This issue of the American Journal of Surgical Pathology: Reports and Reviews is centered around challenging diagnostic issues in tumors of bone and soft tissue. In keeping with the journal's mission of promoting education for both practicing pathologists and trainees, this issue features several focused review articles written by international experts along with a variety of case reports designed to highlight unusual presentations of well-described entities. The topics are particularly timely, given the recent publication of the fifth edition of the World Health Organization Classification of Soft Tissue and Bone Tumors.
First, the issue features review articles highlighting common differential diagnostic issues in soft tissue and bone pathology, by Drs Behtaj and Rosenberg, respectively. These articles feature a clear and concise discussion of commonly encountered entities, with extensive radiographic and histologic illustrations. Next we include several unique case reports of soft tissue tumors, including an unusual primary alveolar soft part sarcoma by Aggrawal et al, an uncommon example of dedifferentiated solitary fibrous tumor by Roitman et al, and an inflammatory myofibroblastic tumor by Barbieri et al. Also included is a brief description of a pleomorphic liposarcoma by Hariri et al, of interest for varying background patterns, which are easy to mistake for less aggressive sarcomas, particularly on biopsies. The discussion continues onto the entity of rhabdomyosarcomas, with a case report by Wessinger et al, and concludes with a review of the updated classification of rhabdomyosarcoma, including novel molecular subtypes, by Dashti et al.
Our discussion of unique bone tumors features a challenging case of malignant diffuse tenosynovial giant cell tumor by MacMahon et al, an unexpected presentation of chondromyxoid fibroma by Singh et al, and a rare example of polyostotic fibrous dysplasia with extensive cartilaginous differentiation by Hakar et al. Bone and soft tissue lesions are relatively uncommon and can feature significant histologic overlap between entities (often with divergent prognoses and therapies), posing diagnostic challenges for general pathologists and subspecialists alike. The cases and reviews included in this issue are intended to clarify these differences, with an eye toward the newly revised fifth edition of the World Health Organization, and illustrate the importance of careful clinical and radiographic correlation (which is of particular importance in this subspecialty). We are deeply grateful to the authors for their contributions to this issue and for helping us continue the mission of pathology education.