Examination of the skin biopsy specimen revealed numerous submucosal melanophages, without inflammation within the fungiform papillae, consistent with a diagnosis of pigmented fungiform papillae of the tongue. The pigment within the melanophages was positive for melanin on Fontana-Masson staining but was negative for iron on Prussian blue staining.
The surface of the tongue contains 3 types of papillae: filiform, fungiform, and circumvallate. Filiform papillae, which are the most numerous, appear as short, hairlike projections that are evenly distributed on the dorsum of the tongue. Fungiform papillae are larger, flatter, and concentrated mainly on the anterior and lateral aspects. Circumvallate papillae, which are the largest but least numerous type of papillae, are found toward the posterior of the tongue.1
Hyperpigmented Patches on the Tongue of a Young Girl—Diagnosis. Arch Dermatol. 2004;140(10):1275-1280. doi:10.1001/archderm.140.10.1275-h