Pseudotumor of the head and neck masquerading as neoplasia.

Four unusual cases of pseudotumor, which had clinical and radiographic findings suggesting neoplasia, are presented. One involved the maxillary sinus, destroying the lateral wall, and extending to the infratemporal fossa and the orbit. The second presented as an enlarging lacrimal gland tumor with ipsilateral parotid adenopathy, and the third as a large parapharyngeal mass that was diagnosed as a lymphoma on aspiration cytology. The fourth case documented the rare occurrence of a congenital pseudotumor, manifesting as proptosis in a neonate and thought to be a fibrosarcoma on frozen section study. Aggressive pseudotumors must be distinguished from malignancy to avoid unnecessary surgery or irradiation. Some cases can be distinguished from neoplasms by their dramatic response to oral steroid therapy, and others by characteristic features on CT or MRI. Due to the diverse cellular proliferation, aspiration cytology is infrequently helpful and diagnosis can be difficult on frozen section study. An approach to the diagnosis and management of pseudotumors is detailed.