Extraskeletal osteosarcoma arising in the buttock

Primary cutaneous extraskeletal osteosarcoma: a series of 16 cases

Extraskeletal osteosarcoma (EOS) is a high grade soft tissue tumour characterised by the production of malignant osteoid, without attachment/involvement of underlying bone/periosteum. Rarely, EOS presents as a cutaneous tumour. The clinical behaviour of primary cutaneous EOS (PC-EOS) remains incompletely characterised. Herein we present the largest case series of PC-EOS reported to date. Sixteen PC-EOS cases from the archives/consultation files were retrieved (male:female 1:1; age 31-96 years, mean age 66 years). The tumours measured 1-10 cm (mean 3.2 cm) and were located on the lower extremity (7), head (6), upper extremity (2), and trunk (1). They consisted of pleomorphic, spindled-to-epithelioid cells, with fascicular, nodular, or sheet-like growth patterns and foci of malignant osteoid. Immunohistochemistry did not reveal specific lines of differentiation, and there was no evidence of other tumour types. A literature review was conducted to identify all well characterised cases of PC-EOS. A combined analysis of present and past cases was performed to determine overall trends in clinical characteristics and outcomes. The mean follow-up period was 23.9 months, during which 67.5% of patients experienced progression-free survival and 18% of patients died of disease. Rates of local recurrence and metastasis were 10% and 25%, respectively, approximately double past estimates. These data suggest that the prognosis of PC-EOS is less favourable than previously thought. The differential diagnosis includes benign entities (e.g., ossifying pyogenic granuloma) and malignant neoplasms with heterologous osteosarcomatous differentiation (e.g., carcinosarcoma, transdifferentiated melanoma). Wide excision remains the standard of care, and the role of chemotherapy and radiation remains inconclusive. Recognition of this rare entity can facilitate prompt diagnosis and appropriate treatment.

Primary cutaneous extraskeletal osteosarcoma of the pretibial leg: A case report and summary of the literature

Primary cutaneous extraskeletal osteosarcoma is a rare tumor, with fewer than thirty known cases worldwide. We report the case of a 60-year-old female who presented with a solitary 3 mm right pretibial nodule. She had no known comorbidities, trauma to the area, nor prior malignancy. The biopsy specimen showed abundant mineralized osteoid, in which pleomorphic and spindled cells with anaplastic features were embedded. The osteoid matrix in this case contained overtly malignant cells, with frequent mitotic figures, as well as multinucleated giant cells. Immunohistochemistry and imaging led to the conclusion that this nodule represented a primary cutaneous extraskeletal osteosarcoma. The previously reported cases are variable in location, size, gross appearance, and clinical course. The prognosis of osteosarcoma is typically poor, with aggressive behavior; this, however, may be less severe in these strictly cutaneous tumors, though additional follow-up would be beneficial to determine long-term outcomes for the known cases. Ultimately, despite the fact that this is an extremely rare entity, primary cutaneous extraskeletal osteosarcomas should be considered when relevant. This article is protected by copyright. All rights reserved.

Primary cutaneous osteosarcoma of the scalp in an immunosuppressed individual: A case report and review of the literature

We report a case of a 76-year-old man presenting with a 12-month history of a solitary lesion on his scalp. The histopathology was consistent with a grade 2/3 osteosarcoma extending to the subcutis. Full-body imaging excluded any involvement of the underlying bony tissue or solid organ malignancy, thus a diagnosis of primary cutaneous osteosarcoma (PCO) was made. Given the exceedingly rare nature of PCO, we discuss the clinico-pathological features of this case and those previously reported in the literature.

Extraskeletal osteosarcoma arising in the subcutaneous tissue of the lower leg: A case report and literature review

Extraskeletal osteosarcoma (ESOS) is a rare soft tissue sarcoma accounting for 1-2% of all soft tissue sarcomas. ESOS originating in the superficial (cutaneous-subcutaneous) tissue is extremely rare, and only 17 cases with subcutaneous ESOS have been reported in detail to date. The aim of the present study was to report an additional case of subcutaneous ESOS of the lower leg and review previous reports of subcutaneous ESOS, focusing on the clinical characteristics, including the MIB-1 labeling index, treatment methods and outcomes. A 79-year-old healthy man presented with a 3-year history of a painful, slowly growing mass in his right lower leg that measured ~5 cm in greatest dimension. Excisional biopsy was performed, and ESOS was diagnosed based on the histopathological findings. A wide resection was performed when local recurrence developed. Six months after the wide resection, lung metastasis was detected. Considering the patient's age, stereotactic radiotherapy was performed without chemotherapy. The patient showed no evidence of local recurrence or new distant metastases for 2 years after the second surgery. We herein present this case of subcutaneous ESOS and review the previous 17 reported cases of subcutaneous ESOS. The 5-year survival rate of patients with subcutaneous ESOS was 78.6%, which was better compared with that of ESOS cases arising in deep soft tissue. Therefore, patients with subcutaneous ESOS may have a better prognosis compared with those with deep-seated ESOS, although the mean MIB-1 labeling index of subcutaneous ESOS was 24%.

