Endobronchial metastasis as an uncommon pattern of metastatic dissemination from small cell osteosarcoma

Endobronchial metastasis (EBM) from extrapulmonary primary malignancy is a rare entity. Although the most common site of metastasis of osteosarcoma is the lungs, EBM remains a rare occurrence. Cough and dyspnea are the most common symptoms. A significant number of patients are asymptomatic, making the diagnosis without any radiographic imaging challenging. CT scan of the lung, along with bronchoscopy and biopsy, is the mainstay of diagnosis and staging. A 36-year-old man presented with small cell osteosarcoma of the left maxillary region and was treated with surgery and adjuvant chemotherapy. The patient presented 8 years later with axillary metastasis and was found to have lung metastasis on further workup. Bronchoscopy and biopsy proved an EBM that was debulked by hot snare technique. The patient was then started on chemotherapy for recurrent small cell osteosarcoma.

Establishment and Characterization of a Human Small Cell Osteosarcoma Cancer Stem Cell Line: A New PossibleIn VitroModel for Discovering Small Cell Osteosarcoma Biology

Osteosarcoma (OSA) is the most common primary malignant bone tumor, usually arising in the long bones of children and young adults. There are different subtypes of OSA, among which we find the conventional OS (also called medullary or central osteosarcoma) which has a high grade of malignancy and an incidence of 80%. There are different subtypes of high grade OS like chondroblastic, fibroblastic, osteoblastic, telangiectatic, and the small cell osteosarcoma (SCO). In this study, for the first time, we have isolated, established, and characterized a cell line of cancer stem cells (CSCs) from a human SCO. First of all, we have established a primary finite cell line of SCO, from which we have isolated the CSCs by the sphere formation assay. We have proved theirin vitromesenchymal and embryonic stem phenotype. Additionally, we have showed their neoplastic phenotype, since the original tumor bulk is a high grade osteosarcoma. This research demonstrates the existence of CSCs also in human primary SCO and highlights the establishment of this particular stabilized cancer stem cell line. This will represent a first step into the study of the biology of these cells to discover new molecular targets molecules for new incisive therapeutic strategies against this highly aggressive OSA.