Well-differentiated liposarcoma of the retroperitoneum: a clinicopathologic analysis of 20 cases, with particular attention to the extent of low-grade dedifferentiation.
Malignant transformation of a benign lipoma to malignant liposarcoma is practically unknown.8 It is crucial that the diagnosis of a
well-differentiated liposarcoma is established preoperatively, because there are differences in initial treatment, longterm management and prognosis.
(4) The incidence of liposarcoma in the hypopharynx is not well-reported in the literature, with less than 40 cases reported, almost all of which are
well-differentiated liposarcoma. (5,6)
The value of fat-suppressed T2 or STIR sequences in distinguishing lipoma from
well-differentiated liposarcoma. Eur Radiol.
CT appearance of a
well-differentiated liposarcoma may be very similar to the remnants of infiltrated soft tissue [10].
Eward et al., "Can experienced observers differentiate between lipoma and
well-differentiated liposarcoma using only MRI?," Sarcoma, vol.
Caption: Figure 3: Histology of the primary site-dedifferentiated liposarcoma (a, b) and
well-differentiated liposarcoma components (c, d) and the metastasis (e, f).
It is noteworthy that imaging features of lipomas can be similar to
well-differentiated liposarcomas. Presence of imaging features such as thick enhancing septa, presence of nodular and/or globular, or nonadipose mass like areas and decreased percentage of fat within the lesion are suggestive of malignancy [7].
The histopathologic exam showed a
well-differentiated liposarcoma with spindle and lipoma-like cells (Grade 1), without infiltration of the testis and with free surgical margins.
Common types of liposarcoma include
well-differentiated liposarcoma, myxoid, dedifferentiated, and pleomorphic liposarcoma.
One case each of malignant fibrous histiocytoma, myxoid liposarcoma [Figure 1b], atypical lipomatous tumor/
well-differentiated liposarcoma (ALT/WDL), and malignant mesothelioma were identified.
[sup][4] Liposarcomas were divided into the following five subtypes:
well-differentiated liposarcoma, dedifferentiated liposarcoma, myxoid liposarcoma, pleomorphic liposarcoma, and mixed liposarcoma.