Alveolar soft part sarcoma: the new primary intracranial malignancy

The purpose of this paper is to serve as a reference to aid in the management of this poorly understood intracranial malignancy. The authors report their experience treating the eighth ostensible case of a primary intracranial alveolar soft part sarcoma (ASPS). A 21-year-old man presented to hospital after collapsing. He gave a 1-year history of headache, a 2-month history of reduced visual acuity and on examination had left facial paraesthesia with left-sided incoordination. MRI of the brain revealed a large left posterior fossa mass. The patient underwent resection of the tumour with good recovery in function. Immunohistochemical analysis of the tumour specimen confirmed an ASPS, and multimodal imaging in search of an extra-cranial disease primary was negative. A review of the literature yielded only seven other cases of primary intracranial ASPS. A variety of diagnostic imaging modalities were employed in search of a disease primary, as were various combinations of surgical resection, chemotherapy and radiotherapy as treatment. Half of the cases documented delayed disease recurrence. The authors discuss the following: the unique radiological and immunohistological characteristics of this disease including the potential for its misdiagnosis; the investigations required to diagnose a primary intracranial ASPS; the efficacy of current medical and surgical treatment options and the factors that will aid in prognostication. This is the first review of this new primary intracranial malignancy. From our analysis, we offer a joint radiological and immunohistochemical algorithm for the diagnosis of primary intracranial ASPS and specific operative considerations prior to resection.