Low-grade papillary Schneiderian carcinoma with TP53 mutation: a case report and review of the literature

BACKGROUND

Low-grade papillary Schneiderian carcinoma (LGPSC) is a relatively new entity of the sinonasal tract and is characterized by a bland morphology simulating sinonasal papilloma, invasive growth pattern with pushing borders, and aggressive clinical behavior with multiple recurrences and metastatic potential. Recently, DEK::AFF2 fusions were identified in LGPSC. However, some LPGSCs lack DEK::AFF2 fusion, and the molecular features of these tumors have not been clarified.

CASE PRESENTATION

A 69-year-old man presented with a discharge of pus from his left cheek. Computed tomography revealed a mass involving the left maxillary sinus, ethmoid sinus, and nasal cavity with the destruction of the orbital wall. The biopsy specimens showed that the tumor had a predominantly exophytic, papillary growth and did not have an apparent stromal invasion. The tumor was composed of multilayered epithelium that showed bland morphology with a round to polygonal shape, abundant eosinophilic cytoplasm, and uniform nuclei. Dense neutrophilic infiltrates were focally present. Immunohistochemically, CK5/6 was strongly and diffusely positive, and p16 was negative. p63 was mainly positive in the basal layer, and EMA was predominantly expressed in the outermost cell layer. DNA-based targeted sequencing showed TP53 R175H mutation, whereas neither EGFR nor KRAS mutation was identified. Reverse transcription polymerase chain reaction and fluorescence in situ hybridization revealed no DEK::AFF2 fusion.

CONCLUSIONS

We describe the first case of TP53-mutant LGPSC and review the literature. LGPSC is a genetically heterogeneous entity, and the recognition of this rare entity and comprehensive assessment of clinicopathological and molecular findings are crucial for the correct pathological diagnosis and clinical management.

Nasopharyngeal low-grade papillary schneiderian carcinoma with cervical metastasis

Low-grade papillary Schneiderian carcinoma (LGPSC) is a rare and newly described type of cancer arising from the Schneiderian epithelium. Owing to cellular atypia, it is difficult to differentiate this type from other papillomas and malignancies. Although this condition remains unclear, it is associated with mortality and recurrence. Therefore, treating physicians should be aware of the possibility of LGPSC for prompt diagnosis and treatment. In this article, we present an additional case of nasopharyngeal LGPSC with cervical lymph node metastasis and reviewed the 14 cases reported thus far in the literature. A 76-year-old female was referred to our department for detailed examination of nasopharyngeal and cervical lymph node tumors detected by positron emission tomography-computed tomography. Based on the biopsy of the nasopharyngeal tumor, we suspected LGPSC. Considering the clinical course and pathological findings, the patient was diagnosed with cervical lymph node metastasis through neck dissection. We performed radiotherapy for the primary lesion of the nasopharynx, which led to the disappearance of the tumor. After 13 months following the radiotherapy, the patient died from a recurrence of retroperitoneal liposarcoma without the recurrence of LGPSC.