Which tumor is associated with malignant round-cell tumors?

Ewing's sarcoma is indeed associated with malignant round-cell tumors. This type of tumor is primarily found in children and young adults and is characterized by small, round cells that can be seen histologically. Ewing’s sarcoma arises from the bone or soft tissue and is categorized as a primitive neuroectodermal tumor (PNET), which consists of small blue cells that share similarities in appearance with other malignant round-cell tumors.

The presence of these small, round cells is a hallmark of Ewing's sarcoma and has diagnostic significance. The tumor is often located in the long bones or the pelvis and can present with pain, swelling, and systemic symptoms like fever. Its aggressive nature and tendency to metastasize highlight the importance of early diagnosis and treatment.

Other tumors mentioned, such as osteosarcoma, rhabdomyosarcoma, and neuroblastoma, have distinct histopathological features that differ from those seen in Ewing's sarcoma. Osteosarcoma typically consists of pleomorphic spindle cells and osteoid formation, while rhabdomyosarcoma has a more varied cellular appearance depending on the subtype (embryonal or alveolar). Neuroblastoma is characterized by neuroblasts and has a unique histological