Letter to the editor: osteogenic sarcoma--cutaneous metastases

Cutaneous and subcutaneous metastasis of appendicular osteosarcoma in dogs: 20 cases

Background

Metastasis of appendicular osteosarcoma is most common to the lungs and is generally considered a terminal event in dogs. Behavior and prognosis associated with cutaneous or subcutaneous metastases (CSM) is poorly defined.

Objective

Describe the population and gather prognostic information regarding appendicular osteosarcoma with CSM in dogs.

Animals

Twenty dogs with appendicular osteosarcoma and CSM.

Methods

Retrospective case series. Medical records were searched to identify dogs diagnosed with appendicular osteosarcoma that developed CSM. Demographic data, order of metastatic events, and CSM clinical features were evaluated. Kaplan‐Meier survival curves were constructed and log‐rank tests were used to compare survival between groups of dogs.

Results

In 19 dogs (95%), CSM was an incidental finding. Seventeen dogs (85%) developed pulmonary metastasis, and 1 dog (5%) developed bone metastasis. No other metastatic sites were detected before euthanasia. The median CSM‐free interval and CSM survival time were 160 days (range: 0‐542 days) and 55 days (range: 5‐336 days), respectively. The median CSM survival time was significantly longer for dogs treated with surgery and chemotherapy (94 days) or chemotherapy only (64 days) than for dogs that did not receive these treatments (11 days) (P = .002 and P = .03, respectively). No other factors were associated with survival after diagnosis of CSM.

Conclusion and Clinical Importance

The skin or subcutaneous tissue can be the first osteosarcoma metastatic site detected. After CSM diagnosis, the prognosis is grave with median survival <2 months. Although this finding could have been biased by case selection, treatment with surgery and chemotherapy may improve outcome.

Cutaneous extraskeletal osteosarcoma on the scar of a previous bone graft

Extraskeletal osteosarcoma (ESOS) is a very rare malignant tumor of mesenchymal origin. It is rarer than osseous osteosarcoma and there are very few reports of the skin being a primary site. Most reported cutaneous ESOS were accompanied with metastasis in other organs. A 56-year-old man presented with a painful, 1.5×0.8 cm sized, brown-colored nodule on the right girdle area for 3 months. The histologic findings revealed a tumor that was confined to the dermis without connection to the subcutaneous tissue. In addition, there were large amounts of thin and lace-like bony trabeculae and osteoid with neoplastic cells in a highly pleomorphic sarcomatous stroma.

Isolated subcutaneous metastasis of osteosarcoma 5 years after initial diagnosis

The pediatric malignancies most likely to metastasize to the skin are neuroblastoma, leukemia, and rhabdomyosarcoma. Cutaneous and subcutaneous metastases from osteosarcoma are extremely rare, with only a few cases reported in pediatric patients with multifocal synchronous osteosarcoma. We describe the case of a 19-year-old woman with a single subcutaneous nodule of the abdominal wall that, on histologic evaluation, proved to be a metastatic high-grade osteosarcoma 5 years after her initial diagnosis.

Osteosarcoma of the skin

BACKGROUND

Osteosarcoma is a common malignancy, although skin metastasis is rare. We sought to review the incidence, epidemiology, risk factors, and prognosis of osteosarcoma with skin involvement.

METHODS

We conducted a retrospective chart review that covered 30 years and involved clinic patients younger than 18 years who had cutaneous metastases of osteosarcoma. The main outcome measure was histologic documentation of both primary tumor and metastatic lesion in the skin.

RESULTS

Two patients were found to have osteosarcoma with skin involvement. No unifying factors were identified.

CONCLUSIONS

Although osteosarcoma is a common malignancy with frequent metastases, involvement of the skin is rare. Further studies to identify risk factors and subsequent prognosis are necessary. Nevertheless, unidentifiable skin lesions in a patient with a history of osteosarcoma should be investigated to rule out tumor metastasis, regardless of cancer status.

Extraskeletal cutaneous chondroblastic osteosarcoma: a case report

Extraskeletal osteosarcoma is an uncommon neoplasm that usually arises in the deep soft tissues, especially in the lower extremities, with rare cases involving the subcutis or dermis. We report a 60-year-old man with an enlarging cutaneous mass in the right lower thigh. An incisional skin biopsy showed a well-defined, but non-encapsulated neoplasm, characterized by extensive cartilage with marked cellularity, atypia and high mitotic activity, involving the dermis and subcutis. Although osteoid or bone was not observed, a diagnosis of cutaneous chondroblastic osteosarcoma was suggested after excluding an origin in bone or other primary tumor sites by imaging techniques. Histopathologic features of the surgical specimen were characteristic, with a predominant high-grade chondroid component together with focal fibrosarcomatous zones, areas of multinucleated giant cells and foci of bone and osteoid formation. The patient underwent postoperative chemotherapy and is currently alive with pulmonary metastases 15 months after surgery. In summary, we report a unique case of cutaneous osteosarcoma of the chondroblastic subtype, diagnosed on incisional skin biopsy despite the absence of osteoid or bone during tumor sampling. As a rule, when an obviously malignant 'chondrosarcoma' is identified, one should always consider this entity.

Primary cutaneous extraskeletal osteosarcoma under a previous electrodessicated actinic keratosis

Extraskeletal osteosarcoma represents approximately 1% of soft tissue sarcomas and approximately 4% of all osteosarcomas. It is therefore much rarer than osteosarcoma arising primarily in bone. Skin as a primary site has seldom been reported. This report describes an extraskeletal osteosarcoma of the skin under a previously electrodessicated actinic keratosis.