Low-Grade Papillary Schneiderian Carcinoma: A Case Report

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.

Translocations and Gene Fusions in Sinonasal Malignancies

PURPOSE OF REVIEW

During the past few years there has been an expansion in our understanding of gene fusions and translocations involved in cancer of the sinonasal tract. Here we review the downstream biologic effects, clinical characteristics, and pathologic features of these tumors. The molecular consequences and neo-antigens resulting from these chromosomal aberrations are considered and targets for current and future clinical trials discussed.

RECENT FINDINGS

Several new, clinically relevant, chromosomal aberrations have been discovered and evaluated to varying degrees in sinonasal tumors including DEK::AFF2, BRD4::NUT, ADCK4::NUMBL, and ETV6::NTRK3. Sinonasal malignancies demonstrate a diverse genetic landscape and varying clinical courses. Recent studies illustrate that gene fusions and translocations may play a role in carcinogenesis in certain sinonasal tumor subtypes and may be used to develop new biomarker-driven and patient-centered treatments.

DEK::AFF2 Fusion Carcinomas of Head and Neck

A novel DEK::AFF2 fusion carcinoma was recently described in 29 patients who originally presented with non-viral-associated nonkeratinizing squamous cell carcinoma. The tumors occurred at multiple sites in the head and neck including in the sinonasal tract, middle ear, and temporal bone. This tumor behaves aggressively involving adjacent vital structures, frequently recurs, and is inclined to develop lymph node and distant metastasis. This review aims to summarize the demographic, clinical, pathologic, immunophenotypic features, and pattern of molecular alterations as well as to discuss the differential diagnosis of DEK::AFF2 fusion carcinoma.

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.

DEK-AFF2 Carcinoma of the Sinonasal Region and Skull Base: Detailed Clinicopathologic Characterization of a Distinctive Entity

A novel DEK-AFF2 fusion was recently reported in 4 nonkeratinizing squamous cell carcinomas of the sinonasal region and skull base, including 1 with exceptional response to immunotherapy, but it is not yet clear if this rearrangement defines a unique clinicopathologic category or represents a rare event. This study aims to characterize a larger cohort of carcinomas with DEK-AFF2 fusions to assess whether they truly constitute a distinctive entity. Among 27 sinonasal and skull base nonkeratinizing squamous cell carcinoma that were negative for human papillomavirus and Epstein-Barr virus, RNA sequencing identified DEK-AFF2 fusions in 13 cases (48%). Nine were centered in the nasal cavity, 2 in the middle ear/temporal bone, 1 in the nasopharynx, and 1 in the orbit. These tumors displayed recurrent histologic features including (1) complex endophytic and exophytic, frequently papilloma-like growth, (2) transitional epithelium with eosinophilic to amphophilic cytoplasm, (3) absent or minimal keratinization with occasional compact keratin pearls, (4) monotonous nuclei, and (5) prominent tumor-infiltrating neutrophils or stromal lymphocytes. This appearance not only overlaps with high-grade basaloid sinonasal carcinomas but also with benign papillomas and tumors reported as low-grade papillary Schneiderian carcinoma. However, DEK-AFF2 carcinomas showed frequent local recurrence, cervical lymph node metastases, and distant metastasis with 2 deaths from disease, confirming they are aggressive malignancies despite relatively bland histology. Overall, the distinctive molecular, histologic, and clinical features of DEK-AFF2 carcinomas suggest they represent a unique entity in the sinonasal region. This tumor merits increased pathologic recognition to better understand its prognostic and therapeutic implications.

DEK-AFF2 fusion-associated papillary squamous cell carcinoma of the sinonasal tract: clinicopathologic characterization of seven cases with deceptively bland morphology

