Dedifferentiated liposarcoma with chondroblastic osteosarcomatous dedifferentiation

Retroperitoneal dedifferentiated liposarcoma with osteosarcomatous dedifferentiation

We present a case of a dedifferentiated liposarcoma with osteosarcomatous degeneration in a 46-year-old male. The mass, palpated during a routine physical exam, was analyzed with dynamic, contrast-enhanced CT and CT-guided core-needle biopsy before surgical resection.

Dedifferentiated liposarcoma of the neck: CT findings

We report a case of DDL with an osteosarcomatous component affecting the right neck. CT showed a lipomatous region with thick septa, a low-attenuation high-water-content component, and a sporadic heterogeneous high-attenuation calcified area.

Primary (de novo) dedifferentiated liposarcoma in the extremities: a multi-institution Tohoku Musculoskeletal Tumor Society study of 18 cases in northern Japan

OBJECTIVE

Dedifferentiated liposarcomas usually occur in the retroperitoneal space and relatively rarely in the extremities.

METHODS

We identified 18 patients with primary dedifferentiated liposarcoma in the extremities from the files of Tohoku Musculoskeletal Tumor Society and analyzed demographics, histologic findings, treatments and prognostic factors. The average follow-up period was 58 months.

RESULTS

The subjects were 12 men and 6 women with a mean age of 65 years. All tumors were in the thigh. Nine patients noticed a rapid enlargement of the long-standing tumor. Histologic subtypes of the dedifferentiated area were undifferentiated pleomorphic sarcoma (n = 12), osteosarcoma (n = 2), rhabdomyosarcoma (n = 2), leiomyosarcoma (n = 1) and malignant peripheral nerve sheath tumor (n = 1). In the patient with rhabdomyosarcoma-like dedifferentiated area, extensive necrosis was observed after the preoperative chemotherapy. One patient who underwent marginal excision developed a local recurrence, but inadequate surgical margin was not associated with a risk of local recurrence. Three patients had lung metastasis at initial presentation, and four other patients developed lung metastases during the follow-up period. The overall survival rate was 61.1% at 5 years. On univariate analyses, large size of the dedifferentiated area (>8 cm), high MIB-1-labeling index (>30%) for the dedifferentiated area and lung metastasis at initial presentation were significantly associated with poor prognosis.

CONCLUSIONS

Primary dedifferentiated liposarcoma in the extremities predominantly occurred in the thigh and a rapid enlargement of long-standing tumors was a characteristic symptom. Although the local behavior of these tumors was less aggressive than that of retroperitoneal dedifferentiated liposarcomas, they had a relatively high metastatic potential.

Well-differentiated liposarcoma with low-grade osteosarcomatous component: an underrecognized variant

Mature bone formation in well-differentiated liposarcoma and dedifferentiated liposarcoma has been described as a reactive or "metaplastic" change in most reports, and its neoplastic nature has not been widely appreciated. We herein describe 9 cases of well-differentiated/dedifferentiated liposarcoma with distinct areas of fibroosseous tissue histologically indistinguishable from low-grade osteosarcomas, that is, parosteal osteosarcoma or low-grade central osteosarcoma. The tumors affected middle-aged to elderly patients, and occurred in the retroperitoneum and deep soft tissue of the extremities without connection to the skeletal system. Grossly, all the tumors showed biphasic appearance with lipogenic and osteogenic area, the latter representing 5% to 50% of the total tumor volume. Histologically, the lipogenic component exhibited typical histology of well-differentiated liposarcoma, whereas the osteogenic area consisted of fibroosseous tissue with numerous mature neoplastic bone trabeculae largely lacking osteoblastic rimming, with intervening fascicles of spindle cell proliferation showing low nuclear grade. All samples were positive for MDM2 and/or CDK4 on immunohistochemical analysis; the antibodies stained many osteocytes, indicating that the bone is neoplastic rather than reactive. Three cases showed high-grade osteosarcomatous transformation juxtaposed to the low-grade osteosarcomatous component, reminiscent of the "dedifferentiation" phenomenon of skeletal low-grade osteosarcoma. Follow-up revealed local recurrence in 4 cases, but no distant metastases were documented. Recognition of this earlier underappreciated subtype of well-differentiated/dedifferentiated liposarcoma is important, because the fibroosseous component may seem so bland that it may be confused with benign metaplasia such as myositis ossificans, or conversely, the lipomatous component may be inconspicuous that it may be dismissed as normal fat, and such misinterpretation may potentially result in suboptimal treatment.

