Under local anesthesia, the larger pedunculated lesions, especially those that tended to become trapped between teeth, were excised and submitted for microscopic examination. The other lesions received weekly injections with three million units of alpha interferone B.

Excisional Biopsy

Histologic examination reveals multiple pieces of soft tissue composed of papillary surface epithelium (Figure 3) with an underlying fibrous connective tissue core. The latter was loose and vascular and was focally infiltrated by lymphocytes. The papillary projections ranged from blunt to elongated and were all covered by parakeratin of variable thickness. The keratin layer of some of the specimens was infiltrated by fungal hyphae and spores. The spinous layer showed evidence of cells with empty-looking cytoplasm and small nuclei consistent with koilocytes (Figure 4). The immunohistochemistry stain with antibody to human papilloma virus types 6/11, 16, etc (Figure 5) was strongly positive.

Figure 3 Low power (x40) H & E histology shows papillary epithelium covered by parakeratin and supported by fibrous connective tissue core.

Figure 4 Low power (x100) H & E histology demonstrating spinous layer cells with mitosoid cells and koilocytes.

Figure 5 Low power (x100) Immunohistochemistry stain with antibody to HPV types 6/11, 16, demonstrating strong positive nuclear staining at the superficial spinous layer.