Extra skeletal osteosarcoma of gall bladder: A case report

Extraskeletal osteosarcoma is a rare malignant soft tissue tumor. At open cholecystectomy performed for gallstones, a 45-year-old woman was found to have extraskeletal osteosarcoma on histopathological examination. 1 year after surgery, the patient is symptom free and all imaging studies are normal. After multidisciplinary discussion it was decided to give no further treatment. The patient was asked to follow up three monthly. Although osteosarcoma has rarely been reported at other extraskeletal sites, this appears to be the third case of a primary tumor in the gallbladder.

An abdominal extraskeletal osteosarcoma: A case report

Primary abdominal extraskeletal osteosarcoma (EOS) is a rare carcinoma. The present study reports a case of a primary abdominal EOS involving the greater omentum and also presents a review of the literature on the etiology, diagnosis, differential diagnosis, pathological features, treatment and prognosis of the disease. The patient in the present study underwent laparoscopic surgery. A pathological examination revealed that the tumor tissues contained malignant and primitive spindle cells with varying amounts of neoplastic osteoid and osseous or cartilaginous tissue. The post-operative follow-up appointments were scheduled at three-month intervals for two years. The tumor recurred three months after the surgery.

Extraskeletal subcutaneous osteosarcoma of the upper arm: A case report

Extraskeletal osteosarcoma (ESOS) occurs in approximately 1% of soft tissue sarcomas and 2-4% of all osteosarcomas. In particular, subcutaneous osteosarcoma is extremely rare, occurring in less than 10% of ESOS cases. This report presents a case of a subcutaneous tumor in the upper arm of a 79-year-old male. Imaging and pathological findings led to the conclusion that the soft tissue tumor should be diagnosed as subcutaneous osteosarcoma. Additionally, this case report documented the clinicopathological findings of the extraskeletal subcutaneous osteosarcoma in this case and discussed its clinical features by reviewing cases previously described in the literature.

Osteosarcoma in a patient with neurofibromatosis type 1: a case report and review of the literature

Neurofibromatosis type 1 (NF1) or von Recklinghausen's disease is a genetic disease generally characterized by café-au-lait spots and neurofibromas. Malignant tumors of the nervous system, such as malignant schwannomas, gliomas, or astrocytomas, have been well known to coexist with neurofibromatosis. However, occurrence of malignant tumors unrelated to the nervous system is rare. We report an unusual case of a 29-year-old NF1 female suffering from malignant peripheral nerve sheath tumor (MPNST) that eventually developed osteosarcoma in the proximal femur. Osteosarcoma is the most common high-grade malignant bone tumor in which the neoplastic cells produce osteoid. At 23 and 24 years old, she underwent excision of MPNST in the left posterior thigh. No osteosarcomatous portion was identified in these specimens. The patient underwent postoperative chemotherapy. At 29, left proximal thigh pain and swelling appeared. Computed tomography demonstrated cortical bone destruction in the left proximal femur where MPNST occurred. Magnetic resonance imaging revealed extraskeletal growth of the tumor. Bone scintigraphy demonstrated increased uptake in the left proximal femur. Hip disarticulation was performed. The removed tumor was composed of highly anaplastic cells. Lace-like irregular osteoid formation was observed among the tumor cells. MPNST component was totally absent. The tumor was diagnosed as osteoblastic type osteosarcoma. Two months after disarticulation the patient died of bilateral pulmonary metastasis. The correlation between the histogenesis of osteosarcoma and the genetic abnormality in NF1 patients has not been elucidated, but the finding of osteosarcomatous transformation in this case suggests the divergent cellular differentiation to mesenchymal malignant tumors of neuroectodermal tissue in NF1 patients.

Extraskeletal osteosarcoma located to the gallbladder

Extraskeletal osteosarcoma is a rare malignant soft tissue tumour. At open cholecystectomy performed for gallstones, a 61-year-old woman was found to have osseous tissue in the wall of the gallbladder. Histopathological examination of the specimen revealed a focus of extraskeletal osteosarcoma. The patient developed widespread intra-abdominal metastases 5 months after the operation, and died of pulmonary deposits at 9 months. Although osteosarcoma has rarely been reported at other extraskeletal sites, this appears to be the first case of a primary tumour in the gallbladder.