"Parapharyngeal space" tumors: a cytopathological study of 24 cases on fine-needle aspiration

The parapharyngeal space (PPS) is a well-defined anatomic zone of loose connective tissue lying deep to the tonsil and lateral to the pharynx. Neoplasms arising within the PPS are rare. We retrospectively reviewed 24 PPS fine-needle aspirations (FNAs) performed at The Johns Hopkins Hospital over the past 16 years (1987-2002). Patients presented with neck pain, dysphagia, and/or intraoral swelling of varying duration. Radiographic imaging disclosed PPS masses, varying in size from 2.5 to 8 cm. The most common clinicoradiographic suspicion was a nerve sheath tumor. Six cases had FNA performed using a 23-gauge needle via a transoral approach in the outpatient suite whereas the remainder were aspirated via a 22-gauge Franseen needle under CT guidance. Six of 24 cases (25%) were nondiagnostic due to lack of adequate cellular material. Of the 18 cases considered diagnostic, there were nine (50%) pleomorphic adenomas (PAs); three (17%) squamous-cell carcinomas (SCC); and one each of oncocytoma, adenocarcinoma, not otherwise specified (NOS), adenoid cystic carcinoma, lipoma, neurofibroma, and non-Hodgkin lymphoma, together comprising the remaining 33%. Four of the six cases deemed nondiagnostic (consisting predominantly of blood) on subsequent tissue follow-up revealed paraganglioma (two cases), SCC (one case), and schwannoma (one case). PPS is an uncommon target of an FNA procedure. PPS masses represent a heterogeneous group of neoplasms of which PA appears most common, representing 50% of our diagnostic cases. The rate of nondiagnostic FNA samples is moderately high due to excessive bleeding encountered in this location and other technical problems relating to adequately targeting the lesion in close vicinity of major neck vessels.