Gnathic and peripheral ameloblastomas lack human papillomavirus DNA.

Human papillomavirus (HPV) has been associated with a variety of head and neck neoplasms, including squamous cell carcinomas and Schneiderian papillomas. Ameloblastomas can arise from either the gnathic bones or peripheral soft tissues. Peripheral sinonasal ameloblastomas share clinical features with Schneiderian papillomas. A small number of reports have described detection of HPV DNA within ameloblastomas. However, Most of these cases was reported in the 1990s, used the polymerase chain reaction technique, and only examined gnathic tumors. The current study was designed to determine whether low- or high-risk HPV DNA could be detected in gnathic or peripheral ameloblastomas using in situ hybridization. Twenty-nine examples of gnathic osseous and peripheral head and neck ameloblastomas were obtained from the authors' archives (University of Virginia and the Johns Hopkins Hospital). High-risk HPV DNA was not detected in any of the 29 tumors analyzed. Low-risk HPV DNA was identified in only 1 tumor, which was peripheral in origin, and from an immunocompromised patient. We believe that the HPV in this case represents a background "passenger" infection. This study demonstrates that HPV of either high- or low-risk subtypes is unlikely to play a role in the pathogenesis of sinonasal ameloblastomas.

Basal cell carcinoma vs basaloid squamous cell carcinoma of the skin: an immunohistochemical reappraisal.

Typical cutaneous basal cell carcinoma (BCC) and squamous cell carcinoma (SCC) are morphologically dissimilar. It is well known, however, that poorly differentiated SCC may assume a basaloid phenotype, complicating the histologic distinction between these 2 neoplasms. Selected immunohistochemical stains have been used in the past to aid in that differential diagnosis. In the current study, additional markers were evaluated to determine whether they would be helpful in that regard. Twenty-nine cases of metatypical (squamoid) BCC (MBCC) and 25 examples of basaloid SCC (BSCC) were studied using the antibodies Ber-EP4 and MOC-31 as well as a plant lectin preparation from Ulex europaeus I (UEA-1). The resulting immunostains were interpreted independently by 3 pathologists, and the results showed that MBCCs demonstrated strong and diffuse staining for Ber-EP4 (25/29) and MOC-31 (29/29). In contrast, BSCCs tended to be only sporadically reactive for both markers (4/25 and 1/25 cases, respectively). Labeling for UEA-1 was observed in almost all BSCCs (24/25), but only 6 of 29 cases of MBCC showed limited, focal staining with that lectin. These data suggest that MOC-31 is a useful marker in the specified differential diagnosis, especially when used together with UEA-1.

The Utility of GATA3 in the Diagnosis of Urothelial Carcinomas With Variant Morphologic Patterns.

The transcription factor GATA3 is a recently described biomarker that is highly expressed in bladder and breast carcinomas. Although it has shown sensitivity as a marker of primary bladder carcinomas with purely urothelial differentiation, the ability of GATA3 to label primary bladder carcinomas with variant morphologic patterns has been incompletely assessed to date. The current study was designed to determine whether GATA3 staining is retained in "unconventional" bladder carcinomas. Eighty-eight cases of primary bladder cancers were retrieved from the authors' institutional archive, and they included the following histomorphologic types: 6 small cell carcinomas, 12 sarcomatoid carcinomas, 17 adenocarcinomas (both primary and urothelial variants with glandular differentiation), 24 micropapillary carcinomas, and 27 squamous cell carcinomas (both primary and urothelial variants with squamous differentiation). A tissue microarray was constructed and automated immunostaining for GATA3 (Clone L50-823, Biocare Medical, Concord, CA) was performed using standard technique. Among the 5 variants of unconventional bladder carcinoma, only the micropapillary and sarcomatoid forms exhibited consistent and strong immunolabeling for GATA3. Hence, the sensitivity of this determinant is diminished in several histologic forms of primary bladder carcinoma. That fact will affect the interpretation of GATA3 stains in the context of possible metastasis from primary bladder carcinomas with variant morphologic patterns, as well as their distinction from secondary bladder involvement by tumors of nonurothelial origin.