Human papillomavirus-related multiphenotypic sinonasal carcinoma: A report of two patients and review of the literature

Surgical treatment for uncommon malignancies of the paranasal sinuses and anterior cranial fossa: report of two cases and literature review

Malignant tumors of the nasal and paranasal cavities account for only 3-5% of all head and neck neoplasms. Among these tumors, rare instances of human papillomavirus (HPV)-positive multiphenotypic carcinomas and biphenotypic sarcomas have been documented. Two such cases are reported here, along with the respective treatment approaches. The first involved a 39-year-old male patient diagnosed with HPV-positive multiphenotypic carcinoma. Surgical treatment was performed through a craniofacial and transfacial approach, en bloc resection, and reconstruction of the anterior cranial base with a fascia lata graft and pericranial flap. The second involved a 41-year-old female patient diagnosed with biphenotypic sarcoma. Surgical treatment was performed through centripetal endoscopic tumour resection. In both cases, adjuvant radiotherapy was performed after obtaining the histopathological result and negative margins. Both patients were free of disease during postoperative follow-up. Given the rarity of these cases, there are no established guidelines outlining specific treatments. It is recommended that such tumours are assessed in interdisciplinary committees to determine the optimal treatment options. Typically, this will involve surgical resection via craniofacial and transfacial approaches or endoscopic surgery, depending on the diagnosis, extent of anatomical involvement, and tumour aggressiveness. Additionally, the potential benefits of adjuvant radiotherapy should be evaluated, as it has demonstrated promising outcomes, even in cases with positive margins.

Whole exome sequencing of human papillomavirus-related multiphenotypic sinonasal carcinoma: a case report

Human Papillomavirus (HPV) related Multiphenotypic Sinonasal Carcinoma (HMSC) is a rare tumor with features of both atypical squamous cell and adenoid cystic carcinoma, making diagnosis challenging. Approximately 80% of HMSC cases carries HPV type 33 followed by type 35. We present a patient with HMSC. Pathological classification was aided by immunohistochemistry (IHC). The presence of HPV-DNA was tested using PCR and HPV E6/E7 expression by RNA in situ hybridization (RNA ISH). Whole exome sequencing (WES) was used to identify somatic gene mutations and copy number alterations. A 55-year-old male presented with an HMSC in the right nostril. Histological examination showed a solid basaloid subtype with mucinous spaces and ductal structures. IHC showed positive staining for SOX-10, SMA, p40, p63, PanCK, CK8 and MYB. Diffuse positive staining for p16 was observed and PCR and RNA ISH indicated the presence of HPV type 35. The patient was treated with endoscopic surgery and radiotherapy and is currently alive and recurrence-free after 16 months of follow-up. WES revealed 38 somatic sequence variants and several chromosomal regions with copy number alterations, including a copy number gain at 6q23 where MYB is located. EP300, ZNF22, ZNF609 and LRIG3 are some of the genes whose mutations were indicated as probably pathogenic. We did not find mutations predictive for drug response according to the ESMO Scale for Clinical Actionability of Molecular Targets database. This is the first report of WES analysis of an HMSC, in this case associated with HPV type 35. The detected mutation in EP300 and the overexpression of MYB may serve as molecular targets for personalized therapy.

HPV-Related Multiphenotypic Sinonasal Carcinoma: A Clinicoradiological Series of 3 Cases With Full Endoscopic Surgical Outcome

Context: Human papillomavirus (HPV)-related multiphenotypic sinonasal carcinoma (HMSC), formerly known as HPV-related carcinoma with adenoid cystic like features, is a rare tumor subtype with unusual correlation between radiological, histopathological, and surgical findings. The shared histological characteristics with other sinonasal tumors make the diagnosis challenging. Optimal surgical and oncological treatments for this rare condition remains to be clearly defined. Methods: The objective of the study was to describe the unique characteristics and endoscopic surgical treatment of this rare tumor. In this retrospective case series, all patients with an HMSC diagnosis treated in our tertiary center were selected. Results: Three HMSC cases were identified, including 2 male and 1 female patients. All cases originated from the posterior nasal cavity. One case presented with a tumor of 8.9 cm × 6.4 cm × 8.7 cm, which is the largest tumor volume described to date. All patients received exclusively endoscopic surgical treatment, followed by adjuvant radiation therapy. No patient showed clinical or radiological sign of disease recurrence, or regional or distant metastasis, with a follow-up ranging from 9 months to 4 years. In 2 cases, initial diagnoses incorrectly suggested adenoid cystic or basaloid squamous cell carcinoma. HPV-DNA testing confirmed the presence of HPV in all cases, with identification of strains 16 and 18. Conclusion and Relevance: HMSC represents a newly identified diagnosis that constitutes a significant challenge for both clinicians and pathologists. It is crucial to acknowledge its indolent clinical course and the apparent contradiction between aggressive radiological features and the noninvasive nature of surgical findings. Skull base surgeons should be aware that, despite these complexities, endoscopic treatment is achievable in the majority of cases. This understanding is essential for the effective management of HMSC.