Radiation-associated extraskeletal osteosarcoma of the chest wall

Radiation-associated sarcoma is a rare but potential complication of radiation therapy. Most reported cases of osteosarcoma of the chest wall following radiation therapy for breast cancer arise from the chest wall skeletal structures. In contrast, few cases of extraskeletal osteosarcomas have been reported. We report a rare example of an extraskeletal osteosarcoma involving the pectoralis major muscle occurring after radiation therapy for breast cancer. Extraskeletal osteosarcomas are rare soft tissue tumors with a high rate of local recurrence and a poor prognosis.     

Low-grade extraskeletal osteosarcoma of the mediastinum: report of a case and review of literature

Extraskeletal osteosarcoma (ESOS) is a rare soft tissue sarcoma, typically characterized by a bone-producing neoplasm. Low-grade extraskeletal osteosarcoma (LGESOS) is an extremely rare soft tissue tumor, and patients with LGESOS tend to have a better prognosis. Here, we reported a case of LGESOS of the mediastinum with lung metastasis, and describe its clinical, pathological and radiological features, and compared them with those of the reported cases.     

Extraskeletal osteosarcoma histologically mimicking parosteal osteosarcoma

An extraskeletal osteosarcoma histologically mimicking parosteal osteosarcoma arising in a 63-year-old female is described. The intramuscular lesion in the left lower thigh was a 7 x 4 cm, well-defined mass with marked central calcification and ossification. The tumor was composed predominately of a centrally located osteocartilaginous component and a peripheral, non-osseous fibrous component. The former was characterized by a complex interanastomosing pattern of woven-bone trabeculae with small osteocytes and a minor cartilaginous element. The intratrabecular stroma consisted of benign-appearing fibroblasts. The peripheral fibrous part was characterized by fascicular and interlacing proliferations of spindle cells with mild atypia, rare mitosis and low to moderate cellularity. There were a few scattered foci of proliferating pleomorphic cells, constituting 5% of the tumor, indicating high-grade transformation. There was no evidence of zoning phenomena, cortical erosion, periosteal reaction or intramedullary involvement. The patient is well without recurrence or metastasis at 12 months follow up. This soft tissue neoplasm, mimicking parosteal osteosarcoma, should be distinguished from other bone-forming tumors or tumor-like lesions with which they may be confused. Pathologists and physicians should know the existence of this type of extraskeletal osteosarcoma and treat it as a high-grade extraskeletal osteosarcoma.     

Small-cell extraskeletal osteosarcoma: case report and literature review

Small-cell extraskeletal osteosarcoma is extremely rare and consists of sheets of small round cells with variable amounts of osteoid. This tumor is often difficult to diagnose when tissue samples do not include recognizable osteoid. Only four cases have been reported in English and none in Chinese. We report a typical case of small-cell extraskeletal osteosarcoma occurring in the left leg of a 40-year-old female. Laboratory results were within normal limits. Magnetic resonance imaging demonstrated a soft tissue mass measuring 36 mm × 18 mm in the medial lateral aspect of left limb. The initial histological findings led to a misdiagnosis because the first fine-needle biopsy was randomized and incomplete. However, an open surgical specimen showed recognizable osteoid, which enabled us to make a definitive diagnosis. We also present clinical, radiologic and pathologic features of this case.     

Scrape and fine-needle aspiration cytology of extraskeletal osteosarcoma

Extraskeletal osteosarcoma is a rare malignant soft tissue tumor whose cytologic findings are infrequently reported. We describe scrape and fine-needle aspiration biopsy (FNAB) cytology findings of an extraskeletal osteosarcoma in the right shoulder of a 24-yr-old man. Initial computed tomography revealed multiple ossification foci within the lesion. After excision of the primary tumor, the tumor recurred 13 months later. Scrape smears of both the primary tumor and FNAB smears of the recurrent tumor revealed moderate cellularity, cell clusters, and individual cells, closely associated with dense, homogeneous, acellular matrix material. The cells had elongated, oval, or partially bizarre-shaped nuclei with a coarse chromatin pattern and prominent nucleoli. The scrape smears contained large fragments of matrix material consistent with osteoid.     

