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Osteogenic differentiation in dedifferentiated liposarcoma: a study of 36 cases in comparison to the cases without ossification
Author(s) -
Yamashita Kyoko,
Kohashi Kenichi,
Yamada Yuichi,
Ishii Takeaki,
Nishida Yoshihiro,
Urakawa Hiroshi,
Ito Ichiro,
Takahashi Mitsuru,
Inoue Takeshi,
Ito Masafumi,
Ohara Yuuki,
Oda Yoshinao,
Toyokuni Shinya
Publication year - 2018
Publication title -
histopathology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.626
H-Index - 124
eISSN - 1365-2559
pISSN - 0309-0167
DOI - 10.1111/his.13421
Subject(s) - ossification , liposarcoma , pathology , osteosarcoma , grading (engineering) , heterotopic ossification , medicine , biology , sarcoma , anatomy , ecology
Aims Ossification is found occasionally in dedifferentiated liposarcoma ( DDLPS ). The aims of this study were to elucidate whether the formed bone tissue is usually produced by tumour cells or by reactive non‐neoplastic cells, and to reveal the clinicopathological characteristics of DDLPS with ossification. Methods and results We examined 36 cases of ossified DDLPS by comparing them to 31 cases of non‐ossified DDLPS . MDM 2 amplification was confirmed in osteocytes and/or osteoblastic cells in all but one ossified DDLPS cases (27 of 28) using fluorescence in‐situ hybridisation, although the morphological impression of ossification appeared to be mainly metaplastic (27 of 36) or high‐grade osteosarcoma‐like (six of 36). The bone tissue was often formed predominantly at the periphery of the DDLPS area near the well‐differentiated liposarcoma component (18 of 36), and an organised structure such as bone marrow‐like differentiation was not uncommon (12 of 36). According to a modified French Fédération Nationale des Centers de Lutte Contre le Cancer ( FNCLCC ) grading system, ossified DDLPS tended to be lower grade than non‐ossified DDLPS (mean grade: 1.88 and 2.15, respectively). Ossification in DDLPS was associated significantly with shorter local recurrence‐free survival by multivariate analysis ( P = 0.02347), but metaplastic‐appearing ossification tended to be associated with longer overall survival ( P = 0.1400). Conclusions The bone tissue formed in DDLPS was mainly neoplastic regardless of its morphology and maturity, which highlighted the osteogenic differentiation of the tumour cells. DDLPS patients with osteogenic differentiation tended to suffer from earlier local recurrences, which did not necessarily lead to poor life outcomes.