Predictors of survival after resection of retroperitoneal sarcoma, the pathologist point of view

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Retroperitoneal liposarcoma : current insights in diagnosis and treatment

Retroperitoneal liposarcoma (RLS) are rare, biologically heterogeneous tumors that present considerable challenges due to their size and deep location. As a consequence, the majority of patients with high grade RLS will develop locally recurrent disease following surgery, and this constitutes the cause of death in most patients. Here, we review current insights and controversies regarding histology, molecular biology, extent of surgery, (neo)adjuvant treatment, and systemic treatment including novel targeted agents in RLS

The rapidly expanding group of RB1-deleted soft tissue tumors : an updated review

The classification of soft tissue tumors has evolved considerably in the last decade, largely due to advances in understanding the pathogenetic basis of many of these, sometimes rare, tumors. Deletion of Retinoblastoma 1 (RB1), a well-known tumor suppressor gene, has been implicated in the tumorigenesis of a particular group of soft tissue neoplasms. This group of so-called "RB1-deleted soft tissue tumors" has been rapidly expanding in recent years, currently consisting of spindle cell/pleomorphic lipoma, atypical spindle cell/pleomorphic lipomatous tumor, pleomorphic liposarcoma, myofibroblastoma, cellular angiofibroma, and acral fibromyxoma. Most of these neoplasms, except pleomorphic liposarcoma, are considered benign entities and are mainly described in the older adult population. This article will review the currently known morphological, immunohistochemical, and molecular features of this heterogeneous group of mesenchymal tumors with an emphasis on differential diagnosis

Multifocal cytokeratin expression in a dedifferentiated solitary fibrous tumor with heterologous rhabdomyosarcomatous differentiation : a challenging diagnosis!

We report the case of a dedifferentiated solitary fibrous tumor with heterologous rhabdomyosarcomatous differentiation in a 74-year-old male presenting with a rapidly growing, large soft tissue tumoral mass in the gluteal muscles of the right hip. Dedifferentiation in solitary fibrous tumor had not been recognized until very recently and is an extremely rare phenomenon in this tumor type. In the present case, the diagnosis of dedifferentiated solitary fibrous tumor was difficult because of the absence of areas of conventional solitary fibrous tumor with a predominantly poorly differentiated, anaplastic tumor component in the incision biopsy composed of heterogeneous areas with small blue round cell (Ewing sarcoma-like), rhabdoid, epithelioid, and pleomorphic morphology. Moreover, the unforeseen strong patchy to multifocal positivity for cytokeratin AE1/AE3 and desmin made the diagnosis of a dedifferentiated solitary fibrous tumor even more challenging in this case. The morphology (presence of branching thin-walled, hemangiopericytoma-like blood vessels) and the immunohistochemical profile (including STAT6 and GRIA2 positivity) were very useful to differentiate this very challenging case of a cytokeratin-positive dedifferentiated solitary fibrous tumor with heterologous rhabdomyosarcomatous differentiation from a broad list of differential diagnoses