A novel DEK-AFF2 fusion has been recently identified in four cases of basaloid to nonkeratinizing squamous cell carcinoma (SCC) in the sinonasal tract and middle ear with high-grade morphology. The exceptional response to immune checkpoint inhibitor in the first reported case highlights the potential clinical importance of identifying tumors with DEK-AFF2 fusions. We herein reported the first series of seven cases of DEK-AFF2 fusion-associated sinonasal SCC with deceptively bland morphology, including four cases of low-grade papillary Schneiderian carcinoma, which is a recently described tumor type with unknown molecular underpinnings. The DEK gene rearrangement was confirmed by DEK break-apart fluorescence in situ hybridization and DEK-AFF2 fusion transcripts were detected by reverse transcription polymerase chain reaction. In contrast to the previously reported DEK-AFF2 fusion-positive high-grade carcinomas, these tumors had a monotonous and bland morphology and were all initially diagnosed as sinonasal papilloma (SP) of various types, with or without dysplasia or carcinoma in situ. The tumor was characterized by mixed exophytic and inverted patterns, broad papillary fronds, acantholytic change, cellular monotony, dense neutrophilic infiltrates, and peripheral palisading. All tumors were diffusely positive for p40 or p63 and negative for NUT and p16. Molecular drivers associated with SP, including EGFR and KRAS mutations and both high and low-risk human papillomavirus infection, were negative in all cases. Although there was no overt stromal invasion or desmoplastic reaction in the initial specimens, these tumors tended to progress locoregionally through a prolonged clinical course and occasionally develop lymph node metastases, high-grade transformation, or extensively local destruction eventually leading to death. These justify more aggressive clinical management. Therefore, we propose the new terminology "DEK-AFF2 fusion-associated papillary SCC of the sinonasal tract" to better describe this clinicopathologically and molecularly distinct entity.

Low Grade Papillary Sinonasal (Schneiderian) Carcinoma: A Series of Five Cases of a Unique Malignant Neoplasm with Comparison to Inverted Papilloma and Conventional Nonkeratinizing Squamous Cell Carcinoma

There have been a few case reports and one small series of low grade papillary sinonasal (Schneiderian) carcinomas (LGPSC) which mimic papillomas but have overtly invasive growth and which occasionally metastasize. We describe the morphologic, clinical, immunohistochemical, and molecular features of five patients with LGPSC compared with eight cases each of inverted papilloma (IP) and conventional nonkeratinizing squamous cell carcinoma (SCC) with papillary growth. All LGPSC were nested with predominantly pushing invasion, no stromal reaction, and frequent surface papillary growth. All consisted of one cell type only, with polygonal cells with round nuclei, no (or limited) cytologic atypia, low mitotic activity, and prominent neutrophilic infiltrate. One patient had slightly more infiltrative bone invasion, another lymphovascular, perineural, and skeletal muscle invasion, and a third nodal metastasis after 17 years. By comparison, IPs had bland cytology, neutrophilic microabscesses, mixed immature squamous, goblet cell, and respiratory epithelium, and extremely low mitotic activity. Nonkeratinizing SCCs had basaloid-appearing cells with nuclear pleomorphism, brisk mitotic activity, and apoptosis. All LGPSC were p63 positive. Mitotic activity and Ki67 indices were significantly higher for LGPSCs than IPs and significantly lower than NKSCCs, while p53 immunohistochemistry in LGPSC was identical to nonkeratinizing SCC and higher than for IP. Sequencing showed all five tumors to harbor a MUC6 mutation, one tumor to harbor CDKN2A and PIK3R1 mutations, and one tumor to harbor a NOTCH1 mutation. All LGPSC lacked EGFR and KRAS mutations and lacked copy number variations of any main cancer genes. At a median follow up of 12 months, two LGPSC recurred locally, and one patient died after massive local recurrences and nodal metastases. LGPSC is a distinct, de novo sinonasal carcinoma that can be differentiated from papillomas by morphology and selected immunohistochemistry.

Clinicopathological analysis of low-grade papillary Schneiderian carcinoma: report of five new cases and review of the literature

AIMS

Low-grade papillary Schneiderian carcinoma (LGPSC) is a rare and newly described entity of the sinonasal tract. The aim of this study was to evaluate the clinicopathological and molecular characteristics in order to identify typical features for differential diagnosis.

METHODS AND RESULTS

Of the 3000 cases of sinonasal tumour studied during a period of 6 years, five cases were reviewed and diagnosed as LGPSC. All five patients were female (mean age, 47.8 years; range, 18-64 years) and had undergone multiple surgeries (3-10 surgeries). Both the sinonasal tract and the middle ear were involved in four patients. Nodal metastasis occurred in two patients, and one patient developed a distant metastasis to the left lung. Histologically, tumours had branched and crowded papillae with pushing boundaries. Tumour epithelia were multilayered and arranged in an orderly pattern without cilia. No malignant cytological features were observed in any of the cases. Immunohistochemical findings revealed a scattered distribution of Ki67-positive cells and positive staining for epithelial membrane antigen, mainly in the outermost-layer cells. Human papillomavirus (HPV) DNA was found in two patients and genotyped as HPV type 16. Sanger sequencing did not reveal any epidermal growth factor receptor or Kirsten rat sarcoma viral oncogene homologue gene mutation in the five cases.

