Teaching Case

An eighty years old woman presented to our hospital complaining of painful swelling of the right inguinal area (firstly noted by the patient one month ago).

An eighty years old woman presented to our hospital complaining of painful swelling of the right inguinal area (firstly noted by the patient one month ago). On examination a palpable mass was discovered at the right inguinal area. The conventional x-ray radiograph of the pelvis showed a lytic lesion of the right pubic bone. Ultrasonography showed a mixed echogenity mass. A computed tomography scan with contrast enhancement followed. It showed an expanded erosive lesion with flecks of calcification. Liver, pancreas, spleen, kidneys were normal. The CXR was normal. Retroperitoneal lymph nodes were not found. Laboratory tests showed CA15-3 marker value: 31,2 u/ml (normal 0-28), alkaline phosphatase 157 u/l (normal 30-125). An ultrasound-guided biopsy with 14 gauge cutting needle was performed to establish the final diagnosis.

Osteosarcoma is the commonest primary malignant tumour. Typically it appears in adolescent or young adults (10-25 years) slightly predominant in males. It presents usually with localized pain or swelling around the knee. Osteosarcomas are infrequently found in the pelvis and spine. Histologically it is pleomorphic. Two diagnostic features exist: a production of osteoid tissue and presence of alkaline phosphatase within the tumour cells. If cells of cartilage origin are present calcification may be a presenting feature. CT gave us useful information concerning the calcification and the extension of the mass. Biopsy with a cutting needle was performed easily and quickly, as the mass was not very hard. US was useful for avoiding the large inguinal vessels. Our primary diagnosis in this case was chondrosarcoma. Osteosarcoma occurs in older age groups of patients usually associated with Paget’s disease or radiation therapy following treatment of another cancer. In our case there were no signs or history of Paget’s disease, fibrous dysplasia, radiation therapy or existence of osteoblastoma. Furthermore low grade osteosarcoma and parosteal osteosarcoma occur in an older patient population than conventional osteosarcoma.