Light micrograph section through human soft connective tissue showing sarcomatoid carcinoma. Sarcoma is a type of cancer can occur in various locations in the body. It refers to a broad group of cancers that begin in the bones and in the soft connective tissues. Sarcomatoid carcinoma is a rare aggressive, malignant cancer composed of sarcoma and sarcoma-like components and can occur in different organs, such as the thyroid gland, bone, breast, pancreas, liver, urinary tract and lungs.