarify the issue. Cellular dermatofibroma (CDF) can mimic DFSP, but typical cases are easily differentiated from DFSP by their staining pattern for CD34 and factor 13a. We also report our experience with CD117 staining of typical CDFs. METHODS: Thirty-seven cases of clear-cut DFSP and 13 cases of clear-cut CDF were retrieved from the archives of Sunnybrook Health Sciences Center between 2000 and 2005. RESULTS: All DFSPs were CD34 (+), factor 13a (-) and CD117 (-). All CDFs were factor 13a (+), CD34 (-) and CD117 (-). CONCLUSIONS: Our study on a relatively large number of cases confirms the negativity of DFSP and CDF for CD117. Therefore, if adjuvant therapy is attempted with drugs such as STI571 (Imatinib), the eligibility of patients should not be based on immunohistochemical assessment of CD117 expression.