The evolving classification of soft tissue tumours – an update based on the new 2013 WHO classification

Abstract

The new World Health Organization (WHO) classification of soft tissue tumours was published in early 2013, almost 11 years after the previous edition. While the number of newly recognized entities included for the first time is fewer than that in 2002, there have instead been substantial steps forward in molecular genetic and cytogenetic characterization of this family of tumours, leading to more reproducible diagnosis, a more meaningful classification scheme and providing new insights regarding pathogenesis, which previously has been obscure in most of these lesions. This brief overview summarizes changes in the classification in each of the broad categories of soft tissue tumour (adipocytic, fibroblastic, etc.) and also provides a short summary of newer genetic data which have been incorporated in the WHO classification.

Recurrence of a de-differentiated liposarcoma of the colon

“…New genetic and molecular data for established tumour types were included as they facilitated improved pathological definition and diagnosis. [2] Interestingly, tumours previously classified as "mixed-type liposarcoma" are now considered unusual examples of dedifferentiated liposarcoma.…”

Sclerosing Rhabdomyosarcoma: Presentation of a Rare Sarcoma Mimicking Myoepithelial Carcinoma of the Parotid Gland and Review of the Literature

“…However, the difference in age distribution and unique appearance raised concerns about this categorization. Currently, the new 4th edition of the WHO classification of Tumors of Soft Tissue and Bone created a provisional category combining SRMS with spindle cell rhabdomyosarcoma (which was also previously included under embryonal rhabdomyosarcoma) [22]. The basis for this recategorization appears to be mainly a result of morphologic overlap between these variants [2,8,13,15,17,23].…”

“…Since these early reports a total of 42 cases of SRMS have been described in the English literature of which 22 have occurred in adults (C18 years old) [2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18][19][20]. From the limited number of cases of this rare malignancy, it appears that SRMS has a predilection for the extremities and the head and neck.…”

Thigh Pain in an 18-year-old Man

“…The clinical presentation of Langerhans cell histiocytosis may vary from a solitary lesion of bone to a fulminant systemic involvement (Hand-Schüller-Christian disease and Letterer-Siwe disease) [19]. The World Health Organization 2013 guidelines [6] prefer the use of the term Langerhans cell histiocytosis; however, the term eosinophilic granuloma often is used when the disease is limited to bone or lung. Bone involvement occurs in the majority of patients and can involve any bone of the body; monostotic disease is more common than polyostotic involvement.…”