Chapter 8

Oropharynx and Tonsils

Cytology is a useful, rapid screening test for lesions in the oropharynx, including masses, ulcers, draining tracts, plaques, and enlarged tonsils. It can be performed alone or in conjunction with biopsy, and/or sampling for bacterial and fungal testing. Sedation or anesthesia can be necessary for complete examination of the oropharynx and to obtain adequate, representative samples. For mass lesions and plaques, aspiration of the deeper layers of the lesion to avoid any superficial secondary inflammation is usually most rewarding. If a mass lesion is nonexfoliative, scraping the lesion may yield adequate numbers of cells; however, excisional biopsy is usually necessary for a definitive diagnosis and prognosis. For flat lesions, including ulcers, biopsy of the entire lesion, or at least of the edge of a lesion to evaluate early, primary abnormalities, is usually necessary to obtain an adequate number of representative cells for evaluation. However, impression smears or scrapings of ulcerative lesions can often yield cells or organisms that are distinctive and can be identified as the primary cause of the lesion, rather than as secondary opportunists, and eliminate the need for biopsy. Because the oropharynx and tonsils are highly vascular, care must be taken to avoid hemodilution of the sample at the time of collection.

Techniques

For mass lesions and plaques, fine-needle aspiration should be attempted after the surface has been cleaned with a disinfectant that is nontoxic to the digestive system of the patient. If the lesion is fibrous and nonexfoliative, scraping the lesion with a scalpel blade and transferring the cells to a slide can be rewarding if the cells are immediately thinned into a monolayer by smearing them with another slide or by using a saline-moistened sterile swab to roll (not rub) the cells along a slide. Draining tracts can also be swabbed and the cells rolled onto a slide for cytologic examination. If a biopsy is performed, impression smears of the cut surface can be made after the surface has been blotted on a paper towel to remove excessive blood and tissue fluids. For flat lesions such as ulcers, any superficial pus and fibrin should be removed before impression smears or scrapings of the surface are made. As for all cytology samples, the smears should be thin enough to dry within 30 to 60 seconds, and they should be completely dry before encasing them in a slide holder for transport to a diagnostic laboratory. Areas of the sample that are more than one cell thick cannot be adequately evaluated, and slow drying causes distortion and disintegration, which could ruin otherwise excellent smears.

Normal Findings

To correctly identify abnormal criteria, recognition of normal findings is essential. The oropharynx and tonsils are covered by mature squamous epithelial cells (Figure 8-1). These are large, flat, and round to slightly angular. They have abundant pale cytoplasm and small round nuclei that exhibit condensed chromatin. Nucleoli are not visible, and some cells are anuclear. The presence of occasional intermediate squamous cells with slightly larger, less condensed nuclei is normal (Figure 8-2).

Figure 8-1 Mature squamous cells have cornified cytoplasm that has sharp angular borders. Mature squamous cells may be nucleated or anucleate. A, Mature nucleated squamous cells have abundant light blue-gray cytoplasm that has an angular appearance. B, Mature squamous cell with a pyknotic nucleus (lower left) and anucleate, mature squamous cells from a scraping of oral tissue.

Figure 8-2 Intermediate (less differentiated) squamous cells.
These are also a normal finding from the oropharynx, particularly with samples collected by scraping. Cells are more cohesive and have large, noncondensed nuclei and a more deeply basophilic cytoplasm that does not have angular borders.

The normal squamous cells frequently exhibit a mixed bacterial population adhered to their surfaces (Figure 8-3). These bacteria are also usually present in the background between cells. The normal flora includes aerobic and anaerobic bacterial rods and cocci. Observation of spirochetes is considered normal. Yeast organisms are never considered normal. One bacterium, Simonsiella spp., has a characteristic palisading appearance and is a normal inhabitant of the oropharynx (Figure 8-4). It should never be mistaken for a pathogen. If the bacterial population is dominated by only one type of bacteria, that would be considered abnormal.