Cloud-like patt ern of mineralization in skull base osteosarcoma

Abstract

A 40-year-old woman, a known case of le ft temporal bone osteosarcoma operated 3 years back, now presented with progressively increasing swelling over the previously operated site for the previous 6 months and foul smelling discharge for 3 days. Not able to take food, breathing diffi culty, and was in altered sensorium. At the time of initial presentation (3 years back) there was pinkish, fi rm to hard, moderately vascular, nonsuckable tumor, in fi ltrating into the temporal muscle and fascia with ill-defi ned plane of cleavage. The tumor was adherent to the dura but there was no dural invasion. Histologically the tumor comprised highly pleomorphic tumor cells, fi ndings suggestive of anaplastic variant of osteosarcoma and a poor prognosis was predicted. The patient received a course of chemotherapy but did not receive radiotherapy. Plain axial CT images of the head so ft tissue and bone showed an aggressive, densely ossifi ed bone-forming tumor with extensive involvement of the soft tissue and bony destruction of the anterior, middle, and part of the posterior cranial fossa on le ft side [Figure 1]. The patient was managed conservatively but did not do well and expired aft er 3 days of admission.Fibro-osseous lesions are characteristically centered within bone and surface fi bro-osseous lesions prompt consideration of parosteal osteosarcoma, which is rare but well documented in the skull.