Basaloid squamous cell carcinoma of the maxilla: Report of a case and literature review

Constitutive Hedgehog/GLI2 signaling drives extracutaneous basaloid squamous cell carcinoma development and bone remodeling

Uncontrolled activation of the Hedgehog (Hh) signaling pathway, operating through GLI transcription factors, plays a central role in the pathogenesis of cutaneous basal cell carcinoma and contributes to the development of several malignancies arising in extracutaneous sites. We now report that K5-tTA;tetO-Gli2 bitransgenic mice develop distinctive epithelial tumors within their jaws. These tumors consist of large masses of highly proliferative, monomorphous, basaloid cells with scattered foci of keratinization and central necrosis, mimicking human basaloid squamous cell carcinoma (BSCC), an aggressive upper aerodigestive tract tumor. Like human BSCC, these tumors express epidermal basal keratins, and differentiation-specific keratins within squamous foci. Mouse BSCCs express high levels of Gli2 and Hh target genes, including Gli1 and Ptch1, which we show are also upregulated in a subset of human BSCCs. Mouse BSCCs appear to arise from distinct epithelial sites, including the gingival junctional epithelium and epithelial rests of Malassez, a proposed stem cell compartment. Although Gli2 transgene expression is restricted to epithelial cells, we also detect striking alterations in bone adjacent to BSCCs, with activated osteoblasts, osteoclasts, and osteal macrophages, indicative of active bone remodeling. Gli2 transgene inactivation resulted in rapid BSCC regression and reversal of the bone remodeling phenotype. This first-reported mouse model of BSCC supports the concept that uncontrolled Hh signaling plays a central role in the pathogenesis of a subset of human BSCCs, points to Hh/GLI2 signaling as a potential therapeutic target, and provides a powerful new tool for probing the mechanistic underpinnings of tumor-associated bone remodeling.

The importance of adjuvant treatment and primary anatomical site in head and neck basaloid squamous cell carcinoma survival: an analysis of the National Cancer Database

PURPOSE

Basaloid squamous cell carcinoma (BSCC) of the head and neck is an aggressive and highly malignant variant of squamous cell carcinoma that accounts for 2% of head and neck cancers. Previous studies have not analyzed the significance of adjuvant chemoradiation and anatomical site within BSCC subtype and its impact on survival.

METHODS

A cohort of 1999 patients with BSCC of the head and neck was formed from the National Cancer Database and analyzed with descriptive studies, median survival and 5- and 10-year survival. A multivariable Cox hazard regression was performed to determine the prognostic significance of anatomical site and adjuvant therapy.

RESULTS

The most common primary anatomical site was the oropharynx (71.9%) followed by oral cavity (11.5%), larynx (10.1%), hypopharynx (3.5%), esophagus (1.9%), and nasopharynx (1.1%). The presence of metastasis increased the risk of mortality (HR = 2.14; 95% CI 1.40-3.26). Tumors localized to the oropharynx demonstrated better survival compared to all sites except nasopharynx, including the oral cavity (HR = 2.45; 95% CI 1.83-3.29), hypopharynx (HR = 2.58; 95% CI:1.64-4.05), and larynx (HR = 2.89; 95% CI:2.25-3.73). Adjuvant chemoradiation (HR = 0.36; 95% CI 0.23-0.58) and adjuvant radiation (HR = 0.38; 95% CI 0.23-0.64) had better survival outcomes compared to adjuvant chemotherapy. Patients with microscopic margins had better survival outcomes when compared to no surgery (HR = 0.38, 98% Cl 0.23-0.64) while there were no better survival outcomes of patients with macroscopic margins compared to no surgery.

CONCLUSION

This study illustrated that tumors in the oropharynx, lower age, adjuvant chemoradiation and radiation, and microscopic margins were associated with greater survival.

Cause-specific mortality prediction model for patients with basaloid squamous cell carcinomas of the head and neck: a competing risk analysis

Purpose: Basaloid squamous cell carcinoma (BSCC) is a rare, high-grade variant of squamous cell carcinoma (SCC). Most published studies based on population-based datasets focus on prognostic differences between SCC and BSCC. Competing risk analyses for this disease have not been performed. We used Surveillance Epidemiology and End Results (SEER) data to calculate and model the cumulative incidence of death for patients with head and neck BSCC (HNBSCC) with competing risk approaches, and built a model to predict probability of cause-specific death for these patients.

Methods: We analyzed data on 1163 patients who were diagnosed with primary lip and oral cavity, oropharynx, or hypopharynx and larynx BSCC and registered in the SEER program between 2004 and 2013. We calculated crude cumulative incidence function (CIF) for mortality after diagnosis of HNBSCC. We built a Fine and Gray's proportional sub-distribution hazard model and nomogram to predict their probability of cause-specific death. We calculated concordance indexes (c-index) and plotted calibration curves to evaluate model performance.

Results: Five-year cumulative incidence of cause-specific death after diagnosis of HNBSCC was 26.5% (95% CI: 23.4-29.8%); cumulative incidence of other causes of death was 11.8% (95% CI: 9.4-14.3%). Old age, large tumor size, hypopharynx and larynx sites, lymph node-positive, distant metastasis, and non-radiotherapy were significant factors for high probability of cause-specific death. The model was well calibrated. The bootstrap-corrected c-index for the model was 0.71.

Conclusions: We built the first competing risk nomogram for HNBSCC. The model performance was found to be good. This individualized prognostic predictive tool will aid physicians in clinical counseling, and will assist patients in planning for their future lives.

Basaloid Squamous Cell Carcinoma of Tongue: A Report with Emphasis on Immunohistochemistry

Basaloid Squamous Cell Carcinoma (BSCC) is a rare entity with its histopathological distinction from conventional squamous cell carcinoma. It is frequently considered a high-grade carcinoma with poor prognosis because of higher rate of distant metastases. Here by, we are reporting a case of 39-year-old male with an ulcer on the left lateral border of the tongue since a month. Histopathological examination of incisional biopsy revealed basaloid tumour cell islands accompanied by component of well differentiated squamous cell carcinoma. To reconfirm this incidental finding immunohistochemistry was carried out for Proliferative Cell Nuclear Antigen (PCNA) and pancytokeratin (AE1/AE3) which was positive to conclude diagnosis of BSCC. Further p16 staining was done to rule out Human Papilloma Virus (HPV) infection.