Under local anesthesia, a small biopsy was taken. The results of the incisional biopsy were such that further treatment was deemed unnecessary.

Incisional Biopsy

Histologic examination of the H & E section revealed a trisected small piece of mucosa covered by epithelium and supported by dense fibrous connective tissue (Figure 2). The connective tissue contained small clusters of a dark-brown granular material, some of which was golden brown and finely granular which stained positively for melanin stain Masson Fontana (Figure 3). There were other small clusters of brown pigment that was larger and more variable in size dark brown granules that stained blue with iron stain (Figure 4). Figure 4 shows a combination of dark blue pigment consistent with hemosiderin and small granular golden-brown pigment consistent with melanin. Immunohistochemistry stain was negative with S-100 antibody..

Figure 2 Low power (x100) histology shows H & E stained section with surface epithelium and underlying dense fibrous connective tissue containing small clusters of brownish granular material.

Figure 3 Higher power (x200) histology shows Masson-Fontana, special stain for melanin demonstrating small clusters of brown pigment staining positively with Masson Fontana. The pigment is golden brown and finely granular.

Figure 4 Higher power (x200) histology shows iron stain for hemosiderin pigment. Note the clusters of blue pigment staining positively with iron stain confirming that some of the brown pigment was hemosiderin.