Hydatid disease is caused by the parasitic tapeworm Echinococcus. This parasite in larval stage can thrive in many parts of the body, most commonly in the liver and the lung. Hydatid disease in the head and neck region is rare. An unusual location for hydatid disease in the pterygopalatine fossa-infratemporal fossa is presented. The patient did not have evidence of any other cyst on a ten-year follow-up.

Solitary fibrous tumour was first described as a pleural tumour. It has been reported in a number of extrapleural sites including the head and neck. We present the first case of solitary fibrous tumour of the infratemporal fossa described in the English literature. Complete excision was achieved using the orbitozygomatic infratemporal craniotomy approach.

Solitary fibrous tumors are uncommon spindle cell neoplasms generally associated with serosal surfaces, especially the pleura. Recently, these tumors have been documented in a number of extrapleural sites including the head and neck. So far only two cases of parapharyngeal solitary fibrous tumor have been reported in the English literature. Rare location of an uncommon lesion often gives rise to difficulty in diagnosis or to misdiagnosis. In both the previously reported cases, as well as in our case, the diagnosis of solitary fibrous tumor was not made until the excised tumor was subjected to histopathology and immunohistochemistry.

Cellula r schwannomas are a benign variant of classic schwannomas. Their histologic appearance closely mimics that of malignant periph eral nerve-sheath tumors, which are high-grade sarcomas. In this article, we describe what to our knowledge is the fi rst reported case of a cellular schwannoma ofthe paranasal sinuses and only the 33'dreported case of any schwannoma at this site. We also discuss the histology and management of cellular schwannomas and review the pertinent literature.

Endodermal sinus tumor is an uncommon malignant germ cell tumor that occ urs in both gonadal and extragonadal tissues. Endodernial sinus tumors of the head and neck, exclusive of the central nervous system, are rare. We report a case of endoden nal sinus tumor arising fro m the maxillary sinus in a 4-year-old boy. Combined treatment with radiation therapy and chemotherapy resulted in complete tumor regression.