Well-differentiated extraskeletal osteosarcoma. A soft-tissue homologue of parosteal osteosarcoma

We describe a unique case of a low-grade extraskeletal osteosarcoma revealing both histologic and radiologic features reminiscent of parosteal osteosarcoma. The tumor, which had been present for 10 years, occurred in the left axilla of a 74-year-old black woman. To date, all the published cases of extraskeletal osteosarcoma have been high-grade neoplasms; to our knowledge, this is the first reported case of a low-grade extraskeletal osteosarcoma.     

Aggressive (epithelioid) osteoblastoma arising in soft tissue

Aggressive (epithelioid) osteoblastoma arising in soft tissue has never been described. It is important to differentiate this benign osteoblastoma, a potentially locally aggressive tumor, from extraskeletal osteosarcoma. This report describes an aggressive (epithelioid) osteoblastoma arising in a focus of heterotopic ossification in the axilla of a 21-year-old man.     

Extraskeletal osteogenic sarcoma: a rare entity

A 25-year-old female presented with a rapidly increasing painful swelling around right lower thigh and knee for the last 5 months with distant metastasis in the form of lung involvement. X-ray of the part showed only soft tissue swelling without any bony involvement. A diagnosis of extraskeletal osteosarcoma was made which was confirmed by immunohistochemistry.     

Immunohistochemical and FISH analysis of MDM2 and CDK4 in a dedifferentiated extraskeletal osteosarcoma arising in the vastus lateralis muscle: Differential diagnosis and diagnostic algorithm

Extraskeletal osteosarcoma is a rare neoplasia within the broad differential diagnostic spectrum of calcifying intramuscular lesions. We present a case of a slowly increasing mass within the left vastus lateralis muscle. At first presentation the patient showed a partially calcified well defined mass with a diameter of 5 cm and with no direct contact to the femur. A biopsy from the periphery revealed an ossifying lesion compatible with myositis ossificans. The patient returned 18 months later with the lesion having increased to a diameter of 25 cm. The resection specimen revealed a well delimitated tumor with a central core of partially necrotic neoplastic bone. Besides, histology showed high mitotic areas with pleomorphic spindle cells and regions with cartilaginous differentiation. Immunohistochemistry demonstrated: vimentin+, CD34−, desmin−, actin−, EMA− and pancytokeratin− with focal S100 protein positivity and a Ki-67 index of 20%. Comparative genomic hybridization (CGH) revealed a gain of chromosomal material on 12q; FISH analyses for the CDK4 and MDM2 region showed high level amplifications. Consequently, a high-grade dedifferentiated extraskeletal osteosarcoma was diagnosed. In conclusion, analysis of the MDM2 and CDK4 status is a powerful and discriminating diagnostic tool to distinguish dedifferentiated extraskeletal osteosarcoma from other benign/malignant ossifying lesions in the skeletal muscle.     

Extraskeletal osteosarcoma of the scalp

A rare case of extraskeletal osteosarcoma of the scalp in a 56-year-old woman is described. At presentation she was found to have an 8-cm diameter, tender, firm, exophytic scalp tumor. MRI scan confirmed absence of underlying skeletal origin and showed extension along the subcutaneous plane. The tumor was excised and the patient received post-operative chemotherapy. Histologically, the tumor showed classical features of an osteogenic osteosarcoma with focal fibroblastic areas. In addition, there were rhabdoid cells present, which showed paranuclear cytoplasmic immunoreactivity for epithelial membrane antigen. The patient developed metastatic disease 6 months after surgical excision.     

Extraskeletal osteosarcoma with cystic appearance in an aged Sprague-Dawley rat

Extraskeletal osteosarcoma, arising spontaneously from the subcutis of the left abdomen and having a cystic appearance, was found in an untreated male Sprague-Dawley rat during a carcinogenicity study. At 76 weeks of age, the tumor mass had grown to 50 x 110 x 140 mm, and the animal exhibited severe anemia related to the complication of ulceration with hemorrhage. The tumor displayed irregular ossification at the walls of a cyst-like space filled with much yellowish fluid and necrotic cellular debris. Histopathologically, the tumor consisted of sheets of large, plump osteoblast-like cells, which produced broad irregular trabeculae of osteoid and calcified osseous tissue. Since extraskeletal osteosarcoma with a cystic appearance, has not been reported in animals, except for the telangiectatic type, our case shows an extremely rare type.     