CONCLUSIONS

We report on five new cases of LGPSC, and confirm LGPSC as a new sinonasal carcinoma that behaves aggressively with metastatic potential. The combination of clinical behaviour and typical histological features can distinguish LGPSC from sinonasal papilloma and other carcinomas.

Malignant Transformation of Schneiderian Papilloma Presenting With Progressive Binocular Diplopia and Blepharoptosis

Sinonasal tumors arising from Schneiderian papillomas, most frequently associated with squamous cell carcinoma (SCC), are rare and often present with non-specific symptoms, even in an advanced stage. Herein, we report the case of a 61-year-old male who presented with a four-month history of progressive binocular diplopia, blepharoptosis, and amblyopia, and upon the essential diagnostic work-up he was subsequently diagnosed with SCC arising from an SP. Surgical management was not warranted due to the extent of the disease, so induction chemotherapy with cisplatin and 5-fluorouracil (5-FU) was commenced, followed by definitive concurrent chemoradiotherapy (CRT). The patient was still alive at 25 months after his first presentation, receiving supportive care. Our case highlights the importance of early recognition of neuro-ophthalmological disorders related to sinonasal carcinomas, as diagnostic delay may lead to both functional complications and higher morbidity.

Low-Grade Papillary Schneiderian Carcinoma: Report of a Case with Molecular Characterization

In 2015, Lewis et al. first described low-grade papillary Scheneiderian carcinoma (LGPSC) of the sinonasal tract. Their case resembled a sinonasal papilloma clinically and histopathologically; however, invasion and metastasis resulted in the death of the patient despite absence of malignant cytologic features. Additional reports established LGPSC as a distinct entity and characterized its immunohistochemical profile. Diffuse expression of low molecular weight cytokeratins, positivity for p16 and p53 in at least 50% of cells, a high Ki-67 index, and absence of human papillomavirus (HPV)-DNA was observed across all reported cases. We report an additional case of LGPSC and describe the clinical, histologic, and immunohistochemical features. In contrast to sinonasal papillomas, the case was negative for HPV-DNA and showed no mutations in the EGFR and KRAS hotspot regions.

Low-Grade Papillary Schneiderian Carcinoma of the Sinonasal Cavity and Temporal Bone

OBJECTIVES:

The aim of this study was to further characterize a newly described neoplasm, low-grade papillary Schneiderian carcinoma, occurring simultaneously in the sinonasal cavity and mastoid. Additionally, the authors review the only 2 similar cases within the literature and describe the common clinical features, radiographic findings, and pathologic characteristics of this exceptionally rare disease process.

METHODS:

Chart review for single patient, review of literature.

RESULTS:

The patient presented with bilateral nasal obstruction. Computed tomography revealed a left sinonasal mass with skull base hyperostosis, and follow-up magnetic resonance imaging showed a concomitant olfactory groove meningioma. Examination showed a bilateral, completely obstructing sinonasal mass with skip areas, and biopsy confirmed inverted papilloma (human papilloma virus strains 16 and 18 indeterminate). The patient underwent bilateral endoscopic sinus surgery, left medial maxillectomy, and left partial nasopharyngectomy. Given her multifocal disease, she was advised that she would require additional excision, but was lost to follow up. One year later she developed acute left facial paralysis. Magnetic resonance imaging demonstrated an enhancing mass in the left mastoid with enhancement along the Eustachian tube in addition to her known recurrent sinonasal disease. Simultaneous endoscopic sinus surgery and mastoidectomy were performed. Polypoid tissue was removed from the nasopharynx, mesotympanum, epitympanum, and retrofacial air cells. Immunohistochemistry showed that cells stained positive for p63 and dermCK and negative for synaptophysin. Morphologically, cells were bland, without classic stromal invasion, retaining their smooth, cystic, and papillary features, despite their increased depth within the tissue. Upon further review and consultation with an outside pathologist, a diagnosis of low-grade papillary Schneiderian carcinoma was made. The patient was referred for radiation therapy and is disease free at 3-month follow-up, with return of her facial function.

CONCLUSIONS:

This case represents the first report of concurrent low-grade papillary Schneiderian carcinoma of both the nasal cavity and mastoid. It emphasizes the importance of recognizing this new entity through pathologic analysis and suspecting it when the clinical course does not follow an expected pattern.