CLINICOPATHOLOGIC REVIEW:
Papillary Lesions of the Oral Cavity
SAP presents in older adults, with a slight male predominance
(female-to-male ratio of 1.37-1.5: 1.0).2, 11 It clinically manifests as
a slow-growing, papillary, exophytic growth that resembles SP.
Histologically, SAP displays some similarities to SP at low-power.
It demonstrates numerous papillary, exophytic, stratified squamous
epithelial projections. However, SAP is differentiated from SP by
its biphasic growth pattern, with an exophytic component and
an endophytic component.11 Upon examination at higher power,
the epithelium of SAP is continuous with a proliferation of ductal
epithelium present within the deeper connective tissue.2 The
ductal component is lined by a double layer of cells (a tall,
columnar, luminal layer and a smaller, cuboidal, basalar layer)
which project into the connective tissue, forming multiple lumina
or duct-like spaces. A proliferation of small and ectatic ducts is
seen in the connective tissue.11 The ductal cells may be oncocytic
in appearance, and there is usually a mixed inflammatory infiltrate
of plasma cells, neutrophils, and lymphocytes in the connective
tissue. Occasionally, a squamous papilloma may arise in close
proximity to a minor salivary gland duct, and mucous cells may
be scattered in the epithelium of the lesion. However, SP should
not be confused with SAP, as SP arises from surface epithelium
and not minor salivary tissue and otherwise lacks characteristic
features of SAP. The treatment of choice is conservative surgical
excision, and recurrence of the lesion is rare. Since SAP has a
papillary appearance, it could be considered in the differential
diagnosis for this case. While the palate is the most common site
for SAP, the lesion could develop on other oral tissues, including
the buccal commissure. However, SAP is a rare entity, and this
alone would place this lesion lower on the list of possibilities.
CONCLUSION
Since clinical features overlap, papillary lesions may be difficult to
differentiate from one another purely based on clinical appearance.
Some features, such as location of the lesion, size, keratinization,
whether the lesion is solitary or occurs in a cluster, and patient
demographics may also be helpful in establishing a useful
diagnosis. Given that SP is by far the most common papillary
lesion seen intraorally, accounting for 3 percent of all submitted
biopsy specimen, it is typically the favored diagnosis for a solitary
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papillary lesion developing on oral mucosal tissues. However, a
biopsy is generally necessary to confirm the diagnosis. The
recommended diagnostic and therapeutic approach for oral
papillary lesions is excisional biopsy. While SP, VV, and CA are
induced by genotypes of HPV, VX and SAP are unrelated to the
virus. HPV-related lesions are potentially transmittable and should
be removed. Simple excision is also the recommended treatment
approach for VX and SAP. Occasionally, a small verrucous carcinoma
could mimic a benign papillary lesion. Since the patient described
above was lost to follow-up, and an excisional biopsy was not
performed, a definitive diagnosis could not be established in this
case. However, a proper differential diagnosis can be formulated
given the clinical presentation, and includes the lesions discussed
in this article. Based on statistics and the clinical features of the
present lesion, SP should be the favored diagnosis.
REFERENCES
1. Carneiro TE, Marinho SA, Verli FD, et al. Oral squamous papilloma: clinical,