Cartilage-forming tumours of bone and soft tissue and their differential diagnosis

The prevalence of primary malignant bone tumours is estimated to be 1:100,000 within the general population: 17–24% of these are malignant cartilaginous tumours (chondrosarcomas). The incidence of benign bone tumours is largely unknown, due to lack of registration as well as frequent failure to present clinically. Benign cartilaginous tumours of bone include chondroma, osteochondroma, chondroblastoma and chondromyxoid fibroma, whereas among the malignant cartilaginous bone tumours conventional, juxtacortical, mesenchymal, dedifferentiated, and clear cell chondrosarcomas are recognized. The histological distinction between the different entities is based on cell type/differentiation, matrix formation and architecture, combined with radiodiagnostic and clinical data. Extraskeletal cartilaginous lesions are extremely uncommon and include soft tissue chondroma, mesenchymal and extraskeletal myxoid chondrosarcoma. The formation of cartilaginous matrix can be found in many other non-cartilaginous tumours (such as periosteal osteosarcoma and chondroblastic osteosarcoma) and tumour-like lesions (such as fibrous dysplasia, Nora's lesion, primary synovial chondromatosis, dysplasia epiphysealis hemimelica and callus formation) These conditions may lead to an erroneous diagnosis of a primary osseous cartilaginous tumour.     

Fibro-osseous pseudotumor of the digits arising in the subungual region: A rare benign lesion simulating extraskeletal osteosarcoma

A rare case of subungual fibro-osseous pseudotumor of the digits in a 59 year old woman is reported. A painful polypoid mass with ulcerative changes was noted in the subungual portion of the right first toe. Macroscopically, the tumor arose chiefly in the subcutaneous region and was unrelated to the underlying bone tissue. Histologically, the lesion contained fibroblast-like tumor cells producing an extensive osteoid substance in a granulation-like background. Although it was necessary to distinguish the lesion from extraskeletal osteosarcoma, the tumor cells lacked prominent atypical features. It is considered that pathologists and clinicians should add fibro-osseous pseudotumor of the digits to the differential diagnosis of subungual tumor.     

High-grade extraskeletal myxoid chondrosarcoma: a high-grade epithelioid malignancy

AIMS: Extraskeletal myxoid chondrosarcoma is typically a low-to-intermediate grade sarcoma that is associated with a prolonged clinical course. High-grade forms are rare and not well characterized. In this series we report the clinicopathological, immunohistochemical and ultrastructural findings in four cases of high-grade extraskeletal myxoid chondrosarcoma. METHODS AND RESULTS: The patients were three men and one woman (ages 34-73 years) with tumours located in the thigh (two cases), paraspinal soft tissue and perineum. Three patients had metastases, one at 12 weeks, one at 10 months, and one at presentation of recurrent tumour. In the latter case the original tumour was low grade and became high grade when it recurred 3.5 years later. All three patients died of disease. One patient was lost to follow-up. The most striking histological feature in all four tumours was the presence of numerous large epithelioid cells. These cells were arranged in cords within myxoid matrix and in sheets devoid of matrix. Two tumours had areas of conventional extraskeletal myxoid chondrosarcoma intermixed with the high-grade areas. One tumour showed transition to high-grade spindle cell sarcoma. One tumour had cells with rhabdoid features. Immunohistochemically, two tumours focally expressed S100 protein, and one focally expressed EMA. All were negative with cytokeratin, desmin, smooth muscle actin, HMB45, CD31 and CD34. Ultrastructural features in three cases were compatible with chondrosarcoma; one tumour had aggregates of microtubules within rough endoplasmic reticulum, a characteristic feature of this tumour. CONCLUSIONS: High-grade extraskeletal myxoid chondrosaroma is a rare and aggressive soft tissue sarcoma, and should be included in the differential diagnosis of other epithelioid malignancies.     

Soft tissue sarcomas apparently arising in chronic tropical ulcers

Of 720 soft tissue sarcomas received from Malawi over a 15 year period, eight had apparently arisen in chronic tropical ulcers which are endemic in that part of Africa. These eight tumours were classified as leiomyosarcoma (three), extraskeletal osteosarcoma (two), malignant fibrous histiocytoma (one), myxoid liposarcoma (one) and unclassifiable (one). All had a history suggestive of malignant change in a long-standing ulcer, in each case clinically thought to be a squamous carcinoma. However, in none was there evidence of an epithelial origin and all were negative for epithelial membrane antigen and cytokeratin. This association has not previously been reported. The validity of this proposed association is discussed.     