Dedifferentiated parosteal osteosarcoma with well-differentiated metastases

Metastases of dedifferentiated sarcoma usually contain a dedifferentiated component. We report a rare case of dedifferentiated parosteal osteosarcoma (dd-POS) with well-differentiated multiple metastases in a 65-year-old woman with a painful firm mass on her thigh. Radiological examination revealed that the mass arose from the surface of her femur without medullary involvement. Multiple intramuscular metastases were detected in her lower leg on MR imaging. Small subcutaneous palpable masses were identified on her left lower leg, buttock, chest wall and head. An open biopsy and above-the-knee amputation were performed, and the mass on her femur was diagnosed as a dd-POS. However, histological examination on the subcutaneous lesions in her lower leg, buttock and head showed low-grade conventional POS without dedifferentiated components. To the best of our knowledge, this is the first report of a dd-POS with multiple metastases that do not contain any dedifferentiated components.

Dedifferentiated liposarcoma of the oral cavity with angiosarcomatous dedifferentiation

We report a unique case of a 42-year-old woman with a dedifferentiated liposarcoma of the soft tissue of the oral cavity with angiosarcomatous dedifferentiation. Liposarcomas compromising the head and neck region are very unusual, and most of the cases in oral cavity show a well-differentiated pattern. Dedifferentiation in liposarcomas occurs in about 10% of the cases and, when it occurs, the dedifferentiated areas usually resemble high-grade fibrosarcoma or pleomorphic sarcoma. Divergent differentiation might also occur. To the best of our knowledge, there are only nine cases of dedifferentiated liposarcoma of the oral cavity, none of which show an angiosarcomatous dedifferentiation.

Dedifferentiated Liposarcoma With a Paraganglioma-like Histologic Pattern: A Case Report and Review of the Literature

A 53-year-old man presented with a 4-month history of increasing abdominal discomfort and distension. A large retroperitoneal mass was found on imaging. Image-guided needle core biopsy demonstrated a poorly differentiated malignant neoplasm. A 30 × 32 × 33-cm soft tissue mass was removed. Microscopically, the tumor consisted of predominantly epithelioid malignant cells arranged in a paraganglioma-like growth pattern. Immunohistochemically, these cells were strongly positive for neuron-specific enolase. Stains for synaptophysin and chromogranin, however, were negative. There was no ultrastructural evidence of neuroendocrine differentiation. Adjacent sarcomatous areas were composed of spindled cells arranged in storiform and fibrosarcoma-like growth patterns. A small area of well-differentiated liposarcoma was identified, and a diagnosis of dedifferentiated liposarcoma was established. To the best of our knowledge, this represents the first reported case of dedifferentiated liposarcoma with a paraganglioma-like histologic pattern. A brief review focusing on the morphologic variations of dedifferentiated liposarcoma is also presented.

Low-grade liposarcoma with osteosarcomatous dedifferentiation: radiological and histological features

We describe the radiological and pathological findings of a rare case of a low-grade liposarcoma associated with a high-grade osteosarcomatous component in a 78-year-old woman. Pre-operative imaging demonstrated a well-encapsulated homogeneous fatty tumour in the right buttock deep to the gluteal musculature. Centrally within the fatty tumour a region of increased soft tissue attenuation on CT and heterogeneous high signal on fat-saturated T2-weighted MRI was seen with amorphous calcification/ossification. Histological assessment revealed a low-grade liposarcoma containing an area of dedifferentiation that resembled an osteosarcoma. We describe the radiological-pathological findings in this rarely reported clinical entity and discuss the differential diagnosis of calcification within lipomatous tumours.

Post-radiation dedifferentiation of meningioma into osteosarcoma

BACKGROUND

A number of osteoblastic meningiomas, primary osteosarcomas of the meninges, and post-radiation osteosarcomas of the head have been reported. However, postradiation dedifferentiation of meningioma into osteosarcoma has not been reported previously.

CASE PRESENTATION

In 1987 a caucasian man, then 38 years old, presented with a pituitary macroadenoma. He underwent a subtotal resection of the tumor and did well until 1990 when a recurrent tumor was diagnosed. This was treated with subtotal resection of the tumor, followed by radiation therapy for six weeks to a total of 54 Gy. He was considered "disease-free" for nearly ten years. However, most recently in July 2000, he presented with a visual field deficit due to a second recurrence of his pituitary macroadenoma, now with suprasellar extension. At this time, as an incidental finding, a mass attached to the dura was noted in the left parietal hemisphere. This dura-based mass had grown rapidly by January 2001 and was excised. It showed histological, immunohistochemical, and electron microscopic features of malignant meningioma and osteosarcoma with a sharp demarcation between the two components.

CONCLUSIONS

We report a rare case of a radiation induced dedifferentiation of meningioma into osteosarcoma, which has not been reported previously.