Extraskeletal myxoid chondrosarcoma: multimodal diagnosis and identification of a new cytogenetic subgroup characterized by t(9;17)(q22;q11)

Extraskeletal myxoid chondrosarcoma is a rare malignant soft tissue tumour that can be difficult to diagnose correctly, especially preoperatively. We describe four cases of extraskeletal myxoid chondrosarcoma of the extremities diagnosed by a multimodal approach. The cytological examination of fine-needle aspirates showed small and round, mildly pleomorphic cells lying in sheets and cords, but also dispersed within a myxoid and metachromatic intercellular substance. Histological, electron microscopic and immunocytochemical examination also yielded findings compatible with the diagnosis of extraskeletal myxoid chondrosarcoma. Cytogenetic analysis demonstrated a t(9;22)(q22;q12) in two tumours and a t(9;17)(q22;q11) in the third and fourth. The translocation t(9;22)(q22;q12) has been described repeatedly in extraskeletal myxoid chondrosarcoma but never in other tumours; hence, the detection of this pathognomonic chromosome abnormality in short-term cultured cells from fine-needle aspirates verified the diagnosis in two of the cases. The t(9;17)(q22;q11) found in the last two cases probably represents a new cytogenetic subgroup of extraskeletal myxoid chondrosarcoma as it, too, is unknown in other contexts. The multimodal approach taken in these four cases enabled a definite diagnosis of a rare malignant tumour whose cytological and histological features alone are usually not sufficiently distinct to rule out other differential diagnostic possibilities. Received: 16 March 1999 / Accepted: 1 June 1999     

Retroperitoneal extraskeletal myxoid chondrosarcoma

INTRODUCTION: Extraskeletal myxoid chondrosarcoma is a rare soft tissue tumor included by WHO in the group of tumors of uncertain differentiation because well formed cartilage is rarely seen in its setting; moreover some of the immunophenotype features of the tumor are still controversial. The reciprocal translocation t(9;22)(q22;q12) has recently been identified in many cases, and this chromosomal aberration is currently considered high specific of this tumor. CASE REPORT: We report the case of a 75-year-old female submitted to radical nephrectomy for a voluminous kidney tumor with radiological evidence of extrarenal extension. RESULTS: Grossly the lesion was set in the perirenal fat tissue. Histological examination revealed a malignant mesenchimal tumor with myxoid f eatures and areas of chondroid differentiation consistent with the diagnosis of extraskeletal myxoid chondrosarcoma. According with the diagnosis the tumor showed focal positivity to NSE by immunohistochemistry. DISCUSSION: Differentiated cartilage is seen in extraskeletal myxoid chondrosarcoma in about 30% of the cases. Our case is then interesting not only for the rare site of tumor location but also for the extension of chondroid differentiation areas found on histologic examination in the tumor setting. Moreover immunohistochemistry showed focal positivity of the neoplastic cells for NSE, according with recent studies demonstrating expression of some neural/neuroendocrine markers in extrascheletal myxoid chondrosarcoma.     

Periosteal osteosarcoma of the femur with bone marrow involvement: A case report

Periosteal osteosarcoma is an exceedingly rare type of chondroblastic osteosarcoma, showing rather better prognosis, and secondary bone marrow involvement is unusual. A case of a 22 year old male with periosteal osteosarcoma of the right femur with an associated bone marrow lesion is presented. The juxtacortical tumor, 16 ×11 × 9 cm, was located on the bone cortex of the upper diaphysis and extended into the surrounding soft tissues. A minimal bone marrow lesion was present, although the bone cortex was quite intact. Microscopically, the tumor consisted exclusively of atypical chondroblastic cells with a small osteoblastic area. The bone marrow lesion, interestingly, contained both multiple nodules of well-differentiated chondrosarcomatous components and a few demarcated foci of atypical spindle cells producing a fine osteoid matrix. It was reasonable to conclude, therefore, that this tumor was a periosteal osteosarcoma with an unusual secondary bone marrow lesion rather than a conventional (central) chondroblastic osteosarcoma with soft tissue invasion. The patients good prognosis with no tumor recurrence or metastasis during more than 7 years follow-up after surgery supports this